Load spectrum compilation method and compilation system for motor speed reducer for engineering machinery

Abstract

The invention relates to the technical field of engineering machinery, and discloses a motor reducer load spectrum compilation method and system for engineering machinery. According to the motor speed reducer load spectrum compilation method for the engineering machinery, a test working condition and a test item corresponding to a motor speed reducer load spectrum test are determined firstly, then a real vehicle test is performed, and pressure data and flow data of each oil port of the motor speed reducer are acquired through a data acquisition device; preprocessing the collected original data through data null drift processing, singular point data elimination and data filtering processing to obtain preprocessed data; carrying out data conversion on the preprocessed data, and carrying out data statistics on the converted data to obtain a statistical value; and on the basis of the statistical value, an eight-level load spectrum method and a conover rule are adopted to obtain a load spectrum of the motor speed reducer. The test of the working load spectrum of the motor reducer is realized, design guidance is provided, and the service life is prolonged.

Description

Technical Field

[0001] The present application belongs to the technical field of engineering machinery, and specifically relates to a method and system for compiling a load spectrum of a motor reducer for engineering machinery. Background Art

[0002] Excavators have harsh working conditions and complex loads. The motor reducer structure is prone to fatigue damage under the long-term action of random loads. The reducer load spectrum is the basic data for structural fatigue design and fatigue testing. For excavators, testing the travel reducer load spectrum is of great significance for guiding the motor reducer structure design, identifying design risks, and improving its performance and service life.

[0003] At present, the load spectrum test methods of excavators are all for external working devices. For example, by arranging pressure sensors and displacement sensors to synchronously measure the working device oil cylinder pressure and extension amount, the bucket tip load-time history and the load-time history of each hinge point of the working device are calculated, and the load spectrum of the whole machine and the load spectrum of the bucket arm are obtained from the load-time history. In addition, there is a Chinese patent with application number CN103217307A, published on July 24, 2013, and named "A load spectrum test method for hydraulic excavator working device", which realizes the test of bucket tip load spectrum by analyzing a typical posture of the working device and its stress state.

[0004] Although the prior art discloses an excavator load spectrum test method, they are all for the excavator's working cylinder and external working device, and do not involve the excavator's motor reducer, especially the specific test method of the reducer load spectrum. Since the operating conditions of the motor reducer are relatively complex, the existing method cannot be directly used for the specific test method of the reducer load spectrum. Therefore, there is an urgent need to provide a load spectrum test method for the motor reducer to guide the motor reducer structural design, design risk identification, and how to improve its performance and service life. Summary of the invention

[0005] The purpose of this application is to provide a method and system for compiling a load spectrum of a motor reducer for engineering machinery, which is used to implement a load spectrum testing method for a motor reducer, so as to guide the structural design of the motor reducer, realize design risk identification, and improve its performance and service life.

[0006] In order to achieve the above-mentioned purpose, the present application provides, on one hand, a method for compiling a load spectrum of a motor reducer for an engineering machinery, comprising:

[0007] S100: installing a pressure detector and a flow detector at each oil port of a motor reducer of the engineering machinery, and establishing a communication connection with the pressure detector and the flow detector through a data acquisition device;

[0008] S200: Determine the test conditions and test items corresponding to the motor reducer load spectrum test;

[0009] S300: carrying out a real vehicle test according to the determined test conditions and test items, and collecting, recording and saving the pressure data and flow data measured by the pressure detector and the flow detector through a data acquisition device;

[0010] S400: preprocessing the pressure data and the flow data to obtain preprocessed data, wherein the preprocessing includes data zero drift processing, singular point data removal and data filtering processing;

[0011] S500: performing data conversion on the preprocessed data, and performing data statistics on the converted data to obtain statistical values;

[0012] S600: Based on the statistical value, an eight-level load spectrum method and the Conover rule are used to obtain a motor reducer load spectrum.

[0013] As a further improvement of the above technical solution:

[0014] In some embodiments, step S200 includes:

[0015] The test working condition is selected as a typical working condition of a complete engineering machinery, and the typical working condition of a complete engineering machinery includes a dirt road working condition and a stone road working condition;

[0016] The test items include bilateral same-direction walking, unilateral driving, bilateral reverse walking, low-speed / high-speed gear switching, forward / reverse switching and climbing, and the proportion of each test item in the total working time of the whole machine is allocated.

[0017] In some implementations, before the actual vehicle test is carried out in step S300, the steps also include: setting the parameters of each acquisition channel of the data acquisition device, clearing the zero drift, and then carrying out the actual vehicle test according to the determined test conditions and the test items.

[0018] In some implementations, the step S400 includes:

[0019] S410: removing the pressure and flow data when not in operation from the collected original pressure data and flow data, and extracting effective pressure time domain and flow time domain data;

[0020] S420: performing zero drift processing by piecewise linearization zero drift theory to remove drift data in the original pressure data and flow data;

[0021] S430: using a differential gradient method or a Rheinland criterion to identify singular point data and remove the singular point data from the pressure data and the flow data after removing the drift signal;

[0022] S440: low-pass filtering is performed by using a high-order Butterworth filter to perform the data filtering process;

[0023] The data filtering process is used to remove noise data in the pressure data and the flow data to obtain pre-processed pressure and flow data, namely, the pre-processed data.

[0024] In some implementations, the preprocessing data in step S500 for data conversion includes:

[0025] The preprocessed data is converted into the input torque and speed of the motor reducer, wherein the conversion formula of the input torque and speed of the motor reducer is:

[0026]

[0027] Where, 1kgf.m = 9.8Nm; 1kgf / cm 2 =0.1MPa; 1cc / rev=ml / r; P is pressure; T is torque; q is the motor displacement in the motor reducer; η m is the mechanical efficiency; Q is the motor flow; N is the input speed of the motor reducer.

[0028] In some implementations, performing data statistics on the converted data to obtain statistical values ​​in step S500 includes:

[0029] S510: using the rain flow counting method to perform statistical counting, selecting the typical spectrum segment where the maximum peak and valley of the load spectrum start and end, inputting the peak and valley values ​​in sequence, and reading the peak or valley values ​​in sequence, simplifying the complex load time data into several load cycles through multiple conditional statements and assignments;

[0030] S520: Perform normal distribution fitting on the input torque and speed mean of the motor reducer in MATLAB software by using the rain flow counting method to obtain a normal probability graph.

[0031] In some embodiments, the step S600 includes:

[0032] S610: performing Weibull distribution and normal distribution fitting on the amplitude and mean of the converted input torque and speed of the motor reducer, respectively, to obtain a joint probability density function of the amplitude and mean;

[0033] S620: Obtaining an extension frequency of 10 according to the joint probability density function 6Extreme loads of amplitude and mean value;

[0034] S630: the amplitude of the load spectrum is divided into 8 levels according to the Conover rule, the ratio of the amplitude of each load to the extreme load of the amplitude is 1, 0.95, 0.85, 0.725, 0.575, 0.425, 0.275, 0.125, the mean is divided at equal intervals, and then the mean amplitude-frequency two-dimensional matrix is ​​obtained according to the joint probability density function, that is, a 8*8 two-dimensional load spectrum is obtained;

[0035] S640: converting the two-dimensional load spectrum into a one-dimensional load spectrum, thereby obtaining an eight-level one-dimensional load spectrum;

[0036] S650: Obtaining the total average value of all loads in the two-dimensional load spectrum as the fluctuation center, and superimposing the eight-level one-dimensional load spectrum on the fluctuation center during the fatigue test to obtain the program loading spectrum used for one cycle loading period of the input torque and speed of the motor reducer for the fatigue life test;

[0037] S660: After obtaining the program load spectrum, multiply each level of load by the same acceleration coefficient k to obtain the acceleration load spectrum of the motor reducer.

[0038] In some embodiments, the method for compiling a load spectrum of a motor reducer for engineering machinery further includes:

[0039] S700: Based on Miner's linear fatigue cumulative damage theory and the SN curve, and according to the specific values ​​of the acceleration load spectrum of the motor reducer and the specific values ​​of the program loading spectrum, the equivalent damage corresponding to one cycle of the acceleration load spectrum is obtained, and the equivalent life of the motor reducer corresponding to the acceleration load spectrum is known.

[0040] In some embodiments, the mathematical expression of Miner's law in the Miner linear fatigue cumulative damage theory is:

[0041]

[0042] Where n1, n2, ...n i To apply stresses σ1, σ2, …σ on the specimen i The actual number of cycles under 1,f 、N 2,f …N i,f are σ1, σ2, …σ i Stress fatigue life;

[0043] The SN curve is used to express the relationship between the applied load and the fatigue life of the specimen as follows:

[0044]

[0045] Where, T s is the load during the constant amplitude fatigue life test; T c is the strengthening load during the accelerated fatigue life test; K is the slope of the SN curve; N c is the life of the accelerated fatigue test; N s is the life during the constant amplitude fatigue life test.

[0046] The second aspect of the present application further provides a system for compiling a load spectrum of a motor reducer for an engineering machinery, which applies the method for compiling a load spectrum of a motor reducer for an engineering machinery provided in the first aspect. The system for compiling a load spectrum of a motor reducer for an engineering machinery comprises:

[0047] Pressure detector;

[0048] Flow detector;

[0049] A motor reducer, each oil port of which is provided with the pressure detector and the flow detector;

[0050] A data acquisition device, which is in communication with each of the pressure detectors and the flow detectors, and is used to acquire, record and save the pressure data and flow data measured by the pressure detectors and the flow detectors;

[0051] A host computer is communicatively connected with the data acquisition device, and is configured to perform data preprocessing, data conversion, data statistics and equivalent calculation of load spectrum according to the pressure data and the flow data, and output the motor reducer load spectrum.

[0052] Compared with the prior art, the present application provides a method and system for compiling a load spectrum of a motor reducer for construction machinery. The method for compiling a load spectrum of a motor reducer for construction machinery first determines the test conditions and test items corresponding to the load spectrum test of the motor reducer, then conducts a real vehicle test, and collects the pressure data and flow data of each oil port of the motor reducer through a data acquisition device, and then pre-processes the collected raw data through data zero drift processing, singular point data removal and data filtering processing to obtain pre-processed data; then the pre-processed data is converted, and the converted data is statistically analyzed to obtain statistical values; based on the statistical values, the load spectrum of the motor reducer is obtained by using the eight-level load spectrum method and the conover rule.

[0053] Thus, the method for compiling the load spectrum of the motor reducer for engineering machinery provided in the present application solves the problem that the working load spectrum of the motor reducer is difficult to measure directly, and has the following advantages:

[0054] (1) The test conditions of construction machinery are fully considered, and the test conditions are more in line with the actual operating conditions of construction machinery. The test results are closer to the load spectrum in actual operation. It can provide a more accurate design basis for the design of motor reducers for construction machinery.

[0055] (2) The actual measurement and theoretical calculation of the motor reducer load spectrum are cross-checked. Through this test method and compilation system, it is possible to provide optimization direction for the motor reducer simulation model parameters, obtain more accurate simulation experience values, accumulate experience for future theoretical calculations, provide more meaningful guidance, and thus improve the design performance of the motor reducer and extend its service life.

[0056] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without creative work. In the drawings:

[0058] Figure 1 A structural block diagram of a system for compiling a load spectrum of a motor reducer for an engineering machinery provided in an embodiment of the present application;

[0059] Figure 2 A schematic diagram of the structure of a system for compiling a load spectrum of a motor reducer for an engineering machinery provided in an embodiment of the present application;

[0060] Figure 3 A flow chart of a method for compiling a load spectrum of a motor reducer for an engineering machinery provided in an embodiment of the present application;

[0061] Figure 4 A data preprocessing flow chart of a method for compiling a load spectrum of a motor reducer for an engineering machinery provided in an embodiment of the present application;

[0062] Figure 5 A flowchart of the rain flow counting method in the method for compiling a load spectrum of a motor reducer for engineering machinery provided in an embodiment of the present application.

[0063] Description of Reference Numerals

[0064] 1. Motor reducer; 2. Pressure detector; 3. Flow detector; 4. Data acquisition device; 5. Host computer. DETAILED DESCRIPTION

[0065] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0066] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with exemplary embodiments.

[0067] See also Figure 1 and Figure 2 This embodiment provides a load spectrum compilation system for a motor reducer for engineering machinery, which can be used to test and compile a load spectrum of a motor reducer 1.

[0068] The load spectrum compilation system of a motor reducer for construction machinery comprises a pressure detector 2 , a flow detector 3 , a motor reducer 1 and a host computer 5 .

[0069] It should be noted that the motor reducer 1 may be provided with a plurality of oil ports, including a first working oil port, a second working oil port, and an oil discharge port. In some embodiments, the plurality of oil ports may also include a third working oil port, a fourth working oil port, or oil ports with other functions. In this embodiment, the number of oil ports of the motor reducer 1 is not limited.

[0070] The pressure detector 2 and the flow detector 3 are arranged corresponding to the oil ports of the motor reducer 1, that is, each oil port of the motor reducer 1 is individually configured with a pressure detector 2 and a flow detector 3. The pressure detector 2 and the flow detector 3 are used to detect the pressure data and flow data of the corresponding oil ports.

[0071] Optionally, the pressure detector 2 may be a pressure gauge or a pressure sensor, and the flow detector 3 may be a flow meter. It should be understood that the above is only an example and is not intended to limit the scope of protection of the present application.

[0072] The data acquisition device 4 is connected to each pressure detector 2 and flow detector 3 by communication, such as wired communication connection or wireless communication connection. The data acquisition device 4 is used to collect, record and save the pressure data and flow data measured by the pressure detector 2 and flow detector 3.

[0073] The host computer 5 is connected to the data acquisition device 4 by communication, such as wired communication connection or wireless communication connection. The host computer 5 is configured to perform data preprocessing, data conversion, data statistics and equivalent calculation of load spectrum according to pressure data and flow data, and output the load spectrum of the motor reducer 1.

[0074] The construction machinery may be a crane or an excavator, etc. The motor reducer 1 may be a travel motor reducer 1 or a rotary motor reducer 1 .

[0075] See also Figure 1 , Figure 2 and Figure 3 Furthermore, this embodiment also provides a method for compiling a load spectrum of a motor reducer for an engineering machinery. The method for compiling a load spectrum of a motor reducer for an engineering machinery comprises the following steps:

[0076] S100: A pressure detector 2 and a flow detector 3 are respectively installed at each oil port of the motor reducer 1 of the engineering machinery, and a communication connection is established between the pressure detector 2 and the flow detector 3 via the data acquisition device 4 .

[0077] In this embodiment, when performing the load spectrum test method for the motor reducer for process machinery, it is necessary to first build a compilation system, specifically, first install the pressure detector 2 and the flow detector 3 at each oil port of the motor reducer 1, and realize the construction of the communication channel between the pressure detector 2, the flow detector 3 and the data acquisition device 4, and the construction of the communication channel between the data acquisition device 4 and the host computer 5. To ensure that data information can be transmitted normally.

[0078] It should be noted that the measuring range of each pressure detector 2 must be adapted to the pressure of the oil port being measured. Similarly, the measuring range of the flow detector 3 must be adapted to the pressure of the oil port being measured, so as to ensure that data of various working conditions can be collected normally.

[0079] S200: Determine the test conditions and test items corresponding to the load spectrum test of the motor reducer 1.

[0080] In this embodiment, in order to ensure that the load spectrum of the motor reducer 1 obtained from the test can be as close as possible to the actual working state of the whole machine, the working condition of the test machine should select the typical working condition of the whole construction machinery, and the operation process should be as close as possible to the customer's working condition and operating habits without deliberate human control.

[0081] Among them, the typical working conditions of the whole construction machinery include dirt road conditions and stone road conditions. Dirt road conditions and stone road conditions are common working conditions, such as flat and soft dirt road conditions and relatively flat stone roads composed of a mixture of gravel and stones.

[0082] Furthermore, the test items include bilateral same-direction walking, unilateral driving, bilateral reverse walking, low-speed / high-speed gear switching, forward / reverse switching and climbing, and the proportion of each test item in the total working time of the whole machine is allocated.

[0083] Determine the time distribution ratio of each action of motor reducer 1: the walking action of the construction machinery (life requirement of motor reducer 1) accounts for 10% of the total working time of the whole machine. Further allocate the time ratio of each walking action of the construction machinery, among which unilateral reverse accounts for 20% of the total walking action time, and the walking reducers on the left and right sides are calculated as 10% each, etc.

[0084] S300: Carry out actual vehicle testing according to the determined test conditions and test items, and collect, record and save the pressure data and flow data measured by the pressure detector 2 and the flow detector 3 through the data acquisition device 4.

[0085] S400: Preprocessing the pressure data and the flow data to obtain preprocessed data, wherein the preprocessing includes data zero drift processing, singular point data removal and data filtering processing.

[0086] S500: Perform data conversion on the preprocessed data, and perform data statistics on the converted data to obtain statistical values.

[0087] S600: Based on the statistical value, the load spectrum of the motor reducer 1 is obtained by using the eight-level load spectrum method and the Conover rule.

[0088] Furthermore, before the actual vehicle test is carried out in the above step S300, the following steps are also included: setting the parameters of each acquisition channel of the data acquisition device 4, clearing the zero drift, and then carrying out the actual vehicle test according to the determined test conditions and test items. During the actual vehicle test, the test is carried out according to the determined test conditions, the test items and the action time distribution ratio in Table 1.

[0089] Please also read Figure 4 The above step S400 mainly performs data preprocessing, including the following steps:

[0090] S410: Remove the pressure and flow data when not in operation from the collected original pressure data and flow data, and extract effective pressure time domain and flow time domain data.

[0091] S420: Zero drift processing is then performed using piecewise linearization zero drift theory to remove drift data from the original pressure data and flow data.

[0092] S430: Using a differential gradient method or a Rheinland criterion to identify singular point data and eliminate singular point data from the pressure data and flow data after removing the drift signal.

[0093] S440: Perform data filtering processing by performing low-pass filtering using a high-order Butterworth filter.

[0094] It can be understood that the above steps S410 to S440 can be summarized as: original data - extracting effective data - removing zero drift - removing singular points - filtering - obtaining preprocessed data. Among them, data filtering is used to remove noise data in pressure data and flow data to obtain preprocessed pressure and flow data, that is, preprocessed data.

[0095] The data conversion of the pre-processed data in the above step S500 includes: converting the pre-processed data into the input torque and speed of the motor reducer 1. The conversion formulas of the input torque and speed of the motor reducer 1 are the following formulas (1) and (2):

[0096]

[0097] Where, 1kgf.m = 9.8Nm; 1kgf / cm 2 =0.1MPa; 1cc / rev=ml / r; P is pressure; T is torque; q is the motor displacement in the motor reducer 1; η m is the mechanical efficiency; Q is the motor flow; N is the input speed of the motor reducer 1.

[0098] Please also read Figure 5 Further, in step S500, performing data statistics on the converted data to obtain statistical values ​​includes the following steps:

[0099] S510: Use the rain flow counting method to perform statistical counting, select the typical spectrum segment where the maximum peak and valley of the load spectrum start and end, input the peak and valley values ​​in sequence, and read the peak or valley values ​​in sequence. Through multiple conditional statements and assignments, the complex load time data is simplified into several load cycles. Figure 5 The process in .

[0100] S520: Perform normal distribution fitting on the input torque and speed mean of the motor reducer 1 in MATLAB software by using the rain flow counting method to obtain a normal probability graph.

[0101] In the above step S600, the "eight-level load spectrum method" is used to compile the input torque and speed of the motor reducer 1 after preprocessing, conversion and statistics. Specifically, step S600 includes the following steps:

[0102] S610: Perform Weibull distribution and normal distribution fitting on the amplitude and mean of the converted input torque and speed of the motor reducer 1, respectively, to obtain a joint probability density function of the amplitude and mean.

[0103] S620: Obtaining an extension frequency of 10 according to the joint probability density function 6 The extreme load of amplitude and mean. Among them, the statistical point of view is that 10 6 The cycles are sufficiently representative for all loads including the most severe cases which rarely occur.

[0104] S630: Then divide the amplitude of the load spectrum into 8 levels according to the Conover rule, and the ratio of the amplitude of each level of load to the extreme load of the amplitude is 1, 0.95, 0.85, 0.725, 0.575, 0.425, 0.275, 0125, and the mean is divided according to equal intervals. Then, the mean amplitude-frequency two-dimensional matrix is ​​obtained according to the joint probability density function, that is, the 8*8 type two-dimensional load spectrum is obtained. Among them, the coefficient of the Conover rule is the standard value. In the process of compiling the eight-level load spectrum, the Conover rule is used to divide the amplitude into non-equal intervals; and the extreme load of the original load spectrum amplitude is multiplied by the corresponding coefficient to obtain the load amplitude of each level in the eight-level load spectrum.

[0105] S640: Convert the two-dimensional load spectrum into a one-dimensional load spectrum to obtain an eight-level one-dimensional load spectrum. Among them, the amplitude of each load in the one-dimensional load spectrum follows the amplitude classification in the two-dimensional load spectrum, and the frequency is the sum of the mean frequencies of each level corresponding to the amplitude in the two-dimensional load, to obtain an eight-level one-dimensional load spectrum. S650: Obtain the total average value of all loads in the two-dimensional load spectrum as the fluctuation center. During the fatigue test, the eight-level one-dimensional load spectrum is superimposed on the fluctuation center to obtain the input torque and speed of the motor reducer 1 for a cycle loading cycle of the fatigue life test. Among them, superimposing on the fluctuation center can be understood as: for example, if the amplitude is 10 and the fluctuation center is 5, the value of the superimposed load spectrum is 15.

[0106] S660: After obtaining the program load spectrum, multiply each level of load by the same acceleration coefficient k to obtain the acceleration load spectrum of the motor reducer 1.

[0107] It can be understood that the program load spectrum can be considered as the information such as the parameters and numerical values ​​applied by the mobile dynamometer to the target during the bench test. The acceleration coefficient k value needs to be selected according to actual needs. After multiplying by the acceleration coefficient k, the accelerated load spectrum obtained is compared with the original program load spectrum. The equivalent damage represented by the accelerated load spectrum is greater, and the number of loading cycles required during bench loading is less, thereby shortening the bench test time.

[0108] Furthermore, the method for compiling a load spectrum of a motor reducer for engineering machinery provided in this embodiment also includes step S700.

[0109] S700: Based on Miner's linear fatigue cumulative damage theory and SN curve, and according to the specific values ​​of the acceleration load spectrum and the specific values ​​of the program loading spectrum of the motor reducer 1, the equivalent damage corresponding to one cycle of the acceleration load spectrum is obtained, and the equivalent life of the motor reducer 1 corresponding to the acceleration load spectrum can be known.

[0110] Among them, in the SN curve, S represents amplitude and N represents number of cycles, which indicates that when the specimen is loaded with amplitude S and the number of loading times is N, fatigue failure occurs to the specimen; Miner linear fatigue cumulative damage theory, that is, different load amplitudes have their corresponding number of cycles to reach fatigue life. The number of loadings of each load amplitude is divided by the corresponding number of cycles N, and then added separately. When the value reaches 1, the specimen is considered to have fatigue failure.

[0111] It should be noted that the life in step S700 is calculated based on the equivalent damage theory. For example, the fatigue cumulative damage of the load spectrum actually collected is 0.2, and the equivalent damage corresponding to the accelerated load spectrum is twice the original load spectrum, and the time is 5h. Then the reducer life corresponding to the accelerated load spectrum is 1 / 0.4=2.5 cycles, and the time is 12.5h. It should be understood that the above is only an example and is not intended to limit the scope of protection of this application.

[0112] Miner linear fatigue cumulative damage theory: i strain and stress cycles with the same strain amplitude and average stress will be accumulated linearly, resulting in n i / N i,f Damage, that is, consumption of n i / N i,f Partial life; when the damage accumulates linearly to 1, fatigue failure will occur.

[0113] The SN curve is the relationship between the applied load on the specimen (how is it related to the reducer here) and the fatigue life of the specimen. The damage equivalence relationship of the SN curve obtains the number of material failure cycles corresponding to each amplitude load of the accelerated load spectrum, that is, the size of the specimen life corresponding to a certain amplitude load level.

[0114] It should be noted that the "test piece" described above may refer to any mechanical part on the motor reducer. If the object of study is a gear, the test piece refers to the gear; if the object of study is an output shaft or a housing, the test piece refers to the output shaft or the housing.

[0115] Specifically, the mathematical expression of Miner's law in Miner's linear fatigue cumulative damage theory is as follows:

[0116]

[0117] In formula (3), n1, n2, ... n i To apply stresses σ1, σ2, …σ on the specimen i The actual number of cycles under 1,1 、N 2,f …N i,f are σ1, σ2, …σ i Stress fatigue life;

[0118] The SN curve is used to express the relationship between the applied load and the fatigue life of the specimen as follows:

[0119]

[0120] In formula (4), T s is the load during the constant amplitude fatigue life test; T c is the strengthening load during the accelerated fatigue life test; K is the slope of the SN curve; N c is the life of the accelerated fatigue test; N s is the life during the constant amplitude fatigue life test.

[0121] The above formula (4) is derived from the expression of the SN curve, which is S K N=C, the damage equivalent is After transformation, we get the above formula (4). Where S is the amplitude; K is the slope of the SN curve; N is the number of cycles; and C is a constant.

[0122] The method for compiling a load spectrum of a motor reducer for engineering machinery provided in this embodiment solves the problem that the working load spectrum of the motor reducer 1 is difficult to measure directly, and has the following advantages:

[0123] (1) The test conditions of engineering machinery are fully considered, the test conditions are more in line with the actual operating conditions of engineering machinery, and the test results are closer to the load spectrum in actual operation. It can provide a more accurate design basis for the design of the motor reducer 1 of the engineering machinery.

[0124] (2) The actual measurement and theoretical calculation of the load spectrum of the motor reducer 1 are mutually verified. Through this test method and compilation system, it is possible to provide optimization direction for the simulation model parameters of the motor reducer 1, obtain more accurate simulation experience values, accumulate experience for future theoretical calculations, provide more meaningful guidance, and thus improve the design performance of the motor reducer 1 and extend its service life.

[0125] An embodiment of the present application also provides a machine-readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the method for compiling a load spectrum of a motor reducer for an engineering machinery provided in the above embodiment.

[0126] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0127] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0128] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0129] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0130] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0131] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0132] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0133] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0134] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for compiling a load spectrum of a motor reducer for construction machinery, characterized in that: include: S100: installing a pressure detector and a flow detector at each oil port of a motor reducer of the engineering machinery, and establishing a communication connection with the pressure detector and the flow detector through a data acquisition device; S200: Determine the test conditions and test items corresponding to the motor reducer load spectrum test; S300: carrying out a real vehicle test according to the determined test conditions and test items, and collecting, recording and saving the pressure data and flow data measured by the pressure detector and the flow detector through a data acquisition device; S400: preprocessing the pressure data and the flow data to obtain preprocessed data, wherein the preprocessing includes data zero drift processing, singular point data removal and data filtering processing; S500: performing data conversion on the preprocessed data, and performing data statistics on the converted data to obtain statistical values; S600: Based on the statistical value, an eight-level load spectrum method and the Conover rule are used to obtain a motor reducer load spectrum.

2. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 1, characterized in that: The step S200 includes: The test working condition is selected as a typical working condition of a complete engineering machinery, and the typical working condition of a complete engineering machinery includes a dirt road working condition and a stone road working condition; The test items include bilateral same-direction walking, unilateral driving, bilateral reverse walking, low-speed / high-speed gear switching, forward / reverse switching and climbing, and the proportion of each test item in the total working time of the whole machine is allocated.

3. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 1, characterized in that: Before carrying out the actual vehicle test in step S300, the steps also include: setting the parameters of each acquisition channel of the data acquisition device, clearing the zero drift, and then carrying out the actual vehicle test according to the determined test conditions and the test items.

4. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 1, characterized in that: The step S400 includes: S410: removing the pressure and flow data when not in operation from the collected original pressure data and flow data, and extracting effective pressure time domain and flow time domain data; S420: performing zero drift processing by piecewise linearization zero drift theory to remove drift data in the original pressure data and flow data; S430: using a differential gradient method or a Rheinland criterion to identify singular point data and remove the singular point data from the pressure data and the flow data after removing the drift signal; S440: low-pass filtering is performed by using a high-order Butterworth filter to perform the data filtering process; The data filtering process is used to remove noise data in the pressure data and the flow data to obtain pre-processed pressure and flow data, namely, the pre-processed data.

5. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 1, characterized in that: The data conversion of the pre-processed data in step S500 includes: The preprocessed data is converted into the input torque and speed of the motor reducer, wherein the conversion formula of the input torque and speed of the motor reducer is: Where, 1kgf.m = 9.8Nm; 1kgf / cm 2 =0.1MPa; 1cc / rev=ml / r; P is pressure; T is torque; q is the motor displacement in the motor reducer; η m is the mechanical efficiency; Q is the motor flow; N is the input speed of the motor reducer.

6. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 5, characterized in that: In step S500, the converted data is statistically analyzed to obtain statistical values, including: S510: using the rain flow counting method to perform statistical counting, selecting the typical spectrum segment where the maximum peak and valley of the load spectrum start and end, inputting the peak and valley values ​​in sequence, and reading the peak or valley values ​​in sequence, simplifying the complex load time data into several load cycles through multiple conditional statements and assignments; S520: Perform normal distribution fitting on the input torque and speed mean of the motor reducer in MATLAB software by using the rain flow counting method to obtain a normal probability graph.

7. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 5, characterized in that: The step S600 includes: S610: performing Weibull distribution and normal distribution fitting on the amplitude and mean of the converted input torque and speed of the motor reducer, respectively, to obtain a joint probability density function of the amplitude and mean; S620: Obtaining an extension frequency of 10 according to the joint probability density function 6 Extreme loads of amplitude and mean value; S630: the amplitude of the load spectrum is divided into 8 levels according to the Conover rule, the ratio of the amplitude of each load to the extreme load of the amplitude is 1, 0.95, 0.85, 0.725, 0.575, 0.425, 0.275, 0.125, the mean is divided at equal intervals, and then the mean amplitude-frequency two-dimensional matrix is ​​obtained according to the joint probability density function, that is, a 8*8 two-dimensional load spectrum is obtained; S640: converting the two-dimensional load spectrum into a one-dimensional load spectrum, thereby obtaining an eight-level one-dimensional load spectrum; S650: Obtaining the total average value of all loads in the two-dimensional load spectrum as the fluctuation center, and superimposing the eight-level one-dimensional load spectrum on the fluctuation center during the fatigue test to obtain the program loading spectrum used for one cycle loading period of the input torque and speed of the motor reducer for the fatigue life test; S660: After obtaining the program load spectrum, multiply each level of load by the same acceleration coefficient k to obtain the acceleration load spectrum of the motor reducer.

8. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 7, characterized in that: The method for compiling a load spectrum of a motor reducer for engineering machinery also includes: S700: Based on Miner's linear fatigue cumulative damage theory and the SN curve, and according to the specific values ​​of the acceleration load spectrum of the motor reducer and the specific values ​​of the program loading spectrum, the equivalent damage corresponding to one cycle of the acceleration load spectrum is obtained, and the equivalent life of the motor reducer corresponding to the acceleration load spectrum is known.

9. The method for compiling a load spectrum of a motor reducer for construction machinery according to claim 8, characterized in that: The mathematical expression of Miner's law in the Miner linear fatigue cumulative damage theory is: Where n1, n2, ...n i To apply stress σ1, σ2, ....σ on the specimen i The actual number of cycles under 1，f 、N 2， f ...N i，f is σ1, σ2, ....σ i Stress fatigue life; The SN curve is used to express the relationship between the applied load and the fatigue life of the specimen as follows: Where, T s is the load during the constant amplitude fatigue life test; T c is the strengthening load during the accelerated fatigue life test; K is the slope of the SN curve; N c is the life of the accelerated fatigue test; N s is the life during the constant amplitude fatigue life test.

10. A system for compiling load spectrum of motor reducer for construction machinery, characterized in that: The method for compiling a load spectrum of a motor reducer for an engineering machinery according to any one of claims 1 to 9 is applied, and the load spectrum compilation system for a motor reducer for an engineering machinery comprises: Pressure detector; Flow detector; A motor reducer, each oil port of which is provided with the pressure detector and the flow detector; A data acquisition device, which is in communication with each of the pressure detectors and the flow detectors, and is used to acquire, record and save the pressure data and flow data measured by the pressure detectors and the flow detectors; A host computer is communicatively connected with the data acquisition device, and is configured to perform data preprocessing, data conversion, data statistics and equivalent calculation of load spectrum according to the pressure data and the flow data, and output the motor reducer load spectrum.

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