Ground driving device with double anti-reverse protection permanent magnet motor

Abstract

The invention discloses a dual anti-reverse protection permanent magnet motor ground driving device, and relates to the technical field of oil field machinery, the dual anti-reverse protection permanent magnet motor ground driving device comprises a permanent magnet motor, a connecting seat and a braking system, the braking system comprises an electromagnetic braking module and a friction braking module, and the friction braking module comprises a fixing frame fixedly installed in the connecting seat; a mounting frame rotationally arranged on the output shaft in a sleeving mode is arranged in the fixing frame, a one-way transmission gear set is arranged between the mounting frame and the output shaft so that the one-way transmission gear set can only allow one-way transmission, and a variable pressure friction mechanism is arranged between the mounting frame and the fixing frame; the electromagnetic braking module comprises a switching circuit and a braking resistor, and the switching circuit switches the winding of the permanent magnet motor from the driving end to the braking resistor when the output shaft rotates reversely. The electromagnetic braking module and the friction braking module are adopted for preventing reverse rotation to adapt to different stages of reverse rotation braking, so that reverse rotation braking of the oil pumping pipe is more stable.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield machinery, and in particular to a ground drive device of a permanent magnet motor with double anti-reverse protection. Background Art

[0002] In a screw pump production system, when the motor suddenly loses power or shuts down, the sucker rod string undergoes high-speed reverse rotation due to the release of elastic deformation energy and the action of crude oil gravity. Specifically, the sucker rod is subjected to tensile and torsional stresses under normal operating conditions, storing a large amount of elastic potential energy. Once power is interrupted, this energy is rapidly released, driving the sucker rod to reverse rotation. Simultaneously, the crude oil in the wellbore flows back under the action of gravity, further accelerating the reverse rotation speed. The sucker rod connection thread is typically right-handed, and reverse rotation generates a loosening torque. At excessive speeds, the threaded connection can completely loosen, causing the rod string to fall to the bottom of the well and causing a serious well repair accident. Furthermore, high-speed reverse rotation can impact the drive motor and wellhead assembly, shortening the equipment life. Therefore, the installation of an anti-reverse device is essential.

[0003] There are three main types of common anti-reversal technologies, but all of them have significant defects: Ratchet-pawl mechanical braking relies on hard locking, generating huge impact torque at the moment of braking, far exceeding the API thread safety limit, which can easily cause thread damage or pawl cracking; hydraulic braking has a delayed response and cannot effectively suppress the initial high-torque stage, and requires an additional hydraulic pump station, and the braking force control needs to be equipped with an additional electronic control system, which increases costs; electromagnetic braking takes a long time, and when suppressing high-speed reversal, the permanent magnet motor and brake resistor continue to heat up, which can easily cause permanent magnet demagnetization and resistor damage. Summary of the invention

[0004] The purpose of the present invention is to solve the problem of reverse braking when the oil field pumping rod suddenly reverses, and to propose a double anti-reverse protection permanent magnet motor ground drive device.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A double anti-reverse protection permanent magnet motor ground drive device includes a permanent magnet motor, a connecting seat and a braking system, wherein: The output shaft of the permanent magnet motor passes through the connecting seat and is fixedly connected to the sucker rod; The braking system includes an electromagnetic braking module and a friction braking module, wherein: The friction braking module includes a fixed frame fixedly installed in the connecting seat. Inside the fixed frame, there is a mounting bracket rotatably sleeved on the output shaft. A one-way transmission gear set is arranged between the mounting bracket and the output shaft to allow only one-way transmission. A variable-pressure friction mechanism is arranged between the mounting bracket and the fixed frame to configure the magnitude of the friction braking force according to the reverse rotation speed of the output shaft; The electromagnetic braking module includes a switching circuit and a braking resistor. When the output shaft rotates reversely, the switching circuit switches the winding of the permanent magnet motor from the driving end to the braking resistor to form a power generation energy consumption loop.

[0006] Preferably, the permanent magnet motor is fixedly connected to the oil production well pipe through a connecting seat. The side of the connecting seat has an opening, and the opening is shielded by a grille.

[0007] Preferably, the mounting bracket includes: Two piece rings, and the two piece rings are rotatably sleeved on the output shaft; A plurality of extension plates, which are evenly distributed on the side wall of the piece ring, and the extension plates of the two piece rings are opposite in position; A connecting shaft, fixedly installed between the corresponding two extension plates and parallel to the output shaft.

[0008] Preferably, the one-way transmission gear set includes a braking gear fixedly arranged on the output shaft, and the braking gear is located between the two piece rings; A connecting gear meshing with the braking gear is sleeved on the connecting shaft, and a one-way bearing is arranged between the connecting gear and the connecting shaft.

[0009] Preferably, the inner ring of the one-way bearing is fixed to the outer wall of the connecting shaft, and the outer ring is fixed to the inner wall of the connecting gear, and is configured as: When the output shaft rotates forward and the braking gear drives the connecting gear, the connecting gear and the connecting shaft rotate freely; When the output shaft rotates reversely and the braking gear drives the connecting gear, the connecting gear and the connecting shaft are locked.

[0010] Preferably, the variable-pressure friction mechanism includes two annular friction rings, and the two annular friction rings are fixedly installed on the inner top surface and the inner bottom surface of the fixed frame; Installation rings are slidably inserted at both ends of the connecting shaft, and friction plates are installed at one end of the installation ring close to the annular friction ring; A pressurizing ring is rotatably connected to the connecting shaft, and the pressurizing ring is located between the extension plate and the installation ring. The same connecting arm is fixedly installed between the pressurizing rings at both ends of the connecting shaft, and a counterweight is installed at the distal end of the connecting arm. A rotary pushing structure is arranged between the pressurizing ring and the installation ring. When the connecting arm deflects due to the centrifugal force of the counterweight, it drives the installation ring to generate an axial displacement; A positioning spring is arranged between the connecting arm and the mounting bracket, so that the connecting arm is in a retracted state under non-external force, and at this time, the friction plate is in contact with the surface of the annular friction ring.

[0011] Preferably, the rotation and pushing structure includes a spiral inclined surface arranged on the side of the pressure increasing ring close to the mounting ring, a matching inclined surface adapted to the spiral inclined surface is arranged on the end surface of the mounting ring, and an axial drop of 0-2 mm can be generated between the spiral inclined surface and the matching inclined surface.

[0012] Preferably, a radially penetrating limiting port is formed in the connecting shaft, and a limiting rod slidably adapted to the limiting port is arranged in the mounting ring.

[0013] Preferably, the friction plate is arc-shaped and is concentrically arranged with the annular friction ring, and the rotation path of the friction plate around the output shaft coincides with that of the annular friction ring.

[0014] Preferably, the switching circuit includes: A first contactor for connecting the permanent magnet motor and the driving power supply; A second contactor for connecting the permanent magnet motor and the braking resistor.

[0015] The present invention has the following advantages compared with the prior art: The present invention adopts a dual anti-reverse mechanism of an electromagnetic braking module and a friction braking module. When the oil pumping pipe reverses, the electromagnetic braking module forms a power generation energy consumption loop through the permanent magnet motor winding and the braking resistor, and uses the electromagnetic damping effect to quickly absorb the reverse kinetic energy and provide an initial braking torque. This process has no mechanical contact, avoids the impact wear of traditional brakes, and at the same time reduces the impact torque in the initial stage of reverse, effectively preventing the loosening of the threaded connection of the sucker rod.

[0016] Due to the limited electromagnetic braking effect, during the process of counteracting the reverse, the rotation speed of the oil pumping pipe will gradually increase and then decrease. When the rotation speed increases, the present invention drives the axial displacement of the pressure increasing ring through the centrifugal force of the counterweight block by the friction braking module, so that the contact pressure between the friction plate and the annular friction ring increases with the increase of the rotation speed. At this time, the reverse torque has decreased. The friction braking module shares the load of the electromagnetic braking module to accelerate the braking process, avoids the over-temperature rise of the braking resistor due to continuous large current, prolongs the service life of the braking resistor, and adapts to different stages of the reverse braking of the oil pumping pipe through the dual anti-reverse mechanism, so that the reverse braking of the oil pumping pipe is more stable.

[0017] The present invention gradually reduces the contact pressure between the friction plate and the annular friction ring through the variable-pressure friction mechanism during the speed reduction stage, and the braking force linearly decays, ensuring that the residual kinetic energy is consumed flexibly, avoiding the stop impact, and avoiding the threaded connection from bearing the impact torque. Description of the Drawings

[0018] Figure 1 Schematic diagram of the overall structure of a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 2 Cross - sectional structure schematic diagram of a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 3 Partial structure schematic diagram of a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 4 Circuit connection schematic diagram of the electromagnetic braking module in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 5 Structure schematic diagram of the friction braking module in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 6 Cross - sectional structure schematic diagram of the friction braking module in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 7 Structure schematic diagram of the variable - pressure friction mechanism in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 8 Structure schematic diagram of the mounting bracket in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 9 Structure schematic diagram of the fixed frame in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 10 Structure schematic diagram of the connecting arm in the centrifugal outward - displacement state in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention; Figure 11 Exploded structure schematic diagram of the connecting shaft in a two - fold anti - reverse protection permanent magnet motor surface drive device proposed by the present invention.

[0019] In the figure: 1, permanent magnet motor; 11, output shaft; 2, connecting seat; 3, oil production well pipe; 31, sucker rod; 4, electromagnetic braking module; 41, switching circuit; 411, first contactor; 412, second contactor; 42, braking resistor; 5, friction braking module; 51, fixed frame; 52, mounting bracket; 521, shim ring; 522, extension plate; 523, connecting shaft; 5231, limiting port; 53, variable - pressure friction mechanism; 531, annular friction ring; 532, mounting ring; 5321, limiting rod; 533, friction plate; 534, pressure - increasing ring; 535, connecting arm; 536, counterweight; 537, positioning spring; 538, spiral inclined plane; 539, mating inclined plane; 54, braking gear; 55, connecting gear; 56, one - way bearing. Detailed implementation manners

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention.

[0021] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0022] Refer to Figures 1-4 , a two - fold anti - reverse protection permanent - magnet motor surface drive device, comprising a permanent - magnet motor 1, a connecting seat 2 and a braking system.

[0023] The output shaft 11 of the permanent - magnet motor 1 passes through the connecting seat 2 and is fixedly and drivingly connected to the sucker rod 31. In the prior art, the connection between the motor and the sucker rod is usually indirectly transmitted through a belt or a gear, which has problems such as low transmission efficiency. In this device, the permanent - magnet motor 1 is fixedly connected to the pumping well pipe 3 through the connecting seat 2. This connection method ensures the overall stability of the motor and the pumping system, and the output shaft 11 directly drives the sucker rod 31 to improve the transmission efficiency.

[0024] Refer to Figures 1-3 , the permanent - magnet motor 1 is fixedly connected to the pumping well pipe 3 through the connecting seat 2. The side of the connecting seat 2 has an opening, and the opening is shielded by a grille. The opening facilitates the inspection and maintenance of the inside of the connecting seat 2. At the same time, due to the air flow, it can improve the heat dissipation effect of the braking system, and the grille shielding can effectively prevent foreign objects from entering the inside of the connecting seat 2 and avoid damage to the internal transmission components.

[0025] Refer to Figures 1-6The braking system includes an electromagnetic brake module 4 and a friction brake module 5, which are used to brake the sucker rod 31 when it suddenly stops due to the release of elastic deformation energy and the reversal caused by the gravity of crude oil. The braking of the sucker rod 31 is divided into multiple stages. In the initial torsional stage, the elastic deformation energy is quickly released, forming a torque peak, and the speed is relatively low. As the torque decays, the gravity potential energy of the crude oil is converted to drive the sucker rod 31 to accelerate the speed, and enter the acceleration stage. When the speed peak is reached, the fluid resistance and residual energy cause the sucker rod 31 to enter the speed decay stage, and the torque is stable. The traditional single braking method is difficult to cope with the different stages of the braking process of the sucker rod 31. For example, the ratchet-pawl mechanical brake is rigidly locked in the initial torsional stage, and a huge impact torque is generated at the moment of braking, which far exceeds the API thread safety limit and can easily cause thread damage or pawl cracking. When the electromagnetic brake suppresses high-speed reversal, the motor and resistor continue to heat up, which can easily cause permanent magnet demagnetization and resistor damage.

[0026] This braking system adopts a dual anti-reversal mechanism of electromagnetic brake module 4 and friction brake module 5. In the initial torsion stage, the electromagnetic brake module 4 uses the electromagnetic damping effect to quickly absorb the reverse kinetic energy and provide the initial braking torque. This process has no mechanical contact, which reduces the impact torque at the initial stage of reversal and effectively prevents the threaded connection of the sucker rod 31 from loosening. In the acceleration stage, braking is carried out through the friction brake module 5, and the braking force increases with the increase of speed, sharing the load of the electromagnetic brake module 4, accelerating the braking process, avoiding the electromagnetic brake module 4 from exceeding the temperature limit due to continuous large current, and extending the service life of the brake resistor 42. In the deceleration stage, the braking force of the friction brake module 5 is gradually reduced, and the braking force decays linearly to ensure the flexible consumption of residual kinetic energy, avoid the stall impact caused by excessive braking speed, and reduce the risk of damage to the thread by impact torque.

[0027] The electromagnetic brake module 4 includes a switching circuit 41 and a braking resistor 42. When the output shaft 11 reverses, the switching circuit 41 switches the winding of the permanent magnet motor 1 from the driving end to the braking resistor 42, forming a power generation and energy consumption loop. When the output shaft 11 reverses, the switching circuit 41 acts quickly to switch the winding of the permanent magnet motor 1 to the braking resistor 42. At this time, the motor is equivalent to a generator, converting the reverse mechanical energy into electrical energy and consuming it through the braking resistor 42, thereby achieving rapid braking, which can effectively suppress the reversal of the sucker rod 31 in a short time, and the braking process is smooth, reducing the impact on the permanent magnet motor 1 and the transmission system.

[0028] Reference Figures 1-4, the switching circuit 41 includes a first contactor 411 and a second contactor 412. The first contactor 411 is used to connect the permanent magnet motor 1 to the drive power supply. A frequency converter is also provided between the first contactor 411 and the drive power supply. The second contactor 412 is used to connect the permanent magnet motor 1 to the braking resistor 42. In the normal working state, the first contactor 411 is closed and the second contactor 412 is opened. The permanent magnet motor 1 is connected to the drive power supply to provide power for the sucker rod 31. When it is detected that the output shaft 11 rotates in reverse, the control system quickly controls the first contactor 411 to open and the second contactor 412 to close, realizing the switching of the windings, ensuring the timeliness and accuracy of the braking process. The reverse rotation of the output shaft 11 detects the reverse signal through sensors (such as encoders, Hall sensors), and then controls the opening and closing states of the first contactor 411 and the second contactor 412 through a PLC or a relay. The sensors and the controller are conventional existing technologies and will not be elaborated here, and it is easy to realize automatic control.

[0029] Refer to Figures 5-11 , the friction braking module 5 includes a fixed frame 51 fixedly installed in the connecting seat 2. The fixed frame 51 and the connecting seat 2 are fixed by bolts. The fixed frame 51 is sleeved outside the output shaft 11. An installation frame 52 rotatably sleeved on the output shaft 11 is arranged inside the fixed frame 51. A one-way transmission gear set is arranged between the installation frame 52 and the output shaft 11 to allow only one-way transmission. Under the action of the one-way transmission gear set, when the output shaft 11 rotates normally, the kinetic energy transmitted by the rotation of the output shaft 11 is consumed by the one-way transmission gear set, and the installation frame 52 does not rotate, so it does not affect the normal operation of the output shaft 11. When the output shaft 11 rotates in reverse, the one-way transmission gear set is in a locked state, and the rotation of the output shaft 11 is directly transmitted to the installation frame 52, driving the installation frame 52 to rotate. A variable-pressure friction mechanism 53 is arranged between the installation frame 52 and the fixed frame 51 to configure the magnitude of the friction braking force according to the reverse rotation speed of the output shaft 11. Under the action of the variable-pressure friction mechanism 53, there is a frictional resistance between the installation frame 52 and the fixed frame 51. This resistance ensures that the installation frame 52 can remain stationary when the output shaft 11 rotates normally. And when the output shaft 11 rotates in reverse, the installation frame 52 rotates with the output shaft 11, so that the frictional resistance between the installation frame 52 and the fixed frame 51 acts on the output shaft 11 to brake the output shaft 11.

[0030] Since the variable-pressure friction mechanism 53 can control the friction braking force according to the reverse rotation speed of the output shaft 11, it can provide different braking forces at different stages of the reverse rotation of the sucker rod 31, provide a large braking force at the high-speed stage to share the load of the electromagnetic braking module 4, and reduce the braking force at the low-speed stage to achieve a flexible stop.

[0031] Refer to Figures 5-11, the mounting bracket 52 includes two sheet rings 521, a plurality of extension plates 522 and a connecting shaft 523. The two sheet rings 521 are rotatably sleeved on the output shaft 11; the plurality of extension plates 522 are equidistantly distributed on the side wall of the sheet ring 521, and the extension plates 522 of the two sheet rings 521 are opposite in position; the connecting shaft 523 is fixedly installed between the corresponding two extension plates 522, and the connecting shaft 523 is parallel to the output shaft 11. The two sheet rings 521, the plurality of extension plates 522 and the connecting shaft 523 together form a frame structure, and the one-way transmission gear set is installed in this frame structure.

[0032] Referring to Figures 5-11 , the one-way transmission gear set includes a braking gear 54 fixedly arranged on the output shaft 11. The braking gear 54 is located between the two sheet rings 521; a connecting gear 55 meshing with the braking gear 54 is sleeved on the connecting shaft 523, and a one-way bearing 56 is arranged between the connecting gear 55 and the connecting shaft 523. The braking gear 54 rotates with the output shaft 11, and the braking gear 54 can drive the connecting gear 55. It should be noted that under the action of the one-way bearing 56, the braking gear 54 can only drive the connecting gear 55 to rotate in one direction. When the braking gear 54 drives the connecting gear 55 in the flexible direction, the connecting gear 55 rotates normally without affecting the operation of the output shaft 11. When the braking gear 54 drives the connecting gear 55 in the locking direction, the connecting gear 55 is in a locked state and cannot rotate. At this time, the power of the braking gear 54 directly acts on the mounting bracket 52 to drive the mounting bracket 52 to rotate, and the frictional resistance generated between the mounting bracket 52 and the fixed frame 51 under the action of the variable-pressure friction mechanism 53 will act on the braking gear 54 to brake the output shaft 11.

[0033] The inner ring of the one-way bearing 56 is fixed to the outer wall of the connecting shaft 523, and the outer ring is fixed to the inner wall of the connecting gear 55.

[0034] The one-way bearing 56 is configured as: When the output shaft 11 rotates forward and the braking gear 54 drives the connecting gear 55, the connecting gear 55 and the connecting shaft 523 rotate freely.

[0035] When the output shaft 11 rotates in the reverse direction and the braking gear 54 drives the connecting gear 55, the connecting gear 55 and the connecting shaft 523 are locked.

[0036] Referring to the figure, the variable-pressure friction mechanism 53 includes two annular friction rings 531. The two annular friction rings 531 are fixedly installed on the inner top surface and the inner bottom surface of the fixed frame 51, and the friction surfaces of the two annular friction rings 531 face each other.

[0037] Referring to Figures 5-11, mounting rings 532 are slidably inserted at both ends of the connecting shaft 523. A friction plate 533 is installed at one end of the mounting ring 532 close to the annular friction ring 531. The friction surface of the friction plate 533 faces the corresponding annular friction ring 531. Frictional force is generated by the contact between the friction plate 533 and the annular friction ring 531, serving as the braking force of the friction braking module 5. According to Coulomb's law of friction, the sliding frictional force between objects depends on the coefficient of friction of the material contact surface and the normal pressure between the two objects. Therefore, by controlling the normal pressure between the friction plate 533 and the annular friction ring 531, the frictional force can be correspondingly changed, so that the friction braking module 5 can adapt to different braking requirements.

[0038] Refer to Figures 5-11 , a pressure increasing ring 534 is rotatably connected to the connecting shaft 523. The pressure increasing ring 534 is located between the extension plate 522 and the mounting ring 532. The same connecting arm 535 is fixedly installed between the pressure increasing rings 534 at both ends of the same connecting shaft 523. A counterweight 536 is installed at the distal end of the connecting arm 535. When the output shaft 11 rotates in the reverse direction, the mounting bracket 52 is driven to rotate, and the connecting arm 535 will also rotate with the mounting bracket 52. Under the action of the centrifugal force of the counterweight 536, the connecting arm 535 deflects outward. A rotary pushing structure is provided between the pressure increasing ring 534 and the mounting ring 532. When the connecting arm 535 deflects under the centrifugal force of the counterweight 536, the mounting ring 532 is driven to generate an axial displacement. The axial displacement of the mounting ring 532 will drive the friction plate 533 to squeeze the annular friction ring 531, so that the normal pressure between the friction plate 533 and the annular friction ring 531 is increased, thereby increasing the frictional resistance.

[0039] A positioning spring 537 is provided between the connecting arm 535 and the mounting bracket 52, so that the connecting arm 535 is in a retracted state under non-external force. Since the connecting arm 535 deflects outward under centrifugal action and also deflects backward under inertial action, in order to ensure that the connecting arm 535 maintains an outward deflection trend during rotation, the deflection and retraction direction of the connecting arm 535 is the direction in which the connecting arm 535 rotates with the mounting bracket 52. When the connecting arm 535 is in the retracted state, the friction plate 533 is in contact with the surface of the annular friction ring 531. This state is the state of the minimum frictional force between the friction plate 533 and the annular friction ring 531. As the reverse rotation speed of the output shaft 11 increases, the centrifugal action becomes greater, which will cause the normal pressure between the friction plate 533 and the annular friction ring 531 to be greater, and vice versa. Therefore, when the reverse rotation speed of the output shaft 11 increases, the contact pressure between the friction plate 533 and the annular friction ring 531 increases with the increase in speed, realizing the sharing of the load of the electromagnetic braking module 4 and accelerating the braking process. After the speed is reduced, the contact pressure between the friction plate 533 and the annular friction ring 531 is gradually reduced, and the braking force decays linearly, ensuring that the residual kinetic energy is consumed flexibly and avoiding the stop impact.

[0040] Refer to Figures 5-11, the rotation and translation structure includes a spiral inclined surface 538 provided on the side of the pressure increasing ring 534 close to the mounting ring 532. A mating inclined surface 539 adapted to the spiral inclined surface 538 is provided on the end face of the mounting ring 532. When the connecting arm 535 deflects centrifugally, it will drive the pressure increasing ring 534 to rotate, causing the spiral inclined surface 538 and the mating inclined surface 539 to rotate relative to each other. The distance between the mounting ring 532 and the pressure increasing ring 534 increases, and the mounting ring 532 is pushed outwards. Due to the long moment arm of the connecting arm 535, according to the lever principle, sufficient driving force can be provided to the pressure increasing ring 534, and the friction plates 533 at both ends of the connecting shaft 523 move outwards synchronously, improving the friction braking effect. It should be noted that in practical applications, although the fixed frame 51, the mounting bracket 52, and the friction plates 533 are rigid structures, there will still be slight deformations under external forces. The spiral inclined surface 538 and the mating inclined surface 539 can generate an axial drop of 0 - 2 mm, and the axial drop compensates for the deformations of each component when the mounting ring 532 drives the friction plates 533 to axially extrude.

[0041] To improve the stability of the frictional force provided between the friction plates 533 and the annular friction ring 531, the number of connecting shafts 523 distributed around the mounting bracket 52 is at least two and needs to be equally spaced. In the embodiment, the number of connecting shafts 523 is four.

[0042] Refer to Figures 5-11 , a radially penetrating limiting port 5231 is provided on the connecting shaft 523, and a limiting rod 5321 slidably adapted to the limiting port 5231 is provided inside the mounting ring 532. Through the cooperation of the limiting port 5231 and the limiting rod 5321, the mounting ring 532 is limited, ensuring that only axial sliding can occur between the mounting ring 532 and the connecting shaft 523, and no circumferential rotation will occur, thereby ensuring the stability when the spiral inclined surface 538 and the mating inclined surface 539 are in contact and pressing.

[0043] The friction plates 533 are arc-shaped and are concentrically arranged with the annular friction ring 531. The rotation path of the friction plates 533 around the output shaft 11 coincides with that of the annular friction ring 531, ensuring the contact area between the friction plates 533 and the annular friction ring 531 to improve the friction braking effect.

[0044] The specific working principle of the present invention is as follows: During the normal driving stage, the permanent magnet motor 1 directly drives the sucker rod 31 through the output shaft 11, and the electromagnetic braking module 4 and the friction braking module 5 are in a non-working state.

[0045] In the switching circuit 41, the first contactor 411 is closed and the second contactor 412 is opened, and the motor winding is connected to the driving power supply.

[0046] In the friction braking module 5, the one-way transmission gear set is in a free rotation state, the mounting bracket 52 is stationary, and the friction plate 533 is in minimal pressure contact with the annular friction ring 531.

[0047] When the sucker rod 31 reverses due to the release of elastic deformation energy or the action of crude oil gravity, the electromagnetic braking module 4 and the friction braking module 5 work together in stages to achieve double anti-reverse protection.

[0048] When reverse rotation is triggered, the electromagnetic braking module 4 immediately disconnects the first contactor 411 and closes the second contactor 412, switching the permanent magnet motor 1 winding to the braking resistor 42 to form a power generation energy consumption loop. The permanent magnet motor 1 acts as a generator to convert the reverse mechanical energy into electrical energy, which is dissipated in the form of heat through the braking resistor 42 to quickly suppress the torque peak in the initial stage of reverse rotation.

[0049] When the output shaft 11 reverses, the one-way transmission gear set locks, and the braking gear 54 drives the connecting gear 55 and the entire mounting bracket 52 to rotate around its own axis. The counterweight 536 deflects outward due to centrifugal force, and through the action of the spiral inclined surfaces 538 and 539 of the connecting arm 535 and the pressure increasing ring 534, the mounting ring 532 is pushed axially to increase the positive pressure between the friction plate 533 and the annular friction ring 531.

[0050] The friction braking force increases linearly with the increase in speed, sharing the load of the electromagnetic braking module 4 to prevent its temperature from exceeding the limit due to continuous large current. When the reverse rotation speed reaches the peak value, the centrifugal force of the counterweight 536 is the largest, and the positive pressure between the friction plate 533 and the annular friction ring 531 reaches the maximum value, providing the maximum braking torque. The electromagnetic braking module 4 and the friction braking module 5 work together to quickly reduce the speed and shorten the braking time. When the reverse rotation speed decreases, the centrifugal force of the counterweight 536 decreases, the positive pressure between the friction plate 533 and the annular friction ring 531 decays linearly, and the braking force gradually decreases, ensuring that the residual kinetic energy is consumed in a flexible manner to avoid damage to the thread connection caused by the stop impact.

[0051] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A two - layer anti - reverse protection permanent magnet motor surface drive device, comprising a permanent magnet motor (1), a connecting seat (2) and a braking system, characterized in that: The output shaft (11) of the permanent magnet motor (1) penetrates through the connecting seat (2) and is fixedly and drivingly connected to the sucker rod (31); The braking system includes an electromagnetic braking module (4) and a friction braking module (5), wherein: The friction braking module (5) includes a fixed frame (51) fixedly installed in the connecting seat (2). Inside the fixed frame (51), there is a mounting frame (52) rotatably sleeved on the output shaft (11). A one - way transmission gear set is arranged between the mounting frame (52) and the output shaft (11) to allow only one - way transmission. A variable - pressure friction mechanism (53) is arranged between the mounting frame (52) and the fixed frame (51) to configure the magnitude of the friction braking force according to the reverse rotation speed of the output shaft (11); The electromagnetic braking module (4) includes a switching circuit (41) and a braking resistor (42). When the output shaft (11) rotates in reverse, the switching circuit (41) switches the winding of the permanent magnet motor (1) from the driving end to the braking resistor (42) to form a power - generating energy - consumption circuit.

2. A two-fold anti-reversal protection permanent magnet motor surface drive device according to claim 1, characterized in that, The permanent magnet motor (1) is fixedly connected to the oil production well pipe (3) through the connecting seat (2). The side of the connecting seat (2) has an opening, and the opening is shielded by a grille.

3. A two-fold anti-reversal protection permanent magnet motor surface drive device according to claim 1, characterized in that, The mounting frame (52) includes: Two piece - rings (521), and the two piece - rings (521) are rotatably sleeved on the output shaft (11); A number of extension plates (522), which are equidistantly distributed on the side wall of the piece - ring (521). The extension plates (522) of the two piece - rings (521) are in opposite positions; A connecting shaft (523), fixedly installed between the corresponding two extension plates (522) and parallel to the output shaft (11).

4. A two-fold anti-reversal protection permanent magnet motor surface drive device according to claim 3, characterized in that The one - way transmission gear set includes a braking gear (54) fixedly arranged on the output shaft (11), and the braking gear (54) is located between the two piece - rings (521); A connecting gear (55) meshing with the braking gear (54) is sleeved on the connecting shaft (523), and a one - way bearing (56) is arranged between the connecting gear (55) and the connecting shaft (523).

5. A two-fold anti-reversal protection permanent magnet motor surface drive device according to claim 4, characterized in that, The inner ring of the one - way bearing (56) is fixedly connected to the outer wall of the connecting shaft (523), and the outer ring is fixedly connected to the inner wall of the connecting gear (55), configured as: When the output shaft (11) rotates forward and the braking gear (54) drives the connecting gear (55), the connecting gear (55) and the connecting shaft (523) rotate freely; When the output shaft (11) rotates in reverse and the braking gear (54) drives the connecting gear (55), the connecting gear (55) and the connecting shaft (523) are locked.

6. The two - fold anti - reverse protection permanent magnet motor surface drive device according to claim 3, wherein, The variable - pressure friction mechanism (53) includes two annular friction rings (531), and the two annular friction rings (531) are fixedly installed on the inner top surface and the inner bottom surface of the fixed frame (51); Both ends of the connecting shaft (523) are slidably inserted with mounting rings (532), and a friction plate (533) is mounted at one end of the mounting ring (532) close to the annular friction ring (531); A pressure increasing ring (534) is rotatably connected to the connecting shaft (523). The pressure increasing ring (534) is located between the extension plate (522) and the mounting ring (532). The same connecting arm (535) is fixedly installed between the pressure increasing rings (534) at both ends of the connecting shaft (523). A counterweight (536) is installed at the distal end of the connecting arm (535). A rotary pushing structure is provided between the pressure increasing ring (534) and the mounting ring (532). When the connecting arm (535) deflects due to the centrifugal force of the counterweight (536), it drives the mounting ring (532) to generate an axial displacement; A positioning spring (537) is provided between the connecting arm (535) and the mounting frame (52), so that the connecting arm (535) is in a retracted state under non-external force. At this time, the friction plate (533) is in contact with the surface of the annular friction ring (531).

7. A two-fold anti-reversal protection permanent magnet motor surface drive device according to claim 6, characterized in that, The rotary pushing structure includes a spiral inclined surface (538) provided on the side of the pressure increasing ring (534) close to the mounting ring (532). A mating inclined surface (539) adapted to the spiral inclined surface (538) is provided on the end face of the mounting ring (532). The spiral inclined surface (538) and the mating inclined surface (539) can produce an axial drop of 0-2 mm.

8. A two - fold anti - reverse protection permanent magnet motor ground drive device according to claim 6, characterized in that, The connecting shaft (523) is provided with a radially penetrating limiting port (5231), and a limiting rod (5321) slidably adapted to the limiting port (5231) is arranged in the mounting ring (532).

9. A two-fold anti-reversal protection permanent magnet motor surface drive device according to claim 1, characterized in that, The friction plate (533) is arc-shaped and is concentric with the annular friction ring (531). The rotation path of the friction plate (533) around the output shaft (11) coincides with that of the annular friction ring (531).

10. A two-fold anti-reversal protection permanent magnet motor ground drive device according to claim 1, characterized in that, The switching circuit (41) includes: A first contactor (411) for connecting the permanent magnet motor (1) to the drive power supply; A second contactor (412) for connecting the permanent magnet motor (1) to the braking resistor (42).

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