A load torque measuring device for tractors

Abstract

The present invention discloses a load torque measurement device for tractors, comprising a rotational speed sensor, a connecting device, a measurement module, and a data processing module. The device is connected in series between the universal joint of the tractor's power output shaft and the drive shaft of an agricultural implement via the connecting device. The device is used to study the dynamic changes in the tractor's load torque during actual production operations, thereby enabling real-time monitoring and precise control of load torque changes in complex operating conditions. This device overcomes the shortcomings of existing torque sensor signal lag, traditional strain gauge torque measurement methods that are limited by factors such as humidity, temperature, and adhesives, and have poor anti-interference capabilities. It can measure the load torque of a tractor in real time under actual operating conditions, requires minimal alignment, and offers high measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery engineering, and in particular to a load torque measuring device for a tractor. Background Art

[0002] Currently, my country's tractors generally use a single-pump fuel injection system with open-loop and extensive control. Tractor operation quality is significantly affected by the driver's skill level. Furthermore, tractor operating environments are complex, and engine loads fluctuate dramatically. In actual production, tractors often face problems such as unstable power output, high fuel consumption, and poor emissions, resulting in significant economic and environmental losses. Against this backdrop, agricultural equipment must be guided by information technology and upgraded towards intelligence and automation. Research is being conducted on convenient and accurate load torque measurement devices for tractors. Research is being conducted on new intelligent agricultural diesel engine control strategies based on load torque models. These strategies can predict load torque changes caused by changes in agricultural implements and soil conditions, implement feedforward-feedback composite control of diesel engine power output, and improve diesel engine power performance and adaptability to agricultural operating conditions. This will further enhance the efficiency and performance of agricultural equipment, reduce agricultural machinery operating costs, and promote the transformation and upgrading of the agricultural equipment industry structure, ultimately achieving sustainable development. Summary of the Invention

[0003] The purpose of the present invention is to provide a load torque measurement device for a tractor, aiming to provide a way to obtain the load torque for a new intelligent agricultural diesel engine control strategy based on a load torque model.

[0004] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0005] A load torque measuring device for a tractor, comprising a rotational speed sensor, a connecting device, a measuring module, and a data processing module, wherein the load torque measuring device for a tractor is serially connected between a universal joint of a tractor power output shaft and a drive shaft of an agricultural implement via the connecting device, wherein:

[0006] The speed sensor is a unipolar Hall sensor, including a sensor, a signal disk, and a loading device. The signal disk is fixed on the measuring shaft. The sensor detects the changing magnetic field signal generated by the rotation of the signal disk and outputs a pulse signal representing the speed of the universal joint. The pulse signal is sent via GPRS and interacts with the data processing module. The speed measurement method is specifically as follows:

[0007] A magnetic marker is provided on the signal disk. When the shaft rotates, the magnetic marker is driven to rotate. The sensor detects the magnetic signal generated by the rotation of the magnetic marker and outputs a jump signal. The frequency of the jump signal can represent the rotation speed. To increase the measurement accuracy, multiple magnetic markers are evenly arranged on the signal disk, and the frequency of the jump signal is averaged.

[0008] The loading device meets the requirements of bench testing and is directly placed on the test bench or on a rack connected to the bench. The speed parameters are input through the industrial computer interface, and the loading device controls the loaded torque (N·m), thereby controlling the speed.

[0009] The connecting device includes a flange, a universal joint shaft assembly and a measuring shaft, wherein the universal joint shaft assembly adopts a ball cage elastic coupling to reduce the torsional vibration amplitude and the impact caused by dynamic load, prevent the occurrence of additional resistance and additional mechanical vibration, and improve the stability of output power.

[0010] The measuring device includes a measuring chamber, a measuring circuit, and a temperature sensor. The measuring chamber is composed of two rotating rings that rotate synchronously with the shaft. The rotating rings are fixed to the middle section of the measuring shaft via a key connection, and the rotating rings are meshed through a 45-degree toothed structure on the edge. Resistive strain gauges are attached to the rotating rings to form a bridge circuit. The output end of the bridge circuit is connected to a signal amplification circuit and sent to a data processing platform via GPRS for reception and processing.

[0011] The torque measurement method is as follows:

[0012] An AC unbalanced bridge is used for measuring dynamic torque parameters. The first bridge arm is connected to a resistance strain gauge, and the other three bridge arms are connected to fixed resistors. Because the line connecting the initial meshing points between the rotating rings is not strictly perpendicular to the axis of the measured shaft, when the measured shaft rotates at speed n and no torque occurs, the AC unbalanced bridge is also in an unbalanced condition, with an initial output voltage U0. When the measured shaft undergoes torque, the meshing points between the rotating rings deviate from the initial position to the next position, and the voltage value changes to U. This voltage is transmitted to an industrial computer for analysis and processing. The torque signal acting on the measured shaft is measured by measuring the voltage values ​​U0 and U. The amplified output voltage and the standard torque value are calibrated. During formal experiments, the load torque can be obtained by querying the calibration table.

[0013] In order to increase the measurement accuracy, a signal amplification circuit containing an AC amplifier is selected to amplify the weak output signal inside the sensor. Multiple sets of identical strain measurement circuits are set on the measuring chamber teeth, and the data processing module calculates the average value of multiple sets of output electrical signals.

[0014] The temperature sensor in the measuring device is arranged on the universal joint shaft, collects electrical signals, and transmits them to the data processing module via GPRS. The industrial computer integrates and calibrates the electrical signal data representing the temperature to obtain the relationship between voltage and temperature. In the formal measurement, the industrial computer corrects the torque signal according to the signal transmitted by the temperature sensor, thereby eliminating the influence of temperature on the torque measurement.

[0015] The data processing module includes an industrial computer and a cloud service platform. The cloud service platform processes the electrical signals transmitted by the speed sensor and measurement module to obtain and display the tractor engine output shaft speed, the temperature of the universal joint, and the loading torque of the loading device during bench testing. The cloud service platform software monitors and modifies speed and torque data in real time, corrects torque data based on temperature data to eliminate temperature effects, and calibrates the amplified output voltage and standard torque value. During formal experiments, torque can be obtained by querying the calibration table. Testers can download and save torque data from the cloud service platform to mobile devices such as mobile phones, computers, and tablets via 4G / 5G / Wi-Fi signals.

[0016] The present invention's tractor load torque measurement device boasts a simple structure and ease of use. It overcomes the signal hysteresis of existing torque sensors, the limitations of traditional strain gauge torque measurement methods due to factors such as humidity, temperature, and adhesives, and their poor anti-interference capabilities. It measures the load torque of tractors in real time under actual operating conditions, requires minimal alignment, and offers high measurement accuracy. It supports automatic online data processing via a cloud service platform and can be downloaded to mobile devices via 4G, 5G, and Wi-Fi signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a general structural block diagram of the load torque measuring device for tractors of the present invention.

[0018] Figure 2 It is a schematic diagram of the speed sensor structure.

[0019] Figure 3 2 is a schematic structural diagram of a load torque measuring device for a tractor according to an embodiment of the present invention.

[0020] Figure 4 This is a three-dimensional schematic diagram of the measurement cabin.

[0021] Figure 5 This is the circuit diagram of an unbalanced bridge.

[0022] The marks in the figure represent:

[0023] 1. Speed ​​sensor, 101. Signal disk, 102. Sensor, 103. Loading device; 2. Connecting device, 201. Flange, 202. Universal joint shaft assembly, 203. Measuring shaft; 3. Measuring module, 301. Measuring cabin; 302. Measuring circuit; 303. Temperature sensor; 4. Data processing module; 401. Industrial computer; 402. Cloud service platform.

[0024] The present invention will be described in further detail below with reference to the accompanying drawings and examples. DETAILED DESCRIPTION

[0025] The applicant's research and development idea is to design a load torque measuring device for tractors, which can be used to study the dynamic changes of the load torque of tractors during actual production work, thereby realizing real-time monitoring and precise control of the changes in the load torque of tractors in complex operating conditions.

[0026] like Figure 1 As shown, this embodiment provides a load torque measuring device for a tractor, comprising a rotational speed sensor 1, a connecting device 2, a measuring module 3, and a data processing module 4. The load torque measuring device for a tractor is connected in series between the universal coupling of the tractor's power output shaft and the agricultural implement drive shaft via the connecting device 2.

[0027] like Figure 1-2 As shown, in this embodiment, the speed sensor 1 is a unipolar Hall sensor, including a signal disk 101, a sensor 102 and a loading device 103; the signal disk 101 is fixed on the measuring shaft 203, and the sensor 102 detects the changing magnetic field signal generated by the rotation of the signal disk 101, outputs a pulse signal representing the speed of the universal joint, and sends it via GPRS to interact with the data processing module 4.

[0028] The speed measurement method is as follows:

[0029] A magnetic marker is provided on the signal disk. When the shaft rotates, the magnetic marker is driven to rotate. The sensor 102 detects the magnetic signal generated by the rotation of the magnetic marker and outputs a jump signal. The frequency of the jump signal can represent the rotation speed. To increase the measurement accuracy, multiple magnetic markers are evenly arranged on the signal disk 101, and the frequency of the jump signal is averaged.

[0030] The loading device 103 can meet the bench test and be directly arranged on the test bench or a rack connected to the bench. The speed parameter is input through the industrial computer interface. The loading device 103 controls the loaded torque (N·m) and thus controls the speed.

[0031] like Figure 3 As shown, the connecting device 2 includes a flange 201, a universal joint shaft assembly 202 and a measuring shaft 203; in this embodiment, the universal joint shaft assembly 202 adopts a ball cage elastic coupling to reduce the torsional vibration amplitude and the impact caused by dynamic loads, prevent the occurrence of additional resistance and additional mechanical vibration, and improve the stability of the output power.

[0032] like Figure 3-4As shown, the measuring device 3 includes a measuring chamber 301, a measuring circuit 302 and a temperature sensor 303; the measuring chamber 301 is composed of two rotating rings that rotate synchronously with the shaft, the rotating rings are fixed to the middle section 203 of the measuring shaft by a key connection, the rotating rings are engaged by a 45° tooth structure on the edge, and a resistive strain gauge is pasted on the rotating ring to form a bridge circuit. The output end of the bridge circuit is connected to a signal amplification circuit and sent to the data processing platform 4 via GPRS, which receives and processes the signal.

[0033] The torque measurement method is as follows:

[0034] An AC unbalanced bridge is used for measuring dynamic torque parameters. The first bridge arm is connected to a resistance strain gauge R1, and the other three bridge arms are connected to fixed resistors. Because the line connecting the initial meshing points between the rotating rings is not strictly perpendicular to the axis of the measured shaft, when the measured shaft rotates at speed n and no torque occurs, the bridge is also in an unbalanced condition, with an initial output voltage U0. When the measured shaft undergoes torque, the meshing points between the rotating rings deviate from the initial position to the next position, and the voltage value changes to U. This voltage is transmitted to an industrial computer for analysis and processing. The torque signal acting on the measured shaft is measured by measuring the voltage values ​​U0 and U. The amplified output voltage and the standard torque value are calibrated. During formal experiments, the load torque can be obtained by querying the calibration table.

[0035] In order to increase the measurement accuracy, a signal amplification circuit including an AC amplifier is selected to amplify the weak output signal inside the sensor. In this embodiment, multiple groups of identical strain measurement circuits are set on the teeth of the measuring chamber 301, and the data processing module 4 calculates the average value of the multiple groups of output electrical signals.

[0036] The distance S between the measurement chambers 301 is determined according to actual conditions, but should not be too large.

[0037] like Figure 5 As shown, the measuring device uses an AC unbalanced bridge. When the strain gauge generates strain, the strain gauge generates a resistance change of △R1, and the bridge is in an unbalanced state. At this time:

[0038]

[0039] Assumptions And considering the initial balance condition of the bridge Omit the trace amount in the denominator The above formula can be written as:

[0040]

[0041] It can be seen from the formula that the output voltage is proportional to the resistance change generated by R1 when the strain gauge is strained. The processed voltage signal is then calibrated with the strain amount so that the load torque signal is proportional to the output voltage.

[0042] like Figure 3 As shown, in this embodiment, the temperature sensor 303 in the measuring device is arranged on the measuring shaft 203, collects electrical signals, and transmits them to the data processing module 4 via GPRS. The industrial computer 401 integrates and calibrates the electrical signal data representing the temperature to obtain the relationship between voltage and temperature. In the formal measurement, the industrial computer 401 corrects the torque signal according to the signal transmitted by the temperature sensor 303, thereby eliminating the influence of temperature on the torque measurement.

[0043] The data processing module 4 includes an industrial computer 401 and a cloud service platform 402. Cloud service platform 402 processes the electrical signals transmitted by the speed sensor 1 and the measurement module 3 to obtain and display the tractor engine output shaft speed, the universal joint temperature, and the loading torque of the loading device 103 during bench testing. The cloud service platform software monitors and modifies speed and torque data in real time, corrects torque data based on temperature data to eliminate temperature effects, and calibrates the amplified output voltage and standard torque value. During formal experiments, torque can be obtained by querying the calibration table. Testers can download and save torque data from cloud service platform 402 to mobile devices such as mobile phones, computers, and tablets via 4G / 5G / WIFI signals.

[0044] The load torque measuring device for tractors provided in this embodiment has the following working process:

[0045] After the tractor load torque measurement device is installed and adjusted, a preliminary test should be performed to calibrate the output voltage and temperature. During the actual measurement, the device is powered on, entering a standby state and waiting for the tractor to operate. At this point, because the line connecting the initial meshing points between the rotating rings of the measuring chamber is not strictly perpendicular to the axis of the measured shaft, the bridge is also in an unbalanced condition, resulting in an initial output voltage U0. The data processing module eliminates this initial value, making the output voltage proportional to the strain generated by the load torque. After the tractor begins operating, the speed sensor collects the speed signal, and the measurement module collects the electrical and temperature signals. A connection is established with the data processing module via GPRS to collect relevant tractor operating data. The data processing module processes the signals and compares them with the calibrated values ​​from the preliminary test to eliminate temperature errors. Load torque data is then obtained and displayed via cloud service platform software on an industrial computer. Workers can download the data from the cloud service platform software to mobile devices such as computers, tablets, and mobile phones via 4G / 5G / Wi-Fi signals.

[0046] The load torque measuring device for a tractor provided in this embodiment has a simple structure and is easy to use. It overcomes the shortcomings of existing torque sensor signal hysteresis, the traditional strain-type torque measurement method being limited by factors such as humidity, temperature, and adhesives, and poor anti-interference ability. It has the function of real-time measurement of the load torque of the tractor under actual working conditions, has low alignment requirements, and high measurement accuracy.

[0047] The above are merely preferred embodiments of the present invention to facilitate a full understanding of the present invention. It should be noted that the present invention is not limited to the above embodiments. It is apparent to those skilled in the art that, without conflict, the technical features of the technical solution of the present invention may be added to or replaced, and such additions and replacements are also within the scope of the claims.

Claims

1. A load torque measuring device for a tractor, comprising a rotation speed sensor (1), a connecting device (2), a measuring module (3), and a data processing module (4); characterized in that: The tractor load torque measuring device is connected in series between the tractor power output shaft universal coupling and the agricultural implement transmission shaft via a connecting device (2); wherein: The speed sensor (1) is a unipolar Hall sensor, comprising a signal disk (101), a sensor (102), and a loading device (103). The signal disk (101) is fixed on a measuring shaft (203). The sensor (102) detects a changing magnetic field signal generated by the rotation of the signal disk (101), outputs a speed pulse signal representing the speed of the universal joint, and transmits the signal via GPRS to perform data interaction with a data processing module (4). The speed measurement method is specifically as follows: The detection signal disk (101) is provided with a plurality of magnetic marks, and when the power output shaft rotates, the magnetic marks are driven to rotate; The sensor (102) detects a magnetic signal generated by the rotation of the magnetic marker and outputs a jump signal. The frequency of the jump signal can represent the rotation speed, and the frequency of the jump signal is averaged. The loading device (103) satisfies the bench test and is directly arranged on the test bench or a rack connected to the bench. The speed parameter is input through the industrial computer interface, and the loading device (103) controls the loaded torque (N·m), thereby controlling the speed; The connecting device (2) comprises a flange (201), a universal joint shaft assembly (202) and a measuring shaft (203); The measuring module (3) comprises a measuring chamber (301), a measuring circuit (302) and a temperature sensor (303), wherein the measuring chamber (301) is composed of two rotating rings that rotate synchronously with the shaft, the rotating rings are fixed to the middle section of the measuring shaft (203) by a key connection, and the rotating rings are engaged by a 45° toothed structure at the edge, and a resistance strain gauge is attached to the rotating rings to form a bridge circuit, the output end of the bridge circuit is connected to a signal amplification circuit, and the signal is sent to the data processing module (4) via GPRS, and is received and processed by the data processing module (4); The torque measurement method is as follows: An AC unbalanced bridge is selected to measure dynamic torque parameters. The first bridge arm is connected to a resistance strain gauge, and the other three bridge arms are connected to fixed resistors. Since the center line of the initial meshing point between the rotating rings is not strictly perpendicular to the axial direction of the measured shaft, when the measured shaft rotates at a speed n and no torque occurs, the bridge is also in an unbalanced condition, and there is an initial output voltage U0. When the measured shaft is twisted, the meshing point between the rotating rings deviates from the initial position and moves to the next position. The voltage value becomes U and is transmitted to the industrial computer for analysis and processing. The torque of the measured shaft is proportional to the torque acting on the measured shaft. The torque signal acting on the measured shaft is measured by measuring the voltage values ​​U0 and U. The amplified output voltage and the standard torque value are calibrated. In the formal experiment, the load torque is obtained by querying the calibration table. A signal amplification circuit including an AC amplifier is selected to amplify the weak output signal inside the sensor, multiple sets of identical strain measurement circuits are set on the teeth of the measurement cabin (301), and the data processing module (4) calculates the average value of the multiple sets of output electrical signals; The data processing module (4) includes an industrial computer (401) and a cloud service platform (402), wherein the cloud service platform (402) processes the electrical signals transmitted by the speed sensor (1) and the measurement module (3) to obtain the speed of the tractor engine output shaft, the temperature of the universal joint, and the loading torque of the loading device (103) in the bench test. The speed and torque data are monitored and modified in real time through the cloud service platform software, and the torque data is revised according to the temperature data to eliminate the temperature effect. The voltage and standard torque value output after amplification are calibrated. During the formal experiment, the torque can be queried and obtained according to the calibration table. The tester downloads and saves the torque data to a mobile phone, computer, or tablet computer on the cloud service platform (402) through a 4G / 5G / WIFI signal.

2. The load torque measuring device for a tractor according to claim 1, wherein: The universal transmission shaft assembly (202) adopts a ball cage elastic coupling to reduce the torsional vibration amplitude and the impact caused by dynamic loads, prevent the occurrence of additional resistance and additional mechanical vibration, and improve the stability of output power.

3. The load torque measuring device for a tractor according to claim 1, wherein: The distance S between the measuring chambers (301) is determined according to actual conditions.

4. The load torque measuring device for a tractor according to claim 1, wherein: The temperature sensor (303) in the measuring module (3) is arranged on the measuring shaft (203). The temperature sensor (303) collects an electrical signal and transmits it to the data processing module (4) via GPRS. The industrial computer (401) integrates and calibrates the electrical signal data representing the temperature to obtain the relationship between voltage and temperature. In the formal measurement, the industrial computer (401) corrects the torque signal according to the signal transmitted by the temperature sensor (303), thereby eliminating the influence of temperature on the torque measurement.

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