Energy-saving design method based on non-circular gear transmission and beam-pumping unit

Abstract

The application discloses an energy-saving design method based on non-circular gear transmission and a beam-pumping unit, and the energy-saving design method comprises the following steps: 1, fitting the suspension point load data into an initial crank angular velocity equation through a Fourier series, introducing the equation into a beam-pumping unit model, and obtaining a first crank load and a first crank angular velocity equation through simulation; 2, introducing the first crank angular velocity equation into the beam-pumping unit model, obtaining a second crank load through simulation, calculating motor energy consumption, judging whether the preset energy-saving rate is met according to the motor energy consumption, if the preset energy-saving rate is met, taking the first crank angular velocity equation as a final crank angular velocity equation, and turning to step 4; 3, if the preset energy-saving rate is not met, adjusting the first crank angular velocity equation, and returning to step 2 until the preset energy-saving rate is met; and 4, obtaining a non-circular gear pitch curve according to the final crank angular velocity equation. The application replaces a traditional cylindrical gear transmission reducer with a non-circular gear transmission reducer, so that energy-saving is realized.

Description

Technical Field

[0001] This invention belongs to the field of non-circular gear design, specifically relating to an energy-saving design method based on non-circular gear transmission and a beam pumping unit. Background Technology

[0002] Currently, mechanical oil recovery is the most prevalent method of oil extraction globally, with beam pumping units widely used in major oilfields both domestically and internationally due to their simple structure, strong field adaptability, and ease of maintenance. In response to national carbon peaking and carbon neutrality policies, oilfield production needs to address the issue of low efficiency in the utilization of electricity. Improving the efficiency of beam pumping units has been a widely discussed and important topic.

[0003] Low motor load rate is the main reason for energy consumption of beam pumping units. Although traditional beam pumping units have a wide range of applications, they use cylindrical gear transmission, which has large load characteristics and causes the characteristic of "big horse pulling a small cart", resulting in unnecessary energy consumption. In response to this problem, scholars at home and abroad have conducted a lot of research. In terms of structural optimization: Geng Yan et al. [1] analyzed the main energy consumption sources of the pump system and proposed the energy-saving technology direction of adding energy-saving devices to traditional oil extraction pump equipment; Zhou Yong et al. [2] designed a flywheel energy storage system suitable for beam pumping units and verified the feasibility of the energy storage system; Guo Zhechong et al. [3] designed a beam pumping unit that can adjust the balance state according to the oil well working parameters. After the balance state is adjusted irregularly, the energy-saving effect of the equipment in long-term operation is obvious; Yang Xiaogang et al. [4] developed a suspended balance beam pumping unit, which reduced the phase of the sucker rod. Regarding deformation values, the filling factor and displacement factor of the pumping unit were improved, extending the service life of the sucker rod and the pumping unit, and achieving the overall requirements of high efficiency and low energy consumption. In terms of new structural design: Zhang Chunyou et al. [5] proposed a new mechanical-hydraulic hybrid power system energy-saving scheme by comparing energy-saving schemes of different hydraulic systems; Mu Fei et al. [6] provided a basis for improving the quality and efficiency of mechanical pumping equipment by applying a new tower-type pumping unit to lift equipment from mechanical wells, and achieved advanced tower machine operation indicators and significant energy-saving effect; Xu Lihong et al. [7] adopted a pumping unit direct drive motor to directly drive the walking beam pumping unit four-link machine. The transmission mechanism reduces the number of gearboxes and belt drives, making the system simpler and significantly improving mechanical efficiency. Meng Qingfeng et al. [8] developed a non-stop intermittent oil extraction technology for pumping units, which has the advantages of high working efficiency and reduced energy consumption. Kong Hongfang et al. [9] designed an intelligent balancing device for pumping units, which can keep the pumping unit in the best operating state when the downhole load changes, thus achieving the goal of energy saving and consumption reduction. Cui Jianlun et al.

[10] developed a gear and rack hybrid transmission reducer, which improved the motor load rate and efficiency by reducing the power configuration of the pumping unit motor, thus achieving the goal of energy saving and consumption reduction. Li Sihai et al.

[11] By controlling speed and acceleration, the system achieves flexible optimization operation. Optimization can improve motor efficiency, reduce load mutations, eliminate power generation intervals, and optimize the operating state of the rod and tube pump, thus achieving energy saving for the pumping unit. Zhang Li et al.

[12] studied the balancing method and energy consumption of the pumping unit, proposed the design basis and method of the balancing adjustment device, designed an automatic monitoring system, and realized automatic adjustment of frequency conversion speed regulation and optimal stroke. Wang Xiaojun et al.

[13] designed an automatic adjustment balancing device for the pumping unit, that is, before modification, a movable slider is set at the tail of the pumping unit, and the swing of the pendulum replaces the linear displacement of the moving slider. And the balance weight of the pendulum is driven so that the balancing torque of the pumping unit beam can be dynamically adjusted, and finally the balance of the pumping unit system can be adjusted. The balance state of the pumping unit can be achieved without stopping the machine, reducing energy consumption and improving the balancing adjustment accuracy.Shi Maohuan et al.

[14] used a permanent magnet composite motor as the power source to replace the induction motor, belt and gearbox, and directly drive the four-bar linkage mechanism. This type of pumping unit changed the conventional beam pumping unit's long power transmission chain and low transmission efficiency, improved the system efficiency, and avoided replacing the gearbox lubricating oil and belt, thus achieving the purpose of energy saving and safety. Through field test application, the power saving rate can reach 30%, and the energy saving effect is significant. Liu

[15] calculated the optimal voltage of the current load through a genetic algorithm, thereby generating an energy saving effect.

[0004] In summary, the existing energy-saving design schemes for oil pumping units mainly achieve this by adding energy-saving devices to the original structure and designing new oil pumping units, but the reliability of the oil pumping units needs to be improved.

[0005] In the prior art, an invention patent with application publication number CN101463889A discloses a non-circular gearbox and its transmission mechanism, which consists of a non-circular gearbox, a low-speed motor, and a sprocket system or pulley system. It is a non-uniform speed ratio combined transmission mechanism. Its output torque and output speed are adapted to the load variation of the host machine, and its use in various mechanical equipment requiring non-uniform speed ratio transmission can achieve significant energy savings. The pitch curve shape, geometry, and initial position parameters of the non-circular gear are determined after optimization design based on the load variation of the host machine, the continuity of the pitch curve, and the manufacturability. When the non-circular gear is powered by a cylindrical gear system or a cylindrical gear planetary gear system, it can form various forms of non-circular gearboxes. This invention, by removing the original reducer, pulleys, and motor from a conventional beam pumping unit and installing a non-circular gearbox and its transmission mechanism, can form an energy-saving beam pumping unit.

[0006] Another invention patent application, CN112797123A, discloses an automatic reversing reducer with a composite transmission of non-circular gears and planetary mechanisms. It includes a housing and a reversing assembly housed within the housing. The reversing assembly includes an input group, a sun gear, and a planet carrier. The input group includes a first sprocket and a first non-circular gear mounted on an input shaft. The first sprocket meshes with a second sprocket to drive the sun gear to rotate at a constant speed. The first non-circular gear meshes with the second non-circular gear to drive the planet carrier to rotate at a periodic speed. The planet carrier is connected to a planetary gear and moves relative to it. The planetary gear meshes between an internal gear rotary support and the sun gear. The internal gear rotary support is fixedly connected to an output shaft to drive the output shaft to periodically change its output. This invention is based on an automatic reversing mechanism of a non-circular gear differential gear train. This structure offers smooth transmission, high efficiency, strong energy saving, and high component interchangeability and easy disassembly.

[0007] Although the above scheme mentions non-circular gear transmission, in actual application, the basic shape of its gear transmission is limited by the non-circular gear pitch curve function expression. The existing non-circular gear pitch curve function expression is difficult to apply directly to beam pumping units. It is necessary to select the non-circular gear transmission pitch curve function expression multiple times according to the actual situation, which requires a high level of experience from the designers, and it is difficult to find an ideal non-circular gear pitch curve function expression.

[0008] The list of references mentioned above is as follows: [1] Geng Yan. Analysis and analysis on energy-saving technology of oilfield pumping unit [J]. Equipment management and maintenance, 2022(21):159-160. [2] Zhou Yong, Chen Xiangyu, Jian Lin, et al. Design and experiment of flywheel energy storage system for swimming beampumping machine [J]. Energy Storage Science and Technology, 2022, 11(20): 593-599. [3] Guo Zhechong, Ding Peng, Zhang Zhengyi, et al. Technology and application of the new front-facing and rear-balanced energy-saving extraction machine [J]. Equipment management and maintenance, 2021(17):139-140. [4] Yang Xiaogang, Zeng Xingchang, Zhang Xiaolong, et al. Development of suspension weight balance swimming beampumping machine [J]. Mechanical Manufacturing, 2021, 59(09): 36-40. [5] Zhang Chunyou, Gao Xiaolong. Simulation and experimental study of energy-saving system of swimming beam pumping machine [J]. Automation in Manufacturing Industry, 2023, 45(07): 111-116. [6] Mu Fei. Research on energy-saving technology of new tower-type pumping unit [J]. Petroleum and petrochemical energy saving, 2023, 13(02): 6-10. [7] Xu Lihong, Li Qingzhu, Liu Shiyu, et al. Field application and effect of direct drive motor of pumping machine [J]. Petroleum and petrochemical energy saving, 2022, 12(07): 45-49. [8] Meng Qingfeng. Non-stop intermittent oil recovery technology of oil pumping unit and its application[J]. Chemical Engineering and Equipment, 2022(04):139-140. [9] Kong Hongfang, Zhou Xiaodong, You Lihong. Research and application of intelligent energy-saving technology of swimming beampumping machine [J]. Technical Supervision of the Petroleum Industry, 2020, 36(12):52-54+62.

[10] Cui Jianlun, Shi Chengjiang. Application analysis of hybrid driver reducer in energy saving of pumping unit [J]. New Technology and New Process, 2019(07):22-25.

[11] Li Sihai. Application of energy-saving technology for pumping unit [J]. Chemical Engineering and Equipment, 2023(05):134-135+141.

[12] Zhang Li, Han Mengyang. Research and design of energy-saving control system for digital automatic balancing pump[J]. Mechanical and Electronic, 2019, 37(10):46-49+54.

[13] Wang Xiaojun, Zhen Hao, Li Hao. Design of self-balancing system of energy-saving conventional beam pumping unit [J]. Adhesive, 2020, 41(01): 172-174+188.

[14] Shi Mao-huan, Zhang Zhenshun, Zhou Heping, et al. Experimental application of direct-drive swimming beampumping machine[J]. Broken block oil and gas field, 2019, 26(01):134-136.

[15] LiuXinping,XuJunpeng.TheMethodofEnergySavinginBeamPumpingUnitBasedonGeneticAlgorithm[AASRIProcedia].20121:441-447. Summary of the Invention A brief overview of embodiments of the invention is provided below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0009] According to one aspect of this application, an energy-saving design method based on non-circular gear transmission is provided, comprising: Step 1: Fit the suspension load data to the initial crank angular velocity equation using Fourier series, import the initial crank angular velocity equation into the walking beam pumping unit model, obtain the first crank load through the original structure simulation, and obtain the first crank angular velocity equation based on the first crank load. Step 2: Import the first crank angular velocity equation into the walking beam pumping unit model, obtain the second crank load through simulation, calculate the motor load based on the second crank load, calculate the motor energy consumption based on the motor load, and determine whether the preset energy saving rate is met based on the motor energy consumption. If it is met, the first crank angular velocity equation is used as the final crank angular velocity equation, and proceed to step 4. The motor load is calculated by directly dividing the crank load by the total transmission ratio of the belt drive and gear drive. Since the overall transmission ratio is variable after using non-circular gears, the motor load is obtained by dividing the discrete points of the crank load by the discrete points of the variable transmission ratio. In addition, the motor energy consumption is calculated based on the motor load by a quantitative equation fitted by the motor torque data and the corresponding current energy consumption data. The equation expression is: current I = 0.00007314*M^2 + 0.02149*M + 17.37 (I is the motor current, M is the motor torque).

[0010] Furthermore, whether the preset energy-saving rate is met, i.e., energy-saving verification, is achieved by comparing the existing structure with the original structure. Therefore, the same number of discrete points can be used for comparison. The preset energy-saving rate is the expected energy-saving rate. Meeting the preset energy-saving rate means selecting the curve with the highest energy-saving rate among the curves that meet the energy-saving rate requirements, which is the final curve that needs to be designed.

[0011] Step 3: If the condition is not met, adjust the first crank angular velocity equation and return to Step 2. Import the adjusted first crank angular velocity equation into the beam pumping unit model until the preset energy saving rate is achieved. The corresponding adjusted first crank angular velocity equation is then used as the final crank angular velocity equation. Specifically, adjusting the first crank angular velocity equation involves adjusting the phase angle, the upper and lower limits of the crank angular velocity fluctuation, and the order of the trigonometric function in the crank angular velocity equation. This step is used to select a balance between stability and energy saving rate. Step 4: Obtain the non-circular gear pitch curve based on the final crank angular velocity equation. That is, substitute the final crank angular velocity equation corresponding to the lowest energy consumption into the non-circular gear pitch curve and angular velocity equation to obtain the non-circular gear driving gear pitch curve.

[0012] In this context, the crank angular velocity represents the transmission speed of the driven gear in a non-circular gear transmission, while the driving gear rotates at a constant speed. The angular velocity of the driving gear is (36*π / 180) rad / s.

[0013] The present invention adopts the above-mentioned scheme. The design principle of the non-circular gear pitch curve is to fit the crank load curve by adjusting the transmission ratio curve. Theoretically, the change of the transmission ratio curve can perfectly match the crank load curve, but due to the constraints of gear strength and processing technology, the transmission ratio must be designed within a certain range.

[0014] Furthermore, in step 1, the suspension point load data is obtained using a load sensor, and the suspension point load equation is fitted using the suspension point load. The walking beam pumping unit model is established by importing a three-dimensional model of the walking beam pumping unit into ADAMS. The establishment of the three-dimensional model of the walking beam pumping unit is existing technology and will not be detailed here. The crank load is extracted by simulating the walking beam pumping unit model and combining it with the structure of the walking beam pumping unit.

[0015] Considering the large peak and fluctuation of the crank load, the optimal pitch curve cannot be obtained through a single fitting. Therefore, it is necessary to combine the crank load with the crank angular velocity fitting to obtain the crank angular velocity equation. Then, the pitch curve of the driving wheel is calculated, and the crank angular velocity is substituted again to obtain the optimal pitch curve through iterative iteration. The original structure of the motor load has two peak values. In order to reduce the peak and fluctuation amplitude of the motor load, the crank angular velocity under non-circular gear transmission is input into the walking beam pumping unit model (ADAMS) to simulate the motor load. At the same time, the counterweight is adjusted to make the two peak values ​​closer.

[0016] During the design process, the crank angular velocity is minimized as much as possible at the peak of the crank load while the crank is decelerating. When the low-speed end and the deceleration end of the crank coincide with the peak of the crank load, the peak motor load can be reduced. The initial crank angular velocity equation is obtained by preliminary fitting of the crank angular velocity using Fourier series. After inputting the initial crank angular velocity equation into the ADAMS walking beam pumping unit model, the first crank load is obtained through simulation.

[0017] Since the external torque caused by the rotational inertia of the gears is very small compared to the crank torque, it can be almost ignored. Therefore, the motor load can be obtained by directly dividing the crank load by the transmission ratio. Then, the motor current energy consumption can be obtained according to the formula for motor current and motor torque.

[0018] As can be seen from the above analysis, when other factors remain unchanged, the energy consumption of the motor depends on the crank angular velocity. By optimizing the phase angle and change curve of the crank angular velocity, and by adjusting the counterweight, and repeating the above simulation steps, the crank angular velocity corresponding to the lowest motor energy consumption can be obtained.

[0019] Specifically, the crank angular velocity equation is expressed in terms of time t as follows: ω(t)=-((1379*cos((π*t) / 5)) / 10000-π / 5- (9629*cos((2*π*t) / 5)) / 100000-(4501*cos((3*π*t) / 5)) / 100000-(7109*sin((π* t) / 5)) / 100000+(3997*sin((2*π*t) / 5)) / 50000+(1323*sin((3*π*t) / 5)) / 100000).

[0020] The formula for crank angular velocity with respect to angle e is as follows: π / 5+(9629*cos(2*e)) / 100000+(4501*cos(3*e)) / 100000-(3997*sin(2*e)) / 50 000-(1323*sin(3*e)) / 100000-(1379*cos(e)) / 10000+(7109*sin(e)) / 100000.

[0021] The non-circular gear pitch curve is obtained based on the final crank angular velocity equation. Specifically, the final crank angular velocity equation is substituted into equation r1 to obtain the non-circular gear pitch curve. Equation r1 is expressed as follows: r1=200*ω(t) / ((36*π / 180)+ω(t)).

[0022] Specifically, the final non-circular gear pitch curve is expressed as follows: r1=(40*π+(9629*cos(2*e)) / 500+(4501*cos(3*e)) / 500-(3997*sin(2*e)) / 2 50-(1323*sin(3*e)) / 500-(1379*cos(e)) / 50+(7109*sin(e)) / 500) / ((2*π) / 5 +(9629*cos(2*e)) / 100000+(4501*cos(3*e)) / 100000-(3997*sin(2*e)) / 500 00-(1323*sin(3*e)) / 100000-(1379*cos(e)) / 10000+(7109*sin(e)) / 100000) R1 is the driving gear pitch curve of a non-circular gear. If the center distance is 200, then the driven gear pitch curve is r2 = 200 - r1.

[0023] According to another aspect of this application, a walking beam pumping unit based on non-circular gear transmission is provided, comprising a walking head, a walking beam, a connecting rod, a crank, a non-circular gear pair, and a planetary gear train connected in sequence. The walking beam pumping unit employs a non-circular gear transmission reducer. The first stage of the non-circular gear transmission reducer adopts a planetary gear train transmission with a fixed large transmission ratio, and the second stage adopts a non-circular gear transmission with a variable transmission ratio. The matching degree between the transmission ratio and the crank load is increased by designing the pitch curve of the second-stage non-circular gear. The pitch curve of the second-stage non-circular gear is implemented using the aforementioned energy-saving design method.

[0024] To address the energy-saving challenges of existing beam pumping units, this invention proposes an energy-saving design method for beam pumping units based on non-circular gear transmission. Considering the conditions of non-circular gear transmission and its matching principle with crank load, a design criterion for the non-circular gear pitch curve is established. The optimal non-circular gear pitch curve is selected through simulation iteration, offering the following advantages: 1) Based on the variable crank speed motion of non-circular gears, the peak torque of the pumping unit input shaft can be significantly reduced, achieving energy saving. Taking the CYJY10-4.2-53HB model beam pumping unit as an example, energy consumption is reduced by 4.5% with a 37kW motor of the same power, and by 10.7% with a smaller 30kW motor, demonstrating significant energy-saving effects.

[0025] 2) By using non-circular gear transmission, the load fluctuations and peak values ​​of gear transmission, belt transmission and motor are reduced, fatigue damage is reduced, and the life of the first-stage gear, belt transmission and motor is extended.

[0026] This invention replaces the traditional cylindrical gear reducer with a non-circular gear transmission reducer. While maintaining the main structure of the beam pumping unit, it optimizes the design by leveraging the variable transmission ratio characteristic of non-circular gears to adapt to the load, reducing peak load at the motor and improving load fluctuations, thus achieving energy savings. This design employs a purely mechanical energy-saving method, offering advantages such as high reliability and durability. Attached Figure Description

[0027] The present invention can be better understood by referring to the description given below in conjunction with the accompanying drawings, in which the same or similar reference numerals are used throughout the drawings to denote the same or similar parts. These drawings, together with the following detailed description, are incorporated in and form part of this specification, and are used to further illustrate preferred embodiments of the invention and explain the principles and advantages of the invention. In the drawings: Figure 1 This is a simplified diagram of the motion of the novel walking beam pumping unit in this invention; Figure 2 This is a flowchart illustrating the section curve design in this invention; Figure 3This is the curve showing the change of the suspension point load over time in this invention; Figure 4 This refers to the crank load corresponding to the original structure in this invention; Figure 5 This is the crank angular velocity curve initially designed based on crank load in this invention; Figure 6 shows the crank load, motor load and corresponding current energy consumption in this invention. Figure 6(a) is a schematic diagram of the crank load, Figure 6(b) is a schematic diagram of the motor load, and Figure 6(c) is a schematic diagram of the motor current energy consumption. Figure 7 This refers to the crank angular velocity corresponding to the lowest motor energy consumption in this invention; Figure 8 shows a comparison between the non-circular structure and the original structure in this invention. Figure 8(a) is a comparison of the motor torque curves, and Figure 8(b) is a comparison of the current curves of motors with different power ratings. Figure 9 This is the non-circular gear pitch curve corresponding to the lowest energy consumption in this invention; Figure 10 This is the curvature diagram of the active wheel segment curve in this invention; Figure 11 shows the generation of the non-circular gear tooth profile in this invention. Figure 11(a) is the tooth profile of the driving gear, and Figure 11(b) is the tooth profile of the driven gear. Figure 12 shows the simulation meshing analysis of non-circular gears in this invention. Figure 12(a) shows the simulation meshing process of non-circular gears, and Figure 12(b) shows the meshing simulation curve. Detailed Implementation

[0028] Embodiments of the present invention will now be described with reference to the accompanying drawings. Elements and features described in one drawing or embodiment of the invention may be combined with elements and features shown in one or more other drawings or embodiments. It should be noted that, for clarity, representations and descriptions of components and processes unrelated to the present invention and known to those skilled in the art have been omitted from the drawings and description.

[0029] In the description of this invention, it should be understood that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] To address the energy-saving challenges of beam pumping units, this invention proposes an energy-saving design method based on non-circular gear transmission. Considering the conditions of non-circular gear transmission and its matching principle with crank load, a design criterion for the non-circular gear pitch curve is established. The optimal non-circular gear pitch curve is selected through simulation iteration, and the feasibility of the method is verified by relevant experiments. The results show that for the CYJY10-4.2-53HB model beam pumping unit, energy consumption is reduced by 4.7% with the same power motor and by 11% with a smaller power motor, demonstrating significant energy-saving effects.

[0031] 1. Energy-saving mechanism of oil pumping unit based on non-circular gear transmission A beam pumping unit consists of four parts: a walking beam, a connecting rod, a crank mechanism, a gearbox, a power unit, and auxiliary equipment. During operation, the high-speed rotation of the electric motor is reduced to a low-speed rotation of the crank via belt drive and a reducer. This low-speed rotation of the crank is then converted into the up-and-down movement of the walking beam by the crank-connecting rod mechanism. The walking beam, through the polished rod and sucker rod, drives the plunger of the downhole pump to reciprocate up and down, thereby continuously pumping crude oil from the wellbore.

[0032] Based on the working principle of a beam pumping unit, the motor load mainly depends on the crank load and the transmission structure. Due to the fluctuation of the suspension point load and the characteristics of the four-bar linkage, the crank load fluctuates significantly. Traditional reducer designs use cylindrical gear transmissions. Because the transmission ratio is fixed, the motor output cannot adapt to the crank load, causing the motor power to be selected based on the peak load, resulting in unnecessary energy consumption.

[0033] Non-circular gear transmissions have the characteristic of variable transmission ratio. By designing the transmission ratio, while ensuring that the average crank speed remains constant, compared with the original structure, they have the following advantages: 1) By changing the transmission ratio, they can adapt to the crank load, thereby reducing the peak load and fluctuation amplitude at the motor and achieving energy saving and consumption reduction; 2) When the crank load is large, while keeping the average transmission ratio the same, the non-circular gear transmission ratio can be designed to be larger than the original structure, that is, the radius of the driven gear pitch curve becomes larger, the force on the gear teeth is reduced, and the gear life is enhanced.

[0034] Therefore, based on the principle of non-circular gear transmission, the project proposed a non-circular gear reducer design for a beam pumping unit. The first stage uses a planetary gear train with a fixed large transmission ratio, while the second stage uses a non-circular gear transmission with a variable transmission ratio. By designing the pitch curve of the second-stage non-circular gear, the matching degree between the transmission ratio and the crank load is increased, improving the load fluctuation amplitude and peak value, thereby achieving energy saving. The design scheme is shown below. Figure 1 As shown: 2. Energy-saving design of non-circular gear transmission The design principle of the non-circular gear pitch curve is to fit the crank load curve by adjusting the transmission ratio curve. Theoretically, the change in the transmission ratio curve can perfectly match the crank load curve, but due to constraints such as gear strength and manufacturing process, the transmission ratio must be designed within a certain range.

[0035] This invention proposes an iterative design method based on ADAMS dynamic simulation. This method achieves a high degree of matching between the transmission ratio curve and the crank load curve, reducing the energy consumption of the pumping unit. The CYJY10-4.2-53HB model is used as an example for analysis; the specific design process is described above. Figure 2 The specific details include: Step 1: Fit the suspension load data to the initial crank angular velocity equation using Fourier series, import the initial crank angular velocity equation into the walking beam pumping unit model, obtain the first crank load through the original structure simulation, and obtain the first crank angular velocity equation based on the first crank load. Step 2: Import the first crank angular velocity equation into the walking beam pumping unit model, obtain the second crank load through simulation, calculate the motor load based on the second crank load, calculate the motor energy consumption based on the motor load, and determine whether the preset energy saving rate is met based on the motor energy consumption. If it is met, the first crank angular velocity equation is used as the final crank angular velocity equation, and proceed to step 4. The motor load is calculated by directly dividing the crank load by the total transmission ratio of the belt drive and gear drive. Since the transmission ratio is variable after using non-circular gears, the motor load is obtained by dividing the discrete points of the crank load by the discrete points of the variable transmission ratio. In addition, the motor energy consumption is calculated based on the motor load by a quantitative equation fitted by the motor torque data and the corresponding current energy consumption data. The equation expression is: current I = 0.00007314*M^2 + 0.02149*M + 17.37 (I is the motor current, and M is the motor torque).

[0036] Furthermore, whether the preset energy-saving rate is met, i.e., energy-saving verification, is achieved by comparing the existing structure with the original structure. Therefore, the same number of discrete points can be used for comparison. The preset energy-saving rate is the expected energy-saving rate. Meeting the preset energy-saving rate means selecting the curve with the highest energy-saving rate among the curves that meet the energy-saving rate requirements, which is the final curve that needs to be designed.

[0037] Step 3: If the condition is not met, adjust the first crank angular velocity equation and return to Step 2. Import the adjusted first crank angular velocity equation into the beam pumping unit model until the preset energy saving rate is achieved. The corresponding adjusted first crank angular velocity equation is then used as the final crank angular velocity equation. Specifically, adjusting the first crank angular velocity equation involves adjusting the phase angle, the upper and lower limits of the crank angular velocity fluctuation, and the order of the trigonometric function in the crank angular velocity equation. This step is used to select a balance between stability and energy saving rate. Step 4: Obtain the non-circular gear pitch curve based on the final crank angular velocity equation. That is, substitute the final crank angular velocity equation corresponding to the lowest energy consumption into the non-circular gear pitch curve and angular velocity equation to obtain the non-circular gear driving gear pitch curve.

[0038] The crank angular velocity is the transmission of the driven wheel in a non-circular gear transmission. The driving wheel rotates at a constant speed with an angular velocity of (36*π / 180) rad / s.

[0039] After numerous experiments and calculations, the formula for the crank angular velocity with respect to time t is obtained as follows: w(t) = -((1379*cos((π*t) / 5)) / 10000 - π / 5 - (9629*cos((2*π*t) / 5)) / 100000 - (4501*cos((3*π*t) / 5)) / 100000 - (7109*sin((π*t) / 5)) / 100000 + (3997*sin((2*π*t) / 5)) / 50000 + (1323*sin((3*π*t) / 5)) / 100000) After numerous experiments and calculations, the formula for crank angular velocity with respect to angle e was obtained: π / 5+(9629*cos(2*e)) / 100000+(4501*cos(3*e)) / 100000-(3997*sin(2*e)) / 50 000-(1323*sin(3*e)) / 100000-(1379*cos(e)) / 10000+(7109*sin(e)) / 100000.

[0040] Substituting the crank angular velocity into equation r1 yields the non-circular gear pitch curve, which is expressed as: r1=200*ω(t) / ((36*π / 180)+ω(t)); Finally, the non-circular drive wheel pitch curve and the drive wheel angle e are: r1=(40*π+(9629*cos(2*e)) / 500+(4501*cos(3*e)) / 500-(3997*sin(2*e)) / 2 50-(1323*sin(3*e)) / 500-(1379*cos(e)) / 50+(7109*sin(e)) / 500) / ((2*π) / 5 +(9629*cos(2*e)) / 100000+(4501*cos(3*e)) / 100000-(3997*sin(2*e)) / 5000 0-(1323*sin(3*e)) / 100000-(1379*cos(e)) / 10000+(7109*sin(e)) / 100000); If the center distance is 200, then the driven wheel pitch curve is r2 = 200 - r1.

[0041] Figure 2 The design process is described in detail below: 1) Obtaining the suspension point load The suspension point load is obtained using a load sensor, and the suspension point load equation is fitted. The function of suspension point load versus time is shown in [reference needed]. Figure 3 : Depend on Figure 3 Within one cycle of the upper and lower strokes, the suspension point load fluctuates to a certain extent, with load peaks in both strokes, the maximum value being 55.61KN and the minimum value being 19.83KN, showing a significant load difference.

[0042] 2) Establish a simulation platform A 3D model of the beam pumping unit was created and imported into ADAMS, with all parts maintaining the same structure and mass as the prototype. To simulate the tangential motion and stress state between the suspension point and the furnace head, a guide rod was installed, connected to the donkey head via a gear-rack pair.

[0043] 3) Crank load extraction The crank load was obtained by combining the walking beam pumping unit structure in the simulation. Figure 4 The crank angular velocity is obtained through simulation using a cylindrical gear reducer.

[0044] Depend on Figure 4 It is known that the first peak has a maximum value of 39950 N·m, the second peak is 37660 N·m, and the trough is a minimum value of -8071 N·m. The peak values ​​and fluctuations of the crank load are relatively large. Using a cylindrical gear with a fixed transmission ratio cannot achieve a good match between the motor and the load. Therefore, a non-circular gear transmission mechanism is adopted, and the crank angular velocity is designed in conjunction with the torque characteristics of the crank load to reduce the peak values ​​and fluctuations of the motor load.

[0045] 4) Crank angular velocity fitting Considering the large peak and fluctuation of the crank load, the optimal pitch curve cannot be obtained through a single fitting. Therefore, it is necessary to combine the crank load with the crank angular velocity fitting to obtain the crank angular velocity equation. Then, the pitch curve of the drive wheel is calculated, and the crank angular velocity is substituted into the equation. Through iterative iteration, the optimal pitch curve is obtained. Figure 4 It is known that the original motor load has two peak values. In order to reduce the peak value and fluctuation amplitude of the motor load, the crank angular velocity under non-circular gear transmission is input into ADAMS to simulate the motor load. At the same time, the counterweight is adjusted to make the two peak values ​​closer together.

[0046] During the design process, the goal is to minimize the crank angular velocity and ensure the crank is decelerating at the peak of the crank load. Figure 5 As shown, when the low-speed end and deceleration end of the crank coincide with the peak crank load end, the peak motor load can be reduced. The preliminary fitted crank angular velocity is shown in [reference needed]. Figure 9 As shown in Figure 6(a), after the initial crank angular velocity equation is input into ADAMS, the crank load obtained by simulation is shown in Figure 6(a).

[0047] Since the external torque caused by the rotational inertia of the gears is very small compared to the crank torque, it can be almost ignored. Therefore, the motor load is obtained by directly dividing the crank load by the transmission ratio, as shown in Figure 6(b). Then, the motor current energy consumption is obtained according to the formula for motor current and motor torque, as shown in Figure 6(c).

[0048] The above analysis shows that, with other factors remaining constant, the motor's energy consumption depends on the crank angular velocity. By optimizing the phase angle and change curve of the crank angular velocity, and adjusting the counterweight, repeating the simulation steps above, the crank angular velocity corresponding to the lowest motor energy consumption can be obtained. (See...) Figure 7 As shown: Figure 8(a) shows a comparison of the motor energy consumption based on the optimal non-circular gear pitch curve with the energy consumption of the original structure. As shown in Figure 8(a), the peak motor load decreased from 317.3 N·m to 238.3 N·m, a reduction of 24.9%, meeting the condition for replacing the 37 kW motor with a 30 kW motor. Under the optimal crank angular velocity, equation fitting was performed on the three curves in Figure 8(b), yielding the following results: the energy consumption of the 37 kW original structure motor is 52493 J; the energy consumption of the 37 kW non-circular structure motor is 50044 J; and the energy consumption of the 30 kW non-circular motor is 46722 J. At the same power level, the energy saving rate of the 37 kW motor is 4.7%, while the energy saving rate is 11% after selecting the 30 kW motor. The above analysis shows that the energy-saving effect of the beam pumping unit is significant after adopting non-circular gear transmission.

[0049] 4 tests Section 4.1 Curve Generation Substituting the crank angular velocity equation ω(t) corresponding to the lowest energy consumption into the non-circular gear pitch curve and angular velocity equation yields the driving gear pitch curve. The driving and driven gear pitch curves are shown below. Figure 9 As shown: Depend on Figure 10 The curvature of the gear pitch curve changes little and is of a reasonable value. Therefore, the gear will not generate significant impact or acceleration during meshing, and the pitch curve design is feasible.

[0050] 4.2 Tooth profile generation and meshing simulation Using MATLAB for non-circular gear tooth profile machining programming, the cutting tool parameters, module, addendum, and root coefficient are set. The pitch curve equation of the driving gear is input into the MATLAB program to generate the tooth profiles of the driving and driven gears, as shown in Figure 11. The established three-dimensional model is shown in Figure 12(a). First, the crank load is input to the driven wheel, and then the relevant meshing simulation curves are obtained through further gear meshing simulation analysis. As shown in Figure 12(b), the load peak and load fluctuation are reduced through gear meshing. Furthermore, the gear is subjected to uniform force and has less impact during meshing, resulting in smooth transmission.

[0051] 4.3 Experimental Verification 1) Manufacturing of non-circular gears Based on the generated tooth profile data, a gear drawing is obtained, and the master and slave non-circular gears are manufactured using wire EDM (electric cutting) with a slow wire cutting method. 2) Experiment and Analysis of Experimental Results Energy-saving experiments on reducers based on crank loads were conducted to verify the correctness and feasibility of the design method for non-circular gear reducers in oil beam pumping units. The experimental results were compared and analyzed with theoretical and simulation results to explore methods for improvement and refinement.

[0052] The crank load was simulated using a planetary reducer and current control via a magnetic powder loader. The feasibility of the scheme was verified through an energy-saving comparison experiment comparing a 1:1 cylindrical gear transmission with a non-cylindrical gear transmission. In the experiment: 1) With a 37kW motor, the energy consumption of the motor was recorded for five strokes under both 1:1 cylindrical gear transmission and non-cylindrical gear transmission conditions; 2) A 30kW motor was used, and the above steps were repeated. The energy consumption table is as follows:

[0053] Analysis of experimental results: Table 2 shows that, by comparing the total energy consumption, the average energy saving rate is 4.5% under the same power of a 37KW motor; when a 30KW motor is used, the average energy saving rate is 10.7%. Since the gear reducer moves at 6r / min, the impact of dynamic meshing loss can be ignored. The experimental results are basically consistent with the theoretical results, verifying the correctness of the theoretical design method.

[0054] 5. Conclusion This invention proposes an energy-saving design method for a beam pumping unit based on non-circular gear transmission, which improves the fluctuation amplitude and peak value of motor load, thereby achieving energy savings. Research shows that: 1) Based on the variable crank speed motion of non-circular gears, the peak torque of the pumping unit input shaft can be significantly reduced, achieving energy saving. Taking the CYJY10-4.2-53HB model beam pumping unit as an example, energy consumption is reduced by 4.5% with a 37kW motor of the same power, and by 10.7% with a smaller 30kW motor, demonstrating significant energy-saving effects.

[0055] 2) By using non-circular gear transmission, the load fluctuations and peak values ​​of gear transmission, belt transmission and motor are reduced, fatigue damage is reduced, and the life of the first-stage gear, belt transmission and motor is extended.

[0056] In the above description of specific embodiments of the present invention, features described and / or shown for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0057] It should be emphasized that the term "comprising / including" as used in this invention refers to the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0058] Although the invention has been disclosed above through the description of specific embodiments, it should be understood that all the embodiments and examples described above are exemplary and not restrictive. Those skilled in the art can design various modifications, improvements, or equivalents to the invention within the spirit and scope of the appended claims. These modifications, improvements, or equivalents should also be considered to be included within the protection scope of the invention.

Claims

1. An energy-saving design method based on non-circular gear transmission, characterized in that: include: Step 1: Fit the suspension load data to the initial crank angular velocity equation using Fourier series, import the initial crank angular velocity equation into the walking beam pumping unit model, obtain the first crank load through the original structure simulation, and obtain the first crank angular velocity equation based on the first crank load. Step 2: Import the first crank angular velocity equation into the walking beam pumping unit model, obtain the second crank load through simulation, calculate the motor load based on the second crank load, calculate the motor energy consumption based on the motor load, and determine whether the preset energy saving rate is met based on the motor energy consumption. If it is met, the first crank angular velocity equation is used as the final crank angular velocity equation, and proceed to step 4. Step 3: If the condition is not met, adjust the first crank angular velocity equation and return to step 2. Import the adjusted first crank angular velocity equation into the walking beam pumping unit model until the preset energy saving rate is met. The corresponding adjusted first crank angular velocity equation is then used as the final crank angular velocity equation. Step 4: Obtain the non-circular gear pitch curve based on the final crank angular velocity equation.

2. The energy-saving design method based on non-circular gear transmission according to claim 1, characterized in that: In step 1, the suspension point load data is obtained by using a load sensor to obtain the suspension point load, and then fitting the suspension point load equation through the suspension point load.

3. The energy-saving design method based on non-circular gear transmission according to claim 1, characterized in that: In step 1, the walking beam pumping unit model is established by importing the three-dimensional model of the walking beam pumping unit into ADAMS.

4. The energy-saving design method based on non-circular gear transmission according to claim 1, characterized in that: In step 1, the first crank load is obtained by simulating the walking beam pumping unit model and combining it with the structure of the walking beam pumping unit.

5. The energy-saving design method based on non-circular gear transmission according to claim 1, characterized in that: The equation for crank angular velocity with respect to time t is expressed as follows: ω(t)=-((1379*cos((π*t) / 5)) / 10000-π / 5- (9629*cos((2*π*t) / 5)) / 100000-(4501*cos((3*π*t) / 5)) / 100000-(7109*sin((π* t) / 5)) / 100000+(3997*sin((2*π*t) / 5)) / 50000+(1323*sin((3*π*t) / 5)) / 100000); The formula for crank angular velocity with respect to angle e is as follows: ω(e)=π / 5+(9629*cos(2*e)) / 100000+(4501*cos(3*e)) / 100000- (3997*sin(2*e)) / 50000-(1323*sin(3*e)) / 100000-(1379*cos(e)) / 10000+(7109*sin(e)) / 100000; The non-circular gear pitch curve is obtained based on the final crank angular velocity equation. Specifically, the final crank angular velocity equation is substituted into equation r1 to obtain the non-circular gear pitch curve. Equation r1 is expressed as follows: r1=(40*π+(9629*cos(2*e)) / 500+(4501*cos(3*e)) / 500-(3997*sin(2*e)) / 2 50-(1323*sin(3*e)) / 500-(1379*cos(e)) / 50+(7109*sin(e)) / 500) / ((2*π) / 5 +(9629*cos(2*e)) / 100000+(4501*cos(3*e)) / 100000-(3997*sin(2*e)) / 5000 0-(1323*sin(3*e)) / 100000-(1379*cos(e)) / 10000+(7109*sin(e)) / 100000).

6. A walking beam pumping unit based on non-circular gear transmission, characterized in that: The unit comprises a walking beam, a connecting rod, a crank, a non-circular gear pair, and a planetary gear train connected in sequence. This walking beam pumping unit employs a non-circular gear transmission reducer, with the planetary gear train serving as the first stage of transmission. The planetary gear train utilizes a fixed high transmission ratio. The non-circular gear pair serves as the second stage of transmission, and the matching degree between the transmission ratio and the crank load is increased by designing the non-circular gear pitch curve of the second stage. The non-circular gear pitch curve is implemented using the energy-saving design method based on non-circular gear transmission as described in any one of claims 1-5.

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