Heat balance regulation and control method for energy-saving and efficiency-improving high-precision worm grinding wheel gear grinding machine

Abstract

The invention provides a heat balance regulation and control method for a high-precision worm grinding wheel gear grinding machine for energy conservation and efficiency improvement. The method comprises the steps of establishing an electric-mechanical-thermal energy balance matrix equation of the worm grinding wheel gear grinding machine, carrying out a gear grinding experiment and carrying out data acquisition and processing, establishing a thermal energy balance equation, establishing a comprehensive energy efficiency model, establishing a comprehensive optimization model, solving the optimization model and the like. The heat balance regulation and control strategy of the worm grinding wheel gear grinding machine is obtained through the method, and a guidance basis is provided for energy conservation and efficiency improvement of the gear grinding machine. And a theoretical model and a guidance basis are provided for heat balance regulation and control of the energy-saving worm grinding wheel gear grinding machine. The device is high in universality and wide in applicability, and can be subsequently popularized and applied to other gear manufacturing machine tools.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mechanical manufacturing, in particular to a high-precision worm grinding machine heat balance regulation method for energy saving and efficiency improvement. BACKGROUND

[0002] Gear is a basic component of mechanical transmission, and its machining precision and reliability directly determine the performance and service life of key equipment such as automobiles, wind power, aerospace, etc. Gear manufacturing machine tool, as the key carrier of gear manufacturing process, directly determines the machining precision and efficiency.

[0003] Worm grinding machine is a typical gear machining equipment, widely used in gear manufacturing field, its principle is to use worm-shaped grinding wheel and gear workpiece meshing continuous generation for grinding, similar to gear hobbing process. In the process of gear grinding, due to the small contact area of worm grinding wheel and gear workpiece, the local pressure is large, the grinding heat is concentrated, which is easy to cause gear burn problem; in addition, due to large grinding power, the heat of the main shaft and other moving shafts is obvious, which makes the internal environment of high-precision worm grinding machine in thermal instability state, which is easy to cause thermal deformation of machine tool structure, and then affects the machining quality. Therefore, in order to maintain the thermal stability of the internal environment of the grinding machine and ensure the machining precision of the grinding machine, a large amount of electric energy needs to be input for driving the heat balance regulation process, such as cooling, lubrication, constant temperature control, etc. This not only increases the electric energy consumption, but also reduces the energy utilization rate of the grinding machine.

[0004] The research on the heat balance regulation method of high-precision worm grinding machine for energy saving and efficiency improvement can reveal the comprehensive influence of worm grinding process parameters and heat balance regulation process control parameters on energy consumption, energy efficiency and heat balance state of worm grinding process, realize the accurate and scientific evaluation of energy use and heat balance regulation effect of worm grinding process, and lay a theoretical foundation for the optimization of worm grinding process parameters and the optimization design of heat balance regulation equipment. However, the existing technology cannot comprehensively reveal the comprehensive influence of multi-parameters on energy utilization and heat balance regulation effect from the aspects of energy saving and heat balance regulation.

[0005] Therefore, it is of great significance to develop a high-precision worm grinding machine heat balance regulation method for energy saving and efficiency improvement to realize green precision machining of worm grinding process. SUMMARY

[0006] The purpose of the present application is to provide a high-precision worm grinding machine heat balance regulation method for energy saving and efficiency improvement to solve the problems in the prior art.

[0007] The technical solution adopted to achieve the purpose of the present application is as follows: a high-precision worm grinding machine heat balance regulation method for energy saving and efficiency improvement, comprising the following steps:

[0008] 1) Define the energy boundary of high-precision worm grinding machine system, analyze the energy transfer and conversion law of worm grinding machine. Combined with energy flow matrix method, the worm grinding machine electrical-mechanical-thermal energy balance matrix equation is established as shown in equation (1) and equation (2).

[0009] (1)

[0010] (2)

[0011] In the formula, is the input-node associated matrix, is the output-node associated matrix, is the input matrix, is the output matrix, is the input efficiency matrix, is the electrical energy matrix, is the input mechanical energy matrix, is the output mechanical energy matrix, is the thermal energy matrix.

[0012] 2) Develop grinding experiments and data collection and processing.

[0013] 3) Comprehensive consideration of the thermal energy characteristics of different functional modules of worm grinding machine, establish the thermal energy balance equation. Define the thermal energy weight, establish the worm grinding machine thermal energy accumulation model with weight as shown in equation (3). Wherein, the worm grinding machine thermal energy related area is divided into cutting space (4) and material removal unit. The material removal unit includes spindle (1), feed shaft (2) and rotary table (3).

[0014] (3)

[0015] In the formula, is the thermal accumulation amount. Weight . is the heat value. represents a function related to cutting parameters, represents a function related to the state parameters of thermal balance control medium.

[0016] 4) From the perspective of energy utilization, establish the energy consumption model and comprehensive energy efficiency model of worm grinding machine material removal process and thermal balance control process. Among them, according to the type of energy-consuming unit, the energy source of worm grinding machine is divided into material removal related energy consumption , thermal balance control related energy consumption and basic auxiliary function related energy consumption . The total energy consumption of worm grinding machine is represented by the following formula:

[0017] (4)

[0018] Where, the total energy consumption of the material removal unit is a function of the cutting parameters and the unit running time, i.e.:

[0019] (5)

[0020] The total energy consumption of the thermal balance regulation unit is a function of the refrigeration coefficient COP, mass flow, temperature variables and time, i.e.:

[0021] (6)

[0022] The total energy consumption of the auxiliary unit is related to the unit rated power and running time, and the expression is as follows:

[0023] (7)

[0024] Gear grinding machine cutting efficiency The definition is as follows:

[0025] (8)

[0026] In the formula, Mechanical energy required for cutting, Total energy consumption of the worm grinding machine.

[0027] The mechanical energy is calculated as follows:

[0028] (9)

[0029] 5) Build a comprehensive optimization model of the worm grinding machine cutting parameters and thermal balance regulation control parameters considering energy saving, efficiency improvement and thermal stability.

[0030] (10)

[0031] The optimization model strategy is to comprehensively consider the influence of cutting parameters, thermal balance regulation parameters, environmental parameters, etc. on the characteristics of the electric-mechanical-thermal coupling, and find a set of optimal parameter set to make 、 、 reach balance.

[0032] 6) Solve the optimization model to get the worm grinding machine thermal balance regulation strategy.

[0033] Further, in step 2), PT100 thermocouples are used to collect reference point temperatures. NI-9214 data acquisition cards are used to collect temperature data. FLUKE Ti32 thermal imagers are used to assist in collecting temperature data.

[0034] Further, the thermocouple arrangement positions include external environment, worm gear grinding machine body, worm gear grinding wheel spindle front end cover, worm gear grinding wheel spindle side, worm gear grinding wheel spindle motor end cover, worm gear grinding wheel spindle rear end cover, X feed shaft end, Y feed shaft end, Z feed shaft end, workpiece spindle side, gear grinding machine internal space, small column, lubricating oil inlet pipe, lubricating oil outlet pipe, hydraulic oil inlet pipe, hydraulic oil outlet pipe, cooling liquid inlet, cooling liquid outlet and compressed air.

[0035] Further, in step 2), current / voltage information is collected by using current / voltage sensors, and the collection method is three-phase three-wire measurement method, and HIOKI 3390 type power analyzer is used to collect power information.

[0036] Further, in step 3), the weights of each heat are determined by expert scoring method.

[0037] Further, in step 6), NSGA-II algorithm is used to solve the optimization problem shown in formula (10) by combining Euclidean technique and TOPSIS decision method.

[0038] Further, step 6) specifically includes the following sub-steps:

[0039] 6.1) Initialize the population, and randomly generate a population. The population size is N.

[0040] 6.2) Perform fast non-dominated sorting and crowding degree calculation.

[0041] 6.3) Obtain the first generation of offspring population by means of selection, crossover and mutation operations.

[0042] 6.4) Merge the parent and child populations.

[0043] 6.5) Perform fast non-dominated sorting and crowding degree calculation.

[0044] 6.6) Select appropriate individuals based on non-dominated relationship and crowding degree to generate a new population.

[0045] 6.7) Repeat the above operations to obtain all Pareto optimal solutions that meet the requirements.

[0046] 6.8) Obtain dimensionless target by using Euclidean technique.

[0047] 6.9) Sort the optimal solution by using TOPSIS decision method, and select the solution closest to the ideal solution.

[0048] The technical effect of the present application is self-evident: improving the thermal environment of the internal space of the worm grinding machine, providing guidance for energy saving and efficiency improvement of the grinding machine. The present application provides a theoretical model and guidance for the thermal balance regulation of the energy-saving worm grinding machine. The present application has strong universality and wide applicability, and can be applied to other gear manufacturing machines in the future. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 is a method flowchart;

[0050] Figure 2 is a schematic diagram of a high-precision worm grinding machine;

[0051] Figure 3 is a schematic diagram of the energy-mechanical-thermal energy coupling of a high-precision worm grinding machine;

[0052] Figure 4 is an optimization solution flowchart based on the NSGA-II algorithm.

[0053] In the figure: main shaft 1, feed shaft 2, rotary table 3, cutting space 4, hydraulic oil station 5, air conditioner 6, compressed air station 7, lubricating oil station 8, air filter 9, cooling station 10, electric control cabinet 11. DETAILED DESCRIPTION

[0054] The present application will be further described below in conjunction with examples, but should not be understood as limiting the above-mentioned subject matter of the present application to the following examples. Various substitutions and modifications can be made according to ordinary technical knowledge and conventional means in the art without departing from the above-mentioned technical idea of the present application, and all such substitutions and modifications shall be included in the protection scope of the present application.

[0055] Example 1

[0056] Referring to Figure 1 , the present embodiment provides a high-precision worm grinding machine thermal balance regulation method for energy saving and efficiency improvement, comprising the following steps:

[0057] 1) Define the energy boundary of the high-precision worm grinding machine system, refer to Figure 2 , analyze the energy transfer and conversion law of the worm grinding machine. Combined with the energy flow matrix method, the worm grinding machine electrical-mechanical-thermal energy balance matrix equation is established as shown in equation (1) and equation (2).

[0058] (1)

[0059] (2)

[0060] In the formula, is the input-node association matrix, is the output-node association matrix, is the input matrix, is the output matrix, is the input efficiency matrix, is the electrical energy matrix, is the input mechanical energy matrix, is the output mechanical energy matrix, is the thermal energy matrix.

[0061] 2) Conduct gear grinding experiments and collect and process data.

[0062] 3) Considering the thermal energy characteristics of different functional modules of the high-precision worm grinding machine, establish a thermal energy balance equation. Define the thermal energy weight and establish a weighted thermal energy accumulation model of the high-precision worm grinding machine as shown in equation (3). Among them, the thermal energy related area of the high-precision worm grinding machine is divided into a cutting space (4) and a material removal unit. The material removal unit includes a spindle (1), a feed shaft (2), and a rotary table (3).

[0063] (3)

[0064] In the formula, is the thermal accumulation amount. Weight . is the heat value. represents a function related to the cutting parameters, represents a function related to the state parameters of the thermal balance control medium.

[0065] 4) From the perspective of energy utilization, establish the material removal process, thermal balance control process energy consumption model and comprehensive energy efficiency model of the worm grinding machine. Among them, according to the type of energy-consuming unit, the energy source of the worm grinding machine is divided into material removal related energy consumption , thermal balance control related energy consumption and basic auxiliary function related energy consumption . The total energy consumption of the worm grinding machine is represented by the following formula:

[0066] (4)

[0067] Among them, the total energy consumption of the material removal unit is a function of the cutting parameters and the unit running time, that is:

[0068] (5)

[0069] The total energy consumption of the thermal balance control unit is a function of the refrigeration coefficient COP, mass flow, temperature variable and time, that is:

[0070] (6)

[0071] The total energy consumption of the base auxiliary unit is related to the unit rated power and the operation time, and the expression is as follows:

[0072] (7)

[0073] Gear grinding machine cutting efficiency The definitions are as follows:

[0074] (8)

[0075] In the formula, represents the mechanical energy required for cutting, represents the total energy consumption of the worm grinding machine.

[0076] The mechanical energy is calculated as follows:

[0077] (9)

[0078] 5) Construct a comprehensive optimization model of the worm grinding machine cutting parameters and thermal balance control parameters considering energy saving, efficiency improvement and thermal stability.

[0079] (10)

[0080] The optimization model strategy is to comprehensively consider the influence of cutting parameters, thermal balance control parameters and environmental parameters on the electrical-mechanical-thermal coupling characteristics, and find a set of optimal parameter set to make 、 、 reach balance.

[0081] 6) Solve the optimization model to obtain the thermal balance control strategy of the worm grinding machine.

[0082] Example 2:

[0083] The main content of this example is the same as that of example 1, wherein in step 2), a PT100 type thermocouple is used to collect the reference point temperature. A NI-9214 type acquisition card is used to collect temperature data. A FLUKE Ti32 type thermal imager is used to assist in collecting temperature data. The thermocouple is arranged at positions including the external environment, the worm grinding machine bed, the front end cover of the worm grinding machine spindle, the side of the worm grinding machine spindle, the motor end cover of the worm grinding machine spindle, the rear end cover of the worm grinding machine spindle, the end of the X feed shaft, the end of the Y feed shaft, the end of the Z feed shaft, the side of the workpiece spindle, the internal space of the gear grinding machine, the small column, the lubricating oil inlet pipe, the lubricating oil outlet pipe, the hydraulic oil inlet pipe, the hydraulic oil outlet pipe, the cooling liquid inlet, the cooling liquid outlet and compressed air. A current / voltage sensor is used to collect current / voltage information, and a three-phase three-wire measurement method is used. A HIOKI 3390 type power analyzer is used to collect power information.

[0084] Example 3:

[0085] The main content of this embodiment is the same as that of Embodiment 1 or 2, wherein in step 3), the weight of each heat is determined by expert scoring method.

[0086] Embodiment 4:

[0087] The main content of this embodiment is the same as that of any one of Embodiments 1 to 3, wherein referring to Figure 4 , in step 6), the optimization problem shown in equation (10) is solved by using NSGA-II algorithm combined with Euclidean technique and TOPSIS decision method. Step 6) specifically includes the following sub-steps:

[0088] 6.1) Initialize the population, and randomly generate a population. The population size is N.

[0089] 6.2) Perform fast non-dominated sorting and crowding distance calculation.

[0090] 6.3) Obtain the first generation of offspring population by means of selection, crossover and mutation operations.

[0091] 6.4) Merge the parent and child populations.

[0092] 6.5) Perform fast non-dominated sorting and crowding distance calculation.

[0093] 6.6) Select appropriate individuals based on non-dominated relationship and crowding degree to generate a new population.

[0094] 6.7) Repeat the above operations to obtain all Pareto optimal solutions that meet the requirements.

[0095] 6.8) Obtain dimensionless objectives by using Euclidean technique.

[0096] 6.9) Sort the optimal solutions by using TOPSIS decision method, and select the solution closest to the ideal solution.

[0097] Embodiment 5:

[0098] The worm gear grinding machine has many functional units, and the running time, working parameters and running state of each unit are different, and the external environment changes all the time. As shown in Figure 2 , there are a series of multi-energy conversion processes such as electrical energy-mechanical energy conversion, mechanical energy-thermal energy conversion, electrical energy-thermal energy conversion and heat exchange in the high-precision worm gear grinding machine. After multi-energy conversion, heat is continuously generated, dissipated and accumulated inside the machine tool, causing internal thermal instability of the grinding machine.

[0099] The embodiment provides a high-precision worm gear grinding machine thermal balance regulation and control method for energy saving and efficiency improvement, comprising the following steps:

[0100] 1) Define the energy boundary of high-precision worm grinding machine system, see Figure 2 , analyze the energy transfer and conversion law of high-precision worm grinding machine. Combined with the energy flow matrix method, the high-precision worm grinding machine electrical-mechanical-thermal energy balance matrix equation is established as shown in equation (1) and equation (2).

[0101] (1)

[0102]

[0103] In the formula, is the input-node associated matrix, is the output-node associated matrix, is the input matrix, is the output matrix, is the input efficiency matrix, is the electrical energy matrix, is the input mechanical energy matrix, is the output mechanical energy matrix, is the thermal energy matrix.

[0104] The related symbols, expressions and explanations in the above formula are shown in Table 1.

[0105] Table 1

[0106]

[0107] As can be seen from equation (2), different forms of energy of worm grinding machine are related to each other, and finally affect the accumulation of internal thermal energy of the grinding machine. Research shows that the machining precision is closely related to the error of the grinding machine, and about 70% or even more errors are caused by thermal errors. This means that the grinding machine needs a stable internal thermal environment to reduce the influence of thermal effects on machining precision. Therefore, a large amount of electrical energy is used for heat balance regulation and control process of the machine tool, such as cooling and lubrication. About 60% of the electrical energy is used for the heat balance regulation and control process of the worm grinding machine, which is much more than the mechanical energy consumption for material removal. From the perspective of heat transfer, the more electrical energy input into the heat balance regulation and control process, the more heat taken away from the internal structure of the grinding machine, the better the heat balance state, and the higher the machining precision. But this is at the expense of machining efficiency and energy consumption, which is not consistent with the actual efficient and energy-saving production philosophy. Therefore, a heat balance regulation and control method for high-precision worm grinding machine is needed, which can realize the trade-off of energy consumption, efficiency and thermal energy accumulation of high-precision worm grinding machine.

[0108] 2) Develop grinding experiments and collect and process data.

[0109] 3) The thermal energy characteristics of different functional modules of the high-precision worm grinding machine are comprehensively considered to establish a thermal energy balance equation. A thermal energy weight is defined, and a weighted thermal energy accumulation model of the high-precision worm grinding machine is established. Due to the different heat generation and dissipation modes of different thermal energy-related regions of the high-precision worm grinding machine, the thermal energy accumulation characteristics also differ. The thermal energy-related regions of the worm grinding machine are divided into a cutting space 4 and a material removal unit. The material removal unit includes a spindle 1, a feed shaft 2, and a rotary table 3.

[0110] The following describes a typical material removal unit, the spindle, driven by electrical energy. The spindle rotates to generate the mechanical energy required for grinding. The motor rotor, stator, and bearings generate heat during rotation due to factors such as friction and power loss. To maintain the stability of the internal thermal environment of the spindle system, it is necessary to continuously supply cooling liquid, compressed air, lubricating oil, and other thermal control media to the spindle. At the same time, the system exchanges heat with the external environment, dissipating some of the heat. According to the energy flow matrix modeling method, the spindle system energy balance matrix equation is established as follows:

[0111]

[0112]

[0113]

[0114] (6)

[0115] (7)

[0116] The spindle system thermal accumulation formula is derived as follows:

[0117] (8)

[0118] The thermal accumulation models of the X, Y, Z feed shafts, and rotary table of the worm grinding machine are similar to those of the spindle system, and are not described here.

[0119] The cutting space is the place where material removal is completed, and it is also the place where the most intense thermal activity occurs inside the worm grinding machine. The cutting space includes: worm grinding wheel, gear workpiece, chip, air filter, compressed air station, cutting fluid station, automatic feeding and discharging, chip remover, and other structures, units, by-products related to the thermal equilibrium state of the cutting space. Since the worm grinding wheel is always in the cutting space, the heat it carries will be transferred to the air in the cutting space, and the transferred heat will become part of the accumulated heat in the cutting space. Therefore, the main heat source of the cutting space is the cutting heat, and the heat dissipation of the cutting space is related to the heat dissipation of the cutting fluid, the discharge of the chip, the removal of the gear workpiece, the inflow and outflow of the air, and the heat exchange between the machine tool and the cutting space.

[0120] Energy flow analysis of the cutting space:

[0121] (9)

[0122] (10)

[0123] (11)

[0124] (12)

[0125] (13)

[0126] The worm grinding machine cutting space heat accumulation formula is derived:

[0127] (14)

[0128] Further derivation of equation (8) and equation (14) gives:

[0129] (15)

[0130] In the formula, represents a function related to the cutting parameters, represents a function related to the state parameters of the thermal equilibrium control medium.

[0131] Since the magnitude of heat accumulation in each area and unit of the worm wheel gear grinder is different, their contributions to the overall thermal balance state of the gear grinder system are different. Therefore, when analyzing the thermal balance characteristics of the gear grinder and improving and optimizing the thermal balance state, if all the heat accumulations are simply added together and then the total heat accumulation is optimized, it is very easy for one area to be over-optimized (a large amount of heat balance control medium is transported to that area, causing unnecessary waste) and one area to not be optimized (a small amount of control medium is transported to that area, causing the thermal environment there to continue to be poor, affecting the thermal stability of the structure / unit), which is contrary to the overall thermal balance control concept of the gear grinder. Therefore, it is considered to normalize each heat accumulation so that the heat value range is between 0-1 ( , ,…, ,… ), then the weights of each heat accumulation were determined using the expert scoring method. Finally, a weighted heat accumulation model for a worm wheel gear grinder was established. Table 2 shows the weights of each heat accumulation determined using the expert scoring method.

[0132] Table 2 Expert scoring method to determine the weight of each heat accumulation amount (the levels in the table are for reference only, not exact levels)

[0133]

[0134] Note:

[0135] According to the weights of each heat accumulation amount obtained by the expert scoring method, the weighted heat accumulation model of the worm wheel gear grinding machine is constructed as follows:

[0136] (16)

[0137] The above formula shows that the total heat accumulation of the worm wheel gear grinding machine is the product of the multi-energy coupling of electrical energy, mechanical energy and thermal energy. The overall thermal balance state of the gear grinding machine is jointly affected by cutting parameters, thermal balance control parameters, etc.

[0138] 4) From the perspective of energy utilization, the energy consumption model of the material removal process and the heat balance control process of the worm wheel gear grinder and the comprehensive energy efficiency model are established. Among them, the energy source of the worm wheel gear grinder is divided into energy consumption related to material removal and energy consumption related to heat balance control according to the type of energy consumption unit. , energy consumption related to heat balance regulation and energy consumption associated with basic auxiliary functions The total energy consumption of the worm wheel gear grinding machine is expressed by the following formula:

[0139] (17)

[0140] Among them, the total energy consumption of the material removal unit is a function of cutting parameters and unit running time, that is:

[0141] (18)

[0142] The total energy consumption of the thermal balance regulation unit is a function of the refrigeration coefficient (COP), mass flow, temperature variable and time, i.e.:

[0143] (19)

[0144] In particular, the energy consumption of the chip remover and the automatic loading and unloading device is a function of the chip and gear temperature

[0145] The total energy consumption of the auxiliary unit is related to the rated power and operation time of the unit, and the expression is as follows:

[0146] (20)

[0147] In addition, the cutting efficiency is also an important indicator for evaluating the performance of the worm grinding machine. According to the definition of energy efficiency, the cutting efficiency of the gear grinding machine is defined as follows:

[0148] (21)

[0149] In the formula, represents the mechanical energy required for cutting, represents the total energy consumption of the worm grinding machine.

[0150] The mechanical energy is calculated as follows:

[0151] (22)

[0152] Therefore, the cutting efficiency is a function of the cutting parameters, thermal balance regulation parameters and environmental parameters.

[0153] 5) A comprehensive optimization model of the worm grinding machine cutting parameters and thermal balance regulation control parameters considering energy saving, efficiency improvement and thermal stability is constructed.

[0154] According to the above analysis, the thermal balance characteristics of the worm grinding machine are affected by the electro-mechanical-thermal multi-energy coupling effect. When trying to reduce the accumulation of heat inside the gear grinding machine, it may lead to an increase in the energy consumption of the gear grinding machine and a decrease in the cutting efficiency. Therefore, considering the electro-mechanical-thermal multi-energy coupling characteristics, the present application proposes a high-precision worm grinding machine thermal balance regulation method for energy saving and efficiency improvement to balance the overall / local thermal stability of the gear grinding machine, the total energy usage and the material removal efficiency, so that The minimum, gear grinding machine overall heat balance state is best, the energy consumption is lowest, the cutting efficiency is highest. The proposed strategy is to consider the influence of cutting parameters, heat balance control parameters, environmental parameters and other parameters on the characteristics of the electric-motor-thermal coupling, to find a set of optimal parameter set, so that 、 、 reach equilibrium. The heat balance control strategy can be represented by a multi-objective optimization problem:

[0155] (23)

[0156] 6) Solve the optimization model to obtain the worm grinding wheel grinding machine heat balance control strategy. The present application adopts NSGA-II (Non-dominated Sorting Genetic Algorithms-II) optimization algorithm combined with Euclidean technique and TOPSIS (Technique for Order Preference by Similarity to Ideal Solution, Technique for Order Preference by Similarity to Ideal Solution) decision method to solve the optimization problem shown in formula (23). NSGA-II algorithm is a kind of efficient multi-objective optimization algorithm, its core idea is to balance the convergence and diversity of solution through fast non-dominated sorting and crowding distance mechanism; Euclidean technique is used to obtain dimensionless optimization target; TOPSIS is a kind of multi-attribute decision analysis method, its core principle is to construct ideal solution (combination of optimal values of each index) and negative ideal solution (combination of worst values of each index), calculate the Euclidean distance of each alternative solution from the two, and finally sort according to the relative closeness of the scheme to the ideal solution.

[0157] The flow chart of solving the optimization problem shown in formula (23) by the above method is shown in Figure 3 . Step 6) specifically includes the following sub-steps:

[0158] 6.1) Initialize the population, randomly generate a population. The population size is N.

[0159] 6.2) Perform fast non-dominated sorting and crowding degree calculation.

[0160] 6.3) Obtain the first generation of offspring population by selection, crossover and mutation operations.

[0161] 6.4) Merge the parent and child population.

[0162] 6.5) Perform fast non-dominated sorting and crowding degree calculation.

[0163] 6.6) Select appropriate individuals based on non-dominated relationship and crowding degree to generate new population.

[0164] 6.7) Repeat the above operations to obtain all Pareto optimal solutions that meet the requirements.

[0165] 6.8) Obtain the dimensionless objective using the Euclidean technique.

[0166] 6.9) Sort the optimal solutions using the TOPSIS decision-making method and select the solution closest to the ideal solution.

[0167] Example 6:

[0168] The main content of this embodiment is the same as any one of examples 1-5, wherein this embodiment takes YS7232 high-precision worm grinding machine as the implementation object. The grinding machine is mainly used for precision grinding of cylindrical gears in new energy vehicle, aerospace, passenger car, commercial vehicle, precision reducer and other industries. The machine tool has a total of eleven standard shafts, the grinding wheel spindle adopts a high-power direct-drive electric spindle, and each linear shaft adopts a high-rigidity rolling linear guide rail. The structure of the high-precision worm grinding machine is shown in Figure 2 The grinding machine is equipped with a hydraulic oil station 5, an air conditioner 6, a compressed air station 7, a lubricating oil station 8, an air filter 9, a cooling station 10, an electric control cabinet 11 and other components.

[0169] In this implementation case, PT100 thermocouples are used to collect reference point temperatures, NI-9214 acquisition cards are used to collect temperature data, FLUKE Ti32 thermal imagers are used to assist in collecting temperature data, current / voltage sensors are used to collect current / voltage information, three-phase three-wire measurement method is used for collection, and HIOKI 3390 power analyzers are used to collect power information. The specific positions of the thermocouples arranged in this implementation case are shown in Table 3.

[0170] Table 3 Thermocouple positions

[0171] Number Position Number Position T#1 External environment T#11 Internal space of grinding machine T#2 High-precision worm grinding machine bed T#12 Small column T#3 Front end cover of worm grinding spindle T#13 Lubricating oil inlet pipe T#4 Side of worm grinding spindle T#14 Lubricating oil outlet pipe T#5 Motor end cover of worm grinding spindle T#15 Hydraulic oil inlet pipe T#6 Rear end cover of worm grinding spindle T#16 Hydraulic oil outlet pipe T#7 End of X feed shaft T#17 Cooling liquid inlet T#8 End of Y feed shaft T#18 Cooling liquid outlet T#9 End of Z feed shaft T#19 Compressed air outlet T#10 Side of workpiece spindle

Claims

1. A method for controlling thermal balance of a high-precision worm wheel gear grinding machine for energy saving and efficiency improvement, characterized in that: The following steps are involved: 1) Define the energy boundary of the high-precision worm wheel gear grinding machine system and analyze the energy transfer and conversion law of the gear grinding machine; combine the energy flow matrix method to establish the gear grinding machine electrical-mechanical-thermal energy balance matrix equations as shown in Equations (1) and (2); Where, is the input-node association matrix, is the output-node association matrix, is the input matrix, is the output matrix, is the input efficiency matrix, is the electric energy matrix, is the input mechanical energy matrix, is the output mechanical energy matrix, is the thermal energy matrix; 2) Carry out gear grinding experiments and collect and process data; 3) Comprehensively considering the thermal energy characteristics of different functional modules of the worm grinding wheel gear grinder, a thermal energy balance equation is established; defining thermal energy weights, and establishing a weighted thermal energy accumulation model of the worm grinding wheel gear grinder as shown in formula (3); wherein the thermal energy-related area of ​​the worm grinding wheel gear grinder is divided into a cutting space (4) and a material removal unit; the material removal unit includes a spindle (1), a feed axis (2) and a rotary table (3); (3) Where, is the heat accumulation; weight ; Get the value for the heat; represents the function related to cutting parameters, Represents a function related to the state parameters of the heat balance control medium; 4) From the perspective of energy utilization, the energy consumption model of the material removal process and the heat balance control process of the high-precision worm wheel gear grinding machine and the comprehensive energy efficiency model are established; among them, the energy source of the worm wheel gear grinding machine is divided into energy consumption related to material removal according to the type of energy consumption unit , energy consumption related to heat balance regulation and energy consumption associated with basic auxiliary functions The total energy consumption of the worm wheel gear grinding machine is expressed by the following formula: (4) Among them, the total energy consumption of the material removal unit is a function of the cutting parameters and the unit running time, that is: (5) The total energy consumption of the heat balance control unit is a function of the cooling coefficient COP, mass flow, temperature variation and time, namely: (6) The total energy consumption of the basic auxiliary unit is related to the unit rated power and operating time, and the expression is as follows: (7) Gear grinding machine cutting efficiency The definition is as follows: (8) Where, Indicates the mechanical energy required for cutting, Indicates the total energy consumption of the worm wheel gear grinding machine; The mechanical energy is calculated as follows: (9) 5) Construct a comprehensive optimization model for the cutting parameters and thermal balance control parameters of a worm wheel gear grinder, taking into account energy saving, efficiency improvement, and thermal stability; (10) The optimization model strategy is to comprehensively consider the effects of cutting parameters, thermal balance control parameters, environmental parameters, etc. on the electro-mechanical-thermal coupling characteristics, and find a set of optimal parameter sets. 、 、 Achieve a balance; 6) Solve the optimization model to obtain the thermal balance control strategy of the worm wheel gear grinder.

2. The method for controlling thermal balance of a worm wheel gear grinding machine for energy saving and efficiency improvement according to claim 1, characterized in that: In step 2), a PT100 thermocouple is used to collect the reference point temperature; an NI-9214 acquisition card is used to collect temperature data; and a FLUKE Ti32 thermal imager is used to assist in collecting temperature data.

3. The method for controlling the thermal balance of a worm wheel gear grinding machine for energy saving and efficiency improvement according to claim 2, characterized in that: The thermocouple layout positions include the external environment, the worm grinding wheel gear grinding machine bed, the front end cover of the worm grinding wheel spindle, the side of the worm grinding wheel spindle, the end cover of the worm grinding wheel spindle motor, the rear end cover of the worm grinding wheel spindle, the end of the X feed axis, the end of the Y feed axis, the end of the Z feed axis, the side of the workpiece spindle, the space inside the gear grinding machine, the small column, the lubricating oil inlet pipe, the lubricating oil outlet pipe, the hydraulic oil inlet pipe, the hydraulic oil outlet pipe, the coolant inlet, the coolant outlet and the compressed air.

4. The method for controlling thermal balance of a worm wheel gear grinding machine for energy saving and efficiency improvement according to claim 1, characterized in that: In step 2), a current / voltage sensor is used to collect current / voltage information, and a three-phase three-wire measurement method is used for collecting power information. A HIOKI 3390 power analyzer is used to collect power information.

5. The method for controlling thermal balance of a worm wheel gear grinding machine for energy saving and efficiency improvement according to claim 1, characterized in that: In step 3), the weight of each calorie is determined by expert scoring method.

6. The method for controlling thermal balance of a worm wheel gear grinding machine for energy saving and efficiency improvement according to claim 1, characterized in that: In step 6), the NSGA-II algorithm is combined with the Euclidean technique and the TOPSIS decision method to solve the optimization problem shown in formula (10).

7. The method for controlling thermal balance of a worm wheel gear grinding machine for energy saving and efficiency improvement according to claim 6, characterized in that: Step 6) specifically includes the following sub-steps: 6.1) Initialize the population and randomly generate a population of size N. 6.2) Perform fast non-dominated sorting and congestion calculation; 6.3) Obtain the first generation offspring population using selection, crossover, and mutation operations; 6.4) Merge the parent and offspring populations; 6.5) Perform fast non-dominated sorting and congestion calculation; 6.6) Select appropriate individuals based on non-dominance relationship and crowding degree to generate a new population; 6.7) Repeat the above steps to obtain all Pareto optimal solutions that meet the requirements; 6.8) Use Euclidean techniques to obtain dimensionless targets; 6.9) Use the TOPSIS decision method to rank the optimal solutions and select the solution that is closest to the ideal solution.

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