Beam-pumping unit driving system

Abstract

The utility model discloses a beam-pumping unit driving system which comprises a driving device fixing base which is fixed on a pumping unit base through a fastener. A left planetary gear speed reducer, a double-side shaft extension type permanent magnet synchronous motor, a brake assembly and a right planetary gear speed reducer are sequentially arranged on the driving device fixing base from left to right, and a left output shaft of the permanent magnet synchronous motor is connected with an input shaft of the left planetary gear speed reducer through a left coupler. A right output shaft of the permanent magnet synchronous motor is connected with an input shaft of a right planetary gear speed reducer through a right coupler and a first brake assembly; input shafts of the left planetary gear speed reducer and the right planetary gear speed reducer are connected with cranks on the two sides of the pumping unit respectively, the controlled end of the permanent magnet synchronous motor is connected with the motor controller, the motor controller operates in a four-quadrant mode, the stroke frequency is adjusted according to the working condition, and the permanent magnet synchronous motor is controlled to operate with the optimal parameters according to the wellhead load working condition; according to the device, the high-speed permanent magnet synchronous motor is used for replacing a traditional medium-low speed motor, any stroke frequency adjustment is conveniently and rapidly achieved through speed regulation of the motor controller, the size is small, the weight is light, and high-efficiency operation can still be kept under the low load rate.

Description

Technical Field

[0001] The utility model relates to the technical field of oil production equipment, in particular to a beam pumping unit driving system. Background Art

[0002] At present, domestic beam pumping units generally use a medium-low speed asynchronous motor, which is decelerated by a pulley and input into a two-stage reducer with medium-hardened gears. Cranks and counterweights are installed at both ends of the reducer output shaft. The crank rotates to drive the four-bar linkage of the beam pumping unit to operate, thereby realizing the oil production operation of the pumping unit. Figure 1 As shown. The characteristics of the medium and low speed motor and the gearbox with medium hard tooth surface are large size, heavy weight, high cost and high noise. The working characteristics of the oil pump are high starting load and low running load rate, and the characteristics of the asynchronous motor are that the efficiency is greatly reduced as the load rate decreases; at the same time, the belt drive is used between the motor and the reducer, which is inefficient; because the motor is constant speed, when adjusting the pump stroke, it is necessary to replace the motor pulley of different diameters on site to achieve it.

[0003] In summary, the technical defects of the existing configuration are: the motor and reducer are large in size, heavy in weight, and high in cost; the overall operating efficiency of the drive device is low, the noise is loud, and the stroke frequency adjustment is inconvenient. Utility Model Content

[0004] The purpose of the utility model is to provide a walking beam pumping unit drive system, which replaces the traditional medium and low speed motor with a high-speed permanent magnet synchronous motor, and then adjusts the speed through the motor controller to conveniently and quickly realize any stroke adjustment. It is small in size, light in weight, and can still maintain high-efficiency operation at a low load rate; at the same time, the motor servo control technology is used to realize the full posture control during the operation of the pumping unit. During the operation of the pumping unit, the donkey head runs at ultra-low speed at the upper and lower dead points, and runs at a uniform medium and high speed during the up and down process. Thereby increasing the effective stroke, reducing the impact load, greatly improving the pump efficiency, reducing the dynamic liquid level, and increasing the oil well production. The purpose of low stroke, high efficiency and energy-saving operation is achieved.

[0005] The technical solution adopted by the utility model is:

[0006] A walking beam oil pump drive system comprises a driving device fixed base, which is fixed to the oil pump base by fasteners. A left planetary gear reducer, a double-side shaft-extended permanent magnet synchronous motor, a brake assembly and a right planetary gear reducer are arranged on the driving device fixed base from left to right in sequence. A left output shaft and a right output shaft are respectively arranged at the left and right ends of the permanent magnet synchronous motor. The left output shaft of the permanent magnet synchronous motor is connected to the input shaft of the left planetary gear reducer through a left coupling, and the right output shaft of the permanent magnet synchronous motor is connected to the input shaft of the right planetary gear reducer through a right coupling and a first brake assembly; the input shafts of the left planetary gear reducer and the right planetary gear reducer are respectively connected to the cranks on both sides of the oil pump, the controlled end of the permanent magnet synchronous motor is connected to the motor controller, and the motor controller adopts four-quadrant operation, adjusts the stroke frequency according to the working conditions, and controls the permanent magnet synchronous motor to operate with optimal parameters according to the wellhead load conditions.

[0007] The driving device fixed base includes a base plate, on which two vertically opposed positioning plates 1 and 2 are fixed, and positioning plates 1 and 2 are respectively provided with positioning holes 1 and 2, which have the same coaxiality, hole diameter and center height, and the hole axis is parallel to the base plate, and a plurality of threaded holes are evenly distributed along the circumference of positioning holes 1 and 2, and positioning holes 1 and 2 are used for positioning and installing the reducer; it also includes a reinforcing plate, on which the reinforcing plate is provided with upper and lower penetrating grooves 1 and 2, which are respectively penetrated on the positioning plates 1 and 2, and the lower end face of the reinforcing plate is fixed to the upper end face of the base plate; the base plate is provided with fixing holes, and the diameter and position dimensions are consistent with the fixing holes of the original pumping unit reducer bottom plate.

[0008] The driving device fixed base also includes a pair of front reinforcing plates and a pair of rear reinforcing plates. The rear ends of the pair of front reinforcing plates are fixed to the front end surfaces of the reinforcing plates, and the front ends of the pair of rear reinforcing plates are fixed to the rear end surfaces of the reinforcing plates. The base plate, positioning plate one, positioning plate two, reinforcing plates, a pair of front reinforcing plates and a pair of rear reinforcing plates are all made of steel plates and welded as one.

[0009] The permanent magnet synchronous motor is fixed on the fixed base of the driving device through a motor support.

[0010] The permanent magnet synchronous motor adopts a double-side shaft power mode, and its motor output shaft is provided with five sections from left to right, namely a left power docking section, a left support section, a main body section, a left support section and a right power docking section. The diameter of the main body section, the diameter of the left support section and the diameter of the left power docking section gradually decrease in sequence. The step portion formed by the docking of the left end of the main body section with the right end of the left support section is the left bearing abutment portion, and the left power docking section is arranged on the outside of the left end cover of the permanent magnet synchronous motor; the diameter of the right support section is larger than the diameter of the main body section and the diameter of the right power docking section. The step portion formed by the docking of the right end of the right support section with the left end of the right power docking section is the right bearing abutment portion, and the right power docking section is arranged inside the right end cover of the permanent magnet synchronous motor.

[0011] The left power docking section adopts a keyway transmission structure; the right power docking section adopts an internal spline sleeve structure, and the spline sleeve adopts an involute, rectangular or tooth-shaped internal spline.

[0012] A second brake assembly is provided between the permanent magnet synchronous motor and the left planetary gear reducer.

[0013] The first brake assembly and the second brake assembly adopt disc brakes or drum brakes.

[0014] The permanent magnet synchronous motor and the left planetary gear reducer and the right planetary gear reducer are designed as an integrated whole through a housing, and the left planetary gear reducer or the right planetary gear reducer adopts hard tooth surface gear transmission.

[0015] The utility model adopts a high-speed permanent magnet synchronous motor to replace the traditional medium and low speed motor. The left output shaft and the right output shaft are respectively arranged on the left and right sides of the permanent magnet synchronous motor. The left output shaft corresponds to the planetary gear reducer on the left through the left coupling, and the right output shaft corresponds to the planetary gear reducer on the right through the right coupling. The input shafts of the left planetary gear reducer and the right planetary gear reducer are respectively connected to the cranks on both sides of the oil pump, thereby driving the cranks of the oil pump, and then driving the oil pump to operate; the permanent magnet synchronous motor can be adjusted by the motor controller to achieve any stroke adjustment conveniently and quickly, and it is small in size, light in weight, and can still maintain high efficiency operation at low load rates. The whole set of drive devices is integrated on a drive device fixed base, and the connection dimensions of the output shaft and the bottom plate are completely universal with the corresponding dimensions of the reducer output shaft, bottom plate, etc. of the existing oil pump, and can directly replace the original reducer without modifying the existing oil pump component dimensions, thereby reducing equipment investment and operating costs.

[0016] The motor controller can operate in four quadrants, adjust the motor speed to achieve stroke frequency, and realize the full posture control during the operation of the pumping unit. During the operation of the pumping unit, the donkey head runs at ultra-low speed at the upper and lower dead points, and runs at a uniform speed during the up and down process. Thereby increasing the effective stroke, reducing the impact load, greatly improving the pump efficiency, reducing the dynamic liquid level, and increasing the oil well production. The purpose of low stroke frequency, high efficiency and energy-saving operation is achieved.

[0017] This device removes the pulley, and the motor directly drives the planetary gear reducer to improve efficiency.

[0018] In addition, the device adopts planetary gear transmission, which has compact structure, small size, light weight, large transmission ratio, low cost, high efficiency, balanced transmission, low noise and strong impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the background technology of the utility model;

[0020] Figure 2 This is a schematic diagram of the structure of the utility model installed on a beam pumping unit;

[0021] Figure 3 This is a schematic diagram of Embodiment 1 of the present utility model;

[0022] Figure 4 This is a schematic diagram of the second embodiment of the present utility model;

[0023] Figure 5 This is a schematic diagram of the third embodiment of the present utility model;

[0024] Figure 6 This is a cross-sectional view of the fixed base of the drive device of the utility model;

[0025] Figure 7 This is a top view of the fixed base of the drive device of the utility model;

[0026] Figure 8 This is a left view of the fixed base of the drive device of the utility model;

[0027] Fig. 9 It is a schematic diagram of the structure of the output shaft of the motor of the utility model.

[0028] Pumping unit base 1, driving device fixed base 2, crank 3, left planetary gear reducer (hereinafter referred to as "left planetary box") 4, left coupling 5-1, right coupling 5-2, permanent magnet synchronous motor 6, first brake assembly 7-1, second brake assembly 7-2, right planetary gear reducer 8 (hereinafter referred to as "right planetary box"), motor controller 9, fastener 10, motor support 11. DETAILED DESCRIPTION

[0029] like Figure 1 As shown, the utility model includes a drive device fixed base 2, which is fixed to the oil pump base 1 by fasteners 10, and the drive device fixed base 2 is provided with a left planetary gear reducer 4 (hereinafter referred to as "left planetary box"), a permanent magnet synchronous motor 6, a first brake assembly 7-1 and a right planetary gear reducer 8 (hereinafter referred to as "right planetary box") from left to right. All of the above devices are integrated and installed on the drive device fixed base 2, and the lower end surface of the drive device fixed base 2 is connected to the oil pump base 1.

[0030] The permanent magnet synchronous motor 6 is a high-speed, liquid-cooled, double-sided output motor. The left and right ends of the permanent magnet synchronous motor 6 are respectively provided with a left output shaft and a right output shaft. The permanent magnet synchronous motor 6 is used as a power source, and the speed can be adjusted by the motor controller 9 to conveniently and quickly realize any stroke adjustment. The permanent magnet synchronous motor 6 is small in size, light in weight, and can still maintain high-efficiency operation at a low load rate. The motor controller 9 can operate in four quadrants, adjust the stroke according to the working conditions, and control the motor to operate with optimal parameters according to the wellhead load conditions. The left output shaft of the permanent magnet synchronous motor 6 is connected to the input shaft of the left planetary gear reducer 4 through the left coupling 5-1, and the right output shaft of the permanent magnet synchronous motor 6 is connected to the input shaft of the right planetary gear reducer 8 through the right coupling 5-2 and the first brake assembly 7-1. The permanent magnet synchronous motor 6 can be connected to the left planetary gear reducer 4 and the right planetary gear reducer 8 through a coupling, a spline (sleeve), or a tightening sleeve, eliminating the traditional pulley. The permanent magnet synchronous motor 6 is connected to the input shaft of two hard-toothed, high-speed-ratio planetary gear reducers, with high transmission efficiency, compact structure, small size, light weight, low purchase cost, and low noise. In addition, the motor controller adjusts the stroke according to the working conditions and controls the permanent magnet synchronous motor to operate with optimal parameters according to the wellhead load conditions. The controller uses the motor servo control technology to achieve full-process posture control during the operation of the pumping unit. During the operation of the pumping unit, the donkey head runs at ultra-low speed at the upper and lower dead points, and runs at a uniform speed during the up and down process. Thereby increasing the effective stroke, reducing the impact load, greatly improving the pump efficiency, reducing the dynamic liquid level, and increasing the oil well production. The purpose of low stroke, high efficiency, and energy-saving operation is achieved.

[0031] The left planetary gear reducer 4 and the right planetary gear reducer 8 adopt hard tooth surface gear transmission and high speed ratio design to meet the high speed input of the motor and the low speed output required by the working condition of the oil pump. The shells of the two planetary gear reducers of the same model are first rough-machined respectively, and the shaft holes are left with machining allowances. The two are fixed as a whole with the base, and then clamped on the machine tool for overall processing to ensure that the coaxiality of the shaft holes, especially the output shaft holes, is consistent. After the two planetary gear reducers of the same model are assembled, the gears and shafts are adjusted using tooling to ensure that the output shaft keyways of the two planetary gear reducers are completely aligned, and fixed and marked. After the permanent magnet synchronous motor 6 is installed, the two keyways are always aligned. The output shafts of the left planetary gear reducer 4 and the right planetary gear reducer 8 are respectively connected to the cranks 3 on both sides of the oil pump, and the controlled end of the permanent magnet synchronous motor 6 is connected to the motor controller 9. The motor controller 9 drives the permanent magnet synchronous motor 6 to operate, driving the planetary reducer to operate, and the output shafts of the two planetary reducers respectively drive the two cranks 3 of the oil pump to operate, thereby driving the oil pump to operate. When maintenance is required, the brake assembly can be operated to stop the oil pump.

[0032] The driving device fixed base includes a base plate 21, on which two vertically opposed positioning plates 1 22 and 23 are fixed, which are fixed by welding. Positioning plates 1 22 and 23 are respectively provided with positioning holes 1 24 and 25. Positioning holes 1 24 and 25 have the same coaxiality, the same aperture, and the same center height, and the hole axis is parallel to the base plate 21. A plurality of threaded holes 26 are evenly distributed along the circumference of positioning holes 1 24 and 25. Positioning holes 1 24 and 25 are used for positioning and installing the reducer. When machining the threaded bottom hole, the positioning hole axis is used to As a processing reference, it ensures that the parallelism and symmetry of the threaded hole 26 and the positioning hole meet the design requirements; it also includes a reinforcing plate 27, which is welded on the base plate 21, and is provided with a card slot 1 and a card slot 2 that penetrate up and down, and the card slot 1 and the card slot 2 are respectively penetrated on the positioning plate 1 22 and the positioning plate 2 23, and the lower end face of the reinforcing plate 27 is fixed to the upper end face of the base plate 21; the base plate 21 is provided with a fixing hole 28, and the fixing hole 28 is a light hole, and the diameter and position dimensions are consistent with the original fixing hole 28 of the base plate of the oil pump reducer, and can be directly installed on the base of the oil pump.

[0033] It also includes a pair of front reinforcing plates 29 and a pair of rear reinforcing plates 210, the rear ends of the pair of front reinforcing plates 29 are fixed to the front end surface of the reinforcing plate 27, and the front ends of the pair of rear reinforcing plates 210 are fixed to the rear end surface of the reinforcing plate 27. The base plate 21, the first positioning plate 22, the second positioning plate 23, the reinforcing plate 27, the pair of front reinforcing plates 29 and the pair of rear reinforcing plates 210 are all made of steel plates, which are welded as a whole to ensure the overall structural strength. After the welding is completed, welding stress relief measures are taken, which can be various stress relief measures such as heat treatment, vibration, and natural aging.

[0034] The permanent magnet synchronous motor 6 is fixed on the driving device fixed base 2 via a motor support 11 .

[0035] The permanent magnet synchronous motor 6 adopts a double-side shaft power mode, and its motor output shaft 61 is provided with five sections from left to right, namely a left power docking section 611, a left support section 612, a main body section 613, a right support section 614 and a right power docking section 615. The diameters of the main body section 613, the left support section 612 and the left power docking section 611 gradually decrease in sequence. The step portion formed by the docking of the left end of the main body section 613 and the right end of the left support section 612 is the left bearing abutment portion, and the left power docking section 611 is arranged on the outside of the left end cover of the permanent magnet synchronous motor; the diameter of the right support section is larger than the diameter of the main body section 613 and the diameter of the right power docking section 615. The step portion formed by the docking of the right end of the right support section and the left end of the right power docking section 615 is the right bearing abutment portion, and the right power docking section 615 is arranged inside the right end cover of the permanent magnet synchronous motor.

[0036] The left power docking section 611 adopts a keyway transmission structure; the right power docking section 615 adopts an internal spline sleeve structure, and the spline sleeve adopts an involute, rectangular or tooth-shaped internal spline.

[0037] The output shaft 61 is arranged at the center of the motor 6, and positioning holes located on the same horizontal line are arranged on the left motor end cover and the right motor end cover of the motor 6, and positioning rings are arranged on the inner and outer edges of the positioning holes, respectively. The positioning rings are used to clamp against one side end face of the corresponding bearing, and the other side end face of the bearing is connected to the corresponding left end face of the main section 6131 and the right end face of the right support section. In fact, an annular groove is formed between the left end face of the main section 6131 and the left motor end cover, which is used to clamp the bearing at the left end, and then further positioned by the positioning ring to ensure that the output shaft will not be offset during operation. Similarly, an annular groove is formed between the right end face of the right support section and the inner side of the right motor end cover, which is used to clamp the bearing at the right end, and then further positioned by the positioning ring.

[0038] In addition, the left power docking section 6113 adopts a keyway transmission structure and the right power docking section 6155 adopts an internal spline sleeve 6 structure as a transmission method, and then matches the reduction boxes on the left and right sides of the docking, ensuring that the device is easy to install and easy and quick to operate.

[0039] A second brake assembly 7-2 is provided between the permanent magnet synchronous motor 6 and the left planetary gear reducer 4. The first brake assembly 7-1 and the second brake assembly 7-2 are disc brakes or drum brakes.

[0040] The permanent magnet synchronous motor 6 and the left planetary gear reducer 4 or the right planetary gear reducer 8 are designed to be integrated through a housing.

[0041] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0042] Embodiment 1

[0043] like Figure 2 As shown, the utility model includes a driving device fixed base 2, which is fixed to the oil pump base 1 by fasteners 10. The driving device fixed base 2 is provided with a left planetary gear reducer 4, a permanent magnet synchronous motor 6, a brake assembly and a right planetary gear reducer 8 from left to right. The permanent magnet synchronous motor 6 is fixed to the driving device fixed base 2 by a motor support 11; the left and right ends of the permanent magnet synchronous motor 6 are respectively provided with a left output shaft and a right output shaft, the left output shaft of the permanent magnet synchronous motor 6 is connected to the input shaft of the left planetary gear reducer 4 through a left coupling 5-1, and the right output shaft of the permanent magnet synchronous motor 6 is connected to the input shaft of the right planetary gear reducer 8 through a right coupling 5-2 and a first brake assembly 7-1; the input shafts of the left planetary gear reducer 4 and the right planetary gear reducer 8 are respectively connected to the cranks 3 on both sides of the oil pump, and the controlled end of the permanent magnet synchronous motor 6 is connected to the motor controller 9.

[0044] The left planetary box 4 and the right planetary box 8 in this embodiment are symmetrically arranged on the left and right sides of the permanent magnet synchronous motor 6. The device adopts a high-speed permanent magnet synchronous motor 6 as a power source, and drives the left and right planetary box input shafts to rotate through the couplings at both ends, and outputs after the left and right planetary boxes are decelerated. The left and right planetary box output shafts respectively drive the left and right cranks 3 to operate, thereby driving the oil pump to operate. The brake assembly installed on the right planetary box input shaft can stop the oil pump when needed.

[0045] The high-speed permanent magnet synchronous motor 6 replaces the asynchronous motor. It is small in size, light in weight, and can still maintain high-efficiency operation at low load rates. The motor controller 9 can be used to adjust the speed to achieve any stroke adjustment conveniently and quickly. The pulley drive is eliminated and a planetary gear drive is adopted. It has high efficiency, compact structure, small size, light weight, low purchase cost and low noise. All equipment is integrated on a drive device fixed base 2. The overall drive device is compatible with the traditional reducer interface size and can directly replace the original reducer and install it on the pumping unit without modifying the size of the existing pumping unit parts.

[0046] Embodiment 2

[0047] The difference from Example 1 is that the permanent magnet synchronous motor 6 is integrated with the left planetary box, the shells of the two are connected as a whole through a flange and a fastener 10, the output shaft of the permanent magnet synchronous motor 6 is connected to the input shaft of the left planetary box through a spline shaft (sleeve), and the permanent magnet synchronous motor 6 is fixed to the fixed base 2 of the drive device through a motor support 11 with a shock absorbing function.

[0048] Embodiment 3

[0049] The difference from Example 1 is that a second brake assembly 7-2 is added between the permanent magnet synchronous motor 6 and the left planetary box, the second brake assembly 7-2 is installed on the input shaft of the left planetary box, the permanent magnet synchronous motor 6 is connected to the left planetary box through the left coupling 5-1, and the permanent magnet synchronous motor 6 is fixed to the fixed base 2 of the drive device through the motor support 11.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.

Claims

1. A beam pumping unit drive system, characterized in that: It includes a driving device fixed base, which is fixed to the oil pumping unit base by fasteners. The driving device fixed base is provided with a left planetary gear reducer, a double-side shaft-extended permanent magnet synchronous motor, a brake assembly and a right planetary gear reducer from left to right in sequence. The left and right ends of the permanent magnet synchronous motor are respectively provided with a left output shaft and a right output shaft. The left output shaft of the permanent magnet synchronous motor is connected to the input shaft of the left planetary gear reducer through a left coupling, and the right output shaft of the permanent magnet synchronous motor is connected to the input shaft of the right planetary gear reducer through a right coupling and a first brake assembly; the input shafts of the left planetary gear reducer and the right planetary gear reducer are respectively connected to the cranks on both sides of the oil pumping unit, the controlled end of the permanent magnet synchronous motor is connected to the motor controller, and the motor controller adopts four-quadrant operation, adjusts the strokes according to the working conditions, and controls the permanent magnet synchronous motor to operate with optimal parameters according to the wellhead load conditions.

2. The beam pumping unit drive system according to claim 1, characterized in that: The driving device fixed base includes a base plate, on which two vertically opposed positioning plates 1 and 2 are fixed, and positioning plates 1 and 2 are respectively provided with positioning holes 1 and 2, which have the same coaxiality, hole diameter and center height, and the hole axis is parallel to the base plate, and a plurality of threaded holes are evenly distributed along the circumference of positioning holes 1 and 2, and positioning holes 1 and 2 are used for positioning and installing the reducer; it also includes a reinforcing plate, on which the reinforcing plate is provided with upper and lower penetrating grooves 1 and 2, which are respectively penetrated on the positioning plates 1 and 2, and the lower end face of the reinforcing plate is fixed to the upper end face of the base plate; the base plate is provided with fixing holes, and the diameter and position dimensions are consistent with the fixing holes of the original pumping unit reducer bottom plate.

3. The beam pumping unit driving system according to claim 2, characterized in that: The driving device fixed base also includes a pair of front reinforcing plates and a pair of rear reinforcing plates. The rear ends of the pair of front reinforcing plates are fixed to the front end surfaces of the reinforcing plates, and the front ends of the pair of rear reinforcing plates are fixed to the rear end surfaces of the reinforcing plates. The base plate, positioning plate one, positioning plate two, reinforcing plates, a pair of front reinforcing plates and a pair of rear reinforcing plates are all made of steel plates and welded as one.

4. The beam pumping unit driving system according to claim 1, characterized in that: The permanent magnet synchronous motor is fixed on the fixed base of the driving device through a motor support.

5. The beam pumping unit driving system according to claim 1, characterized in that: The permanent magnet synchronous motor adopts a double-side shaft power mode, and its motor output shaft is provided with five sections from left to right, namely a left power docking section, a left support section, a main body section, a right support section and a right power docking section. The diameter of the main body section, the diameter of the left support section and the diameter of the left power docking section gradually decrease in sequence. The step portion formed by the docking of the left end of the main body section with the right end of the left support section is the left bearing abutment portion, and the left power docking section is arranged on the outside of the left end cover of the permanent magnet synchronous motor; the diameter of the right support section is larger than the diameter of the main body section and the diameter of the right power docking section. The step portion formed by the docking of the right end of the right support section with the left end of the right power docking section is the right bearing abutment portion, and the right power docking section is arranged inside the right end cover of the permanent magnet synchronous motor.

6. The beam pumping unit driving system according to claim 5, characterized in that: The left power docking section adopts a keyway transmission structure; the right power docking section adopts an internal spline sleeve structure, and the spline sleeve adopts an involute, rectangular or tooth-shaped internal spline.

7. The beam pumping unit driving system according to claim 1, characterized in that: A second brake assembly is provided between the permanent magnet synchronous motor and the left planetary gear reducer.

8. The beam pumping unit driving system according to claim 7, characterized in that: The first brake assembly and the second brake assembly adopt disc brakes or drum brakes.

9. The beam pumping unit driving system according to claim 8, characterized in that: The permanent magnet synchronous motor and the left planetary gear reducer and the right planetary gear reducer are designed as an integrated whole through a housing, and the left planetary gear reducer or the right planetary gear reducer both adopt hard tooth surface gear transmission.

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