A permanent magnet motor ground drive device with double anti-reverse protection

Abstract

The present invention discloses a permanent magnet motor ground drive device with double anti-reverse protection, which relates to the field of oilfield machinery technology. The device comprises a permanent magnet motor, a connecting seat, and a braking system. The braking system comprises an electromagnetic brake module and a friction brake module. The friction brake module comprises a fixed frame fixedly mounted in the connecting seat, a mounting bracket rotatably sleeved on the output shaft is provided inside the fixed frame, a one-way transmission gear set is provided between the mounting bracket and the output shaft to allow only one-way transmission, and a variable pressure friction mechanism is provided between the mounting bracket and the fixed frame. The electromagnetic brake module comprises a switching circuit and a braking resistor. The switching circuit switches the winding of the permanent magnet motor from the driving end to the braking resistor when the output shaft reverses. The present invention adopts a dual anti-reverse mechanism of the electromagnetic brake module and the friction brake module to adapt to different stages of reverse braking, thereby making the reverse braking of the oil pumping pipe 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:

[0004] 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

[0005] 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.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A double anti-reverse protection permanent magnet motor ground drive device includes a permanent magnet motor, a connecting seat and a braking system, wherein:

[0008] The output shaft of the permanent magnet motor passes through the connecting seat and is fixedly connected to the sucker rod;

[0009] The braking system includes an electromagnetic braking module and a friction braking module, wherein:

[0010] The friction brake module includes a fixed frame fixedly mounted in the connecting seat, a mounting bracket rotatably mounted on the output shaft is provided inside the fixing frame, a one-way transmission gear set is provided between the mounting bracket and the output shaft to allow only one-way transmission, and a variable pressure friction mechanism is provided between the mounting bracket and the fixing frame to adjust the magnitude of the friction braking force according to the reverse speed of the output shaft;

[0011] The electromagnetic brake module includes a switching circuit and a brake resistor. When the output shaft is reversed, the switching circuit switches the winding of the permanent magnet motor from the driving end to the brake resistor to form a power generation and energy consumption loop.

[0012] Preferably, the permanent magnet motor is fixedly connected to the oil well pipe via a connecting seat, and the side of the connecting seat has an open opening, which is shielded by a grille.

[0013] Preferably, the mounting frame comprises:

[0014] Two sheet rings, the two sheet rings are rotatably sleeved on the output shaft;

[0015] A plurality of extension plates are equidistantly distributed on the side wall of the sheet ring, and the extension plates of two sheet rings are opposite to each other;

[0016] The connecting shaft is fixedly installed between the corresponding two extension plates and is parallel to the output shaft.

[0017] Preferably, the one-way transmission gear set includes a brake gear fixedly arranged on the output shaft, and the brake gear is located between the two rings;

[0018] The connecting shaft is sleeved with a connecting gear meshing with the brake gear, and a one-way bearing is provided between the connecting gear and the connecting shaft.

[0019] 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 the configuration is as follows:

[0020] When the output shaft rotates in the forward direction and the brake gear drives the connecting gear, the connecting gear and the connecting shaft rotate freely;

[0021] When the output shaft rotates in the opposite direction and the brake gear drives the connecting gear, the connecting gear and the connecting shaft are locked.

[0022] Preferably, the variable pressure friction mechanism comprises two annular friction rings, which are fixedly mounted on the inner top surface and inner bottom surface of the fixed frame;

[0023] Mounting rings are slidably inserted at both ends of the connecting shaft, and a friction plate is installed at one end of the mounting ring close to the annular friction ring;

[0024] A boost ring is rotatably connected to the connecting shaft, and the boost ring is located between the extension plate and the mounting ring. A connecting arm is fixedly installed between the boost rings at both ends of the connecting shaft, and a counterweight is installed at the distal end of the connecting arm. A rotating push structure is provided between the boost ring and the mounting ring, and when the connecting arm is deflected by the centrifugal force of the counterweight, the mounting ring is driven to generate axial displacement;

[0025] A positioning spring is provided between the connecting arm and the mounting bracket, so that the connecting arm is in a retracted state when no external force is applied, and at this time, the friction plate is in contact with the surface of the annular friction ring.

[0026] Preferably, the rotary push structure includes a spiral bevel provided on the side of the boost ring close to the mounting ring, and the end face of the mounting ring is provided with a matching bevel adapted to the spiral bevel, and the spiral bevel and the matching bevel can produce an axial drop of 0-2mm.

[0027] Preferably, the connecting shaft is provided with a radially penetrating limiting opening, and a limiting rod is provided in the mounting ring and is slidably fitted with the limiting opening.

[0028] Preferably, the friction plate is arc-shaped and is arranged concentrically 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.

[0029] Preferably, the switching circuit includes:

[0030] A first contactor is used to connect the permanent magnet motor with the driving power supply;

[0031] The second contactor is used to connect the permanent magnet motor and the braking resistor.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] The present invention adopts a dual anti-reversal mechanism of an electromagnetic braking module and a friction braking module. When the pumping pipe reverses, the electromagnetic braking module forms a power generation and energy consumption circuit 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, avoiding the impact wear of traditional brakes, and at the same time reducing the impact torque at the initial stage of reversal, effectively preventing the threaded connection of the pumping rod from loosening.

[0034] Since the electromagnetic braking effect is limited, in the process of offsetting the reversal, the rotation speed of the oil pumping pipe will gradually increase and then fall back. When the speed increases, the present invention drives the axial displacement of the boost ring through the centrifugal force of the counterweight block through the friction brake module, so that the contact pressure between the friction plate and the annular friction ring increases with the increase of the speed. At this time, the reversal torque has been reduced, and the load of the electromagnetic brake module is shared by the friction brake module, which speeds up the braking process, avoids the temperature rise of the brake resistor due to continuous large current exceeding the limit, and extends the service life of the brake resistor. The dual anti-reversal mechanism adapts to the different stages of the reverse braking of the oil pumping pipe, thereby making the reverse braking of the oil pumping pipe more stable.

[0035] The present invention gradually reduces the contact pressure between the friction plate and the annular friction ring during the deceleration stage through the variable pressure friction mechanism, and the braking force is linearly attenuated, ensuring the flexible consumption of residual kinetic energy, avoiding stall shock, and preventing the thread from being subjected to impact torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the overall structure of a double-anti-reverse protection permanent magnet motor ground drive device proposed by the present invention;

[0037] Figure 2 This is a schematic cross-sectional view of a ground drive device for a permanent magnet motor with double anti-reverse protection proposed by the present invention;

[0038] Figure 3 This is a partial structural diagram of a double-anti-reverse protection permanent magnet motor ground drive device proposed by the present invention;

[0039] Figure 4 This is a circuit connection diagram of an electromagnetic brake module in a permanent magnet motor ground drive device with double anti-reverse protection proposed by the present invention;

[0040] Figure 5 This is a structural schematic diagram of a friction brake module in a permanent magnet motor ground drive device with double anti-reverse protection proposed by the present invention;

[0041] Figure 6 This is a schematic cross-sectional view of a friction brake module in a permanent magnet motor ground drive device with double anti-reverse protection proposed by the present invention;

[0042] Figure 7 This is a schematic structural diagram of a variable pressure friction mechanism in a double anti-reverse protection permanent magnet motor ground drive device proposed by the present invention;

[0043] Figure 8 This is a schematic structural diagram of a mounting frame in a ground drive device for a permanent magnet motor with double anti-reverse protection proposed by the present invention;

[0044] Figure 9This is a schematic structural diagram of a fixed frame in a ground drive device for a permanent magnet motor with double anti-reverse protection proposed by the present invention;

[0045] Figure 10 This is a structural schematic diagram of a connecting arm in a centrifugal outward movement state in a double anti-reverse protection permanent magnet motor ground drive device proposed by the present invention;

[0046] Figure 11 This is a schematic diagram of the explosion structure of the connecting shaft of a permanent magnet motor ground drive device with double anti-reverse protection proposed by the present invention.

[0047] In the figure: 1. permanent magnet motor; 11. output shaft; 2. connecting seat; 3. pumping well pipe; 31. pumping rod; 4. electromagnetic brake module; 41. switching circuit; 411. first contactor; 412. second contactor; 42. brake resistor; 5. friction brake module; 51. fixing frame; 52. mounting frame; 521. plate ring; 522. extension plate; 523. connecting shaft; 5231. limit opening; 53. variable pressure friction mechanism; 531. annular friction ring; 532. mounting ring; 5321. limit rod; 533. friction plate; 534. boost ring; 535. connecting arm; 536. counterweight; 537. positioning spring; 538. spiral ramp; 539. matching ramp; 54. brake gear; 55. connecting gear; 56. one-way bearing. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0049] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0050] Reference Figure 1-4 A double anti-reverse protection permanent magnet motor ground drive device includes a permanent magnet motor 1, a connecting seat 2 and a braking system.

[0051] The output shaft 11 of the permanent magnet motor 1 passes through the connecting seat 2 and is fixedly connected to the sucker rod 31. In the prior art, the connection between the motor and the sucker rod is usually through indirect transmission by belts or gears, which has problems such as low transmission efficiency. In this device, the permanent magnet motor 1 and the pumping well pipe 3 are fixedly connected 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 transmission efficiency.

[0052] Reference Figure 1-3 The permanent magnet motor 1 and the oil well pipe 3 are fixedly connected through a connecting seat 2. The connecting seat 2 has an open opening on the side, which is shielded by a grille. The open opening facilitates inspection and maintenance of the interior of the connecting seat 2. At the same time, the air flow can improve the heat dissipation effect of the braking system, and the grille shielding can effectively prevent external debris from entering the interior of the connecting seat 2, avoiding damage to the internal transmission components.

[0053] Reference Figure 1-6 The 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.

[0054] 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.

[0055] 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.

[0056] Reference Figure 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 with the driving power supply. A frequency converter is also provided between the first contactor 411 and the driving power supply. The second contactor 412 is used to connect the permanent magnet motor 1 with the braking resistor 42. Under normal working conditions, the first contactor 411 is closed and the second contactor 412 is disconnected. The permanent magnet motor 1 is connected to the driving power supply to provide power for the sucker rod 31. When the output shaft 11 is detected to be reversed, the control system quickly controls the first contactor 411 to be disconnected and the second contactor 412 to be closed to realize the switching of the windings and ensure the timeliness and accuracy of the braking process. The reversal of the output shaft 11 is detected by a sensor (such as an encoder, a Hall sensor) to detect the reversal signal, and then the opening and closing states of the first contactor 411 and the second contactor 412 are controlled by a PLC or a relay. The sensor and the controller are conventional existing technologies and are not described in detail here. It is easy to realize automatic control.

[0057] Reference Figure 5-11The friction brake module 5 includes a fixed frame 51 fixedly installed in the connecting seat 2, and the fixed frame 51 is fixed to the connecting seat 2 by bolts, wherein the fixed frame 51 is sleeved on the outside of the output shaft 11, and a mounting bracket 52 rotatably sleeved on the output shaft 11 is provided inside the fixed frame 51. A one-way transmission gear set is provided between the mounting bracket 52 and the output shaft 11 so that it only allows 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 mounting bracket 52 does not rotate, so it does not affect the normal operation of the output shaft 11. When the output shaft 11 reverses, the one-way transmission gear set is in In the locked state, the rotation of the output shaft 11 is directly transmitted to the mounting frame 52, driving the mounting frame 52 to rotate. A variable pressure friction mechanism 53 is provided between the mounting frame 52 and the fixed frame 51. The magnitude of the friction braking force is configured according to the reverse speed of the output shaft 11. Under the action of the variable pressure friction mechanism 53, there is a friction resistance between the mounting frame 52 and the fixed frame 51. This resistance ensures that the mounting frame 52 can remain stationary when the output shaft 11 operates normally, and when the output shaft 11 reverses, the mounting frame 52 rotates with the output shaft 11, so that the friction resistance between the mounting frame 52 and the fixed frame 51 acts on the output shaft 11, thereby braking the output shaft 11.

[0058] Since the variable pressure friction mechanism 53 can control the friction braking force according to the reverse speed of the output shaft 11, it can provide different braking forces at different stages of the reversal of the sucker rod 31, provide a larger braking force at the high speed stage to share the load of the electromagnetic brake module 4, and reduce the braking force at the low speed stage to achieve flexible parking.

[0059] Reference Figure 5-11 The mounting frame 52 includes two sheet rings 521, several extension plates 522 and a connecting shaft 523. The two sheet rings 521 are rotatably sleeved on the output shaft 11; several extension plates 522 are equidistantly distributed on the side walls of the sheet rings 521, and the extension plates 522 of the two sheet rings 521 are positioned opposite to each other; 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, several extension plates 522 and the connecting shaft 523 together constitute a frame structure, and the one-way transmission gear set is installed in the frame structure.

[0060] Reference Figure 5-11The one-way transmission gear set includes a brake gear 54 fixedly arranged on the output shaft 11, and the brake gear 54 is located between the two rings 521; a connecting gear 55 is sleeved on the connecting shaft 523 and meshed with the brake gear 54, and a one-way bearing 56 is provided between the connecting gear 55 and the connecting shaft 523. The brake gear 54 rotates with the output shaft 11, and the brake gear 54 can drive the connecting gear 55. It should be noted that under the action of the one-way bearing 56, the brake gear 54 can only drive the connecting gear 55 to rotate in one direction. When the brake 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 brake 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 brake gear 54 directly acts on the mounting frame 52, driving the mounting frame 52 to rotate. The friction resistance generated between the mounting frame 52 and the fixed frame 51 under the action of the variable pressure friction mechanism 53 will act on the brake gear 54, braking the output shaft 11.

[0061] 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 .

[0062] The one-way bearing 56 is configured as follows:

[0063] When the output shaft 11 rotates in the forward direction and the brake gear 54 drives the connecting gear 55 , the connecting gear 55 and the connecting shaft 523 rotate freely.

[0064] When the output shaft 11 rotates in the reverse direction and the brake gear 54 drives the connecting gear 55 , the connecting gear 55 and the connecting shaft 523 are locked.

[0065] , the variable pressure friction mechanism 53 includes two annular friction rings 531 , which are fixedly mounted on the inner top and bottom surfaces of the fixed frame 51 , with the friction surfaces of the two annular friction rings 531 facing each other.

[0066] Reference Figure 5-11 , mounting rings 532 are slidably inserted at both ends of the connecting shaft 523, and 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. Friction force is generated by the contact between the friction plate 533 and the annular friction ring 531, which serves as the braking force of the friction brake module 5. According to Coulomb's friction law, the sliding friction force between objects depends on the friction coefficient of the material contact surface and the positive pressure between the two objects. Therefore, controlling the positive pressure between the friction plate 533 and the annular friction ring 531 can correspondingly change the friction force, thereby enabling the friction brake module 5 to adapt to different braking requirements.

[0067] Reference Figure 5-11, a boost ring 534 is rotatably connected to the connecting shaft 523, and the boost ring 534 is located between the extension plate 522 and the mounting ring 532. A connecting arm 535 is fixedly installed between the boost rings 534 at both ends of the same connecting shaft 523, and a counterweight block 536 is installed at the far end of the connecting arm 535. When the output shaft 11 rotates in the opposite direction, the mounting frame 52 is driven to rotate, and the connecting arm 535 will also rotate with the mounting frame 52 under the centrifugal force of the counterweight block 536, causing the connecting arm 535 to deflect outward. A rotating push structure is provided between the boost ring 534 and the mounting ring 532. When the connecting arm 535 is deflected by the centrifugal force of the counterweight block 536, the mounting ring 532 is driven to produce axial displacement. The axial displacement of the mounting ring 532 will drive the friction plate 533 to squeeze the annular friction ring 531, thereby increasing the positive pressure between the control friction plate 533 and the annular friction ring 531, thereby increasing the friction resistance.

[0068] 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 no external force. Since the connecting arm 535 deflects outwards under the centrifugal force, it will also deflect backwards under the action of inertia. In order to ensure that the connecting arm 535 maintains the trend of deflecting outwards during the rotation process, the deflection and retraction direction of the connecting arm 535 is the direction in which the connecting arm 535 rotates along 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. In this state, the friction plate 533 is in contact with the annular friction ring 531. 31, as the reverse speed of the output shaft 11 increases, the greater the centrifugal force, the greater the positive pressure between the friction plate 533 and the annular friction ring 531, and vice versa. Therefore, when the reverse 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 of the speed, thereby sharing the load of the electromagnetic brake module 4 and accelerating the braking process. After deceleration, the contact pressure between the friction plate 533 and the annular friction ring 531 is gradually reduced, and the braking force is linearly attenuated, ensuring the flexible consumption of residual kinetic energy and avoiding stall shock.

[0069] Reference Figure 5-11The rotating pushing structure includes a spiral bevel 538 provided on the side of the boost ring 534 close to the mounting ring 532. The end face of the mounting ring 532 is provided with a matching bevel 539 adapted to the spiral bevel 538. When the connecting arm 535 is centrifugally deflected, it will drive the boost ring 534 to rotate, causing the spiral bevel 538 and the matching bevel 539 to rotate relative to each other. The distance between the mounting ring 532 and the boost ring 534 increases, and the mounting ring 532 is pushed outward. Due to the long torque of the connecting arm 535, according to the principle of leverage, it can It can provide sufficient driving force for the boost ring 534, and the friction plates 533 at both ends of the connecting shaft 523 move outward synchronously to improve the friction braking effect. It should be noted that in actual applications, although the fixed frame 51, the mounting frame 52 and the friction plate 533 are rigid structures, they will still have slight deformations under the action of external forces. The spiral bevel 538 and the matching bevel 539 can produce an axial drop of 0-2mm, and the axial drop compensation can be used to cause the deformation of each component when the friction plate 533 is axially squeezed by the mounting ring 532.

[0070] In order to improve the stability of the friction force provided between the friction plate 533 and the annular friction ring 531, the number of connecting shafts 523 distributed around the mounting frame 52 is at least two and needs to be evenly distributed. In the embodiment, the number of connecting shafts 523 is four.

[0071] Reference Figure 5-11 The connecting shaft 523 is provided with a radially penetrating limit opening 5231, and a limit rod 5321 is provided in the mounting ring 532 to slide with the limit opening 5231. The limit opening 5231 cooperates with the limit rod 5321 to limit the mounting ring 532, ensuring that only axial sliding can occur between the mounting ring 532 and the connecting shaft 523, and no circumferential rotation occurs, thereby ensuring the stability of the spiral inclined surface 538 and the mating inclined surface 539 when they are pressed together.

[0072] The friction plate 533 is arc-shaped and is arranged concentrically with the annular friction ring 531. The rotation path of the friction plate 533 around the output shaft 11 coincides with the annular friction ring 531, ensuring the contact area between the friction plate 533 and the annular friction ring 531 to improve the friction braking effect.

[0073] The specific working principle of the present invention is as follows:

[0074] In the normal driving stage, the permanent magnet motor 1 directly drives the sucker rod 31 through the output shaft 11 , and the electromagnetic brake module 4 and the friction brake module 5 are in a non-operating state.

[0075] The first contactor 411 in the switching circuit 41 is closed, the second contactor 412 is opened, and the motor winding is connected to the driving power supply.

[0076] In the friction brake module 5 , the one-way transmission gear set is in a free rotation state, the mounting frame 52 is stationary, and the friction plate 533 maintains minimum pressure contact with the annular friction ring 531 .

[0077] When the sucker rod 31 is reversed due to the release of elastic deformation energy or the gravity of crude oil, the electromagnetic brake module 4 and the friction brake module 5 work together in stages to achieve double anti-reverse protection.

[0078] When reversal is triggered, the electromagnetic brake module 4 immediately disconnects the first contactor 411 and closes the second contactor 412, switching the winding of the permanent magnet motor 1 to the braking resistor 42, forming a power generation and energy consumption loop. The permanent magnet motor 1 acts as a generator to convert the reversal mechanical energy into electrical energy, which is dissipated in the form of heat energy through the braking resistor 42, quickly suppressing the torque peak at the initial stage of reversal.

[0079] When the output shaft 11 reverses, the one-way transmission gear set is locked, and the brake gear 54 drives the connecting gear 55 and the mounting frame 52 to rotate as a whole around its own axis. The counterweight block 536 is deflected outward due to centrifugal force, and through the action of the spiral bevel 538 and the matching bevel 539 of the connecting arm 535 and the boost ring 534, the mounting ring 532 is pushed to move axially, thereby increasing the positive pressure between the friction plate 533 and the annular friction ring 531.

[0080] The friction braking force increases linearly with the increase of speed, sharing the load of the electromagnetic brake module 4 and preventing it from exceeding the temperature limit due to continuous large current. When the reverse speed reaches the peak, the centrifugal force of the counterweight block 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 brake module 4 and the friction brake module 5 work together to quickly reduce the speed and shorten the braking time. When the reverse speed decreases, the centrifugal force of the counterweight block 536 decreases, and the positive pressure between the friction plate 533 and the annular friction ring 531 linearly decays, and the braking force gradually decreases, ensuring that the residual kinetic energy is consumed in a flexible manner to avoid damage to the threaded connection caused by the impact of stalling.

[0081] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A double anti-reverse protection permanent magnet motor ground 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) passes through the connecting seat (2) and is fixedly connected to the sucker rod (31); The braking system comprises an electromagnetic braking module (4) and a friction braking module (5), wherein: The friction brake module (5) includes a fixed frame (51) fixedly mounted in the connecting seat (2), a mounting frame (52) rotatably sleeved on the output shaft (11) is provided inside the fixed frame (51), a one-way transmission gear set is provided between the mounting frame (52) and the output shaft (11) to allow only one-way transmission, and a variable pressure friction mechanism (53) is provided between the mounting frame (52) and the fixed frame (51) to configure the magnitude of the friction braking force according to the reverse speed of the output shaft (11); The electromagnetic brake module (4) comprises a switching circuit (41) and a brake resistor (42). When the output shaft (11) is reversed, the switching circuit (41) switches the winding of the permanent magnet motor (1) from the drive end to the brake resistor (42), thereby forming a power generation and energy consumption loop.

2. A double anti-reverse protection permanent magnet motor ground drive device according to claim 1, characterized in that: The permanent magnet motor (1) and the oil well pipe (3) are fixedly connected via a connecting seat (2); a side surface of the connecting seat (2) has an open opening, and the open opening is shielded by a grille.

3. The double anti-reverse protection permanent magnet motor ground drive device according to claim 1, characterized in that: The mounting frame (52) includes: Two sheet rings (521), the two sheet rings (521) are rotatably sleeved on the output shaft (11); A plurality of extension plates (522) are equidistantly distributed on the side wall of the sheet ring (521), and the extension plates (522) of two sheet rings (521) are positioned opposite to each other; The connecting shaft (523) is fixedly mounted between the two corresponding extension plates (522) and is parallel to the output shaft (11).

4. The double anti-reverse protection permanent magnet motor ground drive device according to claim 3 is characterized in that: The one-way transmission gear set comprises a brake gear (54) fixedly arranged on the output shaft (11), and the brake gear (54) is located between two 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 provided between the connecting gear (55) and the connecting shaft (523).

5. The double anti-reverse protection permanent magnet motor ground drive device according to claim 4, characterized in that: 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), and the configuration is as follows: When the output shaft (11) rotates in the forward direction and the brake 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 the reverse direction and the brake gear (54) drives the connecting gear (55), the connecting gear (55) and the connecting shaft (523) are locked.

6. The double anti-reverse protection permanent magnet motor ground drive device according to claim 3, characterized in that: The variable pressure friction mechanism (53) comprises two annular friction rings (531), and the two annular friction rings (531) are fixedly mounted on the inner top surface and inner bottom surface of the fixed frame (51); Mounting rings (532) are slidably inserted at both ends of the connecting shaft (523), and a friction plate (533) is installed at one end of the mounting ring (532) close to the annular friction ring (531); A boost ring (534) is rotatably connected to the connecting shaft (523), and the boost ring (534) is located between the extension plate (522) and the mounting ring (532). A connecting arm (535) is fixedly installed between the boost rings (534) at both ends of the connecting shaft (523), and a counterweight (536) is installed at the far end of the connecting arm (535). A rotational displacement structure is provided between the boost ring (534) and the mounting ring (532), and when the connecting arm (535) is deflected by the centrifugal force of the counterweight (536), the mounting ring (532) is driven to generate 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 when no external force is applied, and at this time, the friction plate (533) is in contact with the surface of the annular friction ring (531).

7. The double anti-reverse protection permanent magnet motor ground drive device according to claim 6, characterized in that: The rotary push structure includes a spiral bevel (538) arranged on the side of the boost ring (534) close to the mounting ring (532), and the end face of the mounting ring (532) is provided with a matching bevel (539) adapted to the spiral bevel (538). The spiral bevel (538) and the matching bevel (539) can generate an axial drop of 0-2 mm.

8. The double 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 opening (5231), and a limiting rod (5321) is provided in the mounting ring (532) and is slidably adapted to the limiting opening (5231).

9. The double anti-reverse protection permanent magnet motor ground drive device according to claim 6, characterized in that: The friction plate (533) is arc-shaped and is arranged concentrically with the annular friction ring (531). The rotation path of the friction plate (533) around the output shaft (11) coincides with the annular friction ring (531).

10. The double anti-reverse protection permanent magnet motor ground drive device according to claim 1, characterized in that: The switching circuit (41) comprises: A first contactor (411) is used to connect the permanent magnet motor (1) with a driving power supply; The second contactor (412) is used to connect the permanent magnet motor (1) and the braking resistor (42).

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