1、 Scheme description:

The NZP4000 electro-hydraulic servo torsion fatigue testing machine mainly consists of a main unit (including servo pendulum actuator), a constant pressure servo pump station 11.112 (110L/min), a relay energy storage filter module, a fully digital single channel servo controller DTC-200s, supporting test software, and other accessories. The schematic diagram of the system control principle is shown in the figure.
Equipment usage environment requirements:
a) Under the conditions of room temperature of 5-45 ℃ and relative humidity not exceeding 90%;
b) Install horizontally in a stable foundation and vibration free environment;
c) There is no corrosive medium around;
d) In an environment without significant electromagnetic interference;
e) The fluctuation range of power supply voltage shall not exceed ± 10% of the rated value;
f) Power supply 380V, 50Hz; 220V，50Hz；
g) Configure a cooling circulating water device with a flow rate of not less than 200L/min and a pressure of 0.3Mpa;
h) For the convenience of experimental operation and maintenance, there should be a certain amount of space around the testing machine.
1. Host: The host is a horizontal structure, and the servo pendulum actuator is installed at one end of the host. The appearance photos are shown in Figure 3, and Figure 4 is the on-site photos taken by the user.
1.1. The host is a horizontal structure of the machine tool, which is easy to operate. Ensure sufficient mechanical strength and rigidity.
1.2. The two sides of the servo pendulum actuator are installed on one end of the platform with multiple layers of elastic steel plates stacked together. The output end of the servo pendulum actuator is equipped with an unloading bearing seat to jointly protect the servo pendulum actuator from damage caused by axial force.
1.3. The two sides of the tailstock are also installed on one end of the platform through multiple layers of elastic steel plates stacked together. The spring steel plates are installed on a rotating flat plate with adjustable angles (which can be used for torsional fatigue testing of automotive half axis CV joints at different angles), and the rotating flat plate is installed on a sliding flat plate. The sliding flat plate is installed on the T-shaped groove on the main platform and can move along the T-shaped groove to adjust the test space to accommodate different sizes of specimens. After the adjustment of the test space is completed, the tailstock is rigidly fixed to the main platform using T-shaped bolts.
1.4. Install torque sensors on the tailstock, and equip the torque sensors with products from the domestic Aerospace 701 Research Institute (or similar products from Changsha Xiangyi Company).
1.5. The end of the servo pendulum actuator is equipped with an angle sensor through an elastic coupling.
1.6. The output end of the swing actuator and the input end of the torque sensor are both connected to the tested piece through flanges. By replacing the connecting flanges, they can be applied to different types and specifications of specimens.
2. Servo pendulum actuator 22.503: A new type of servo pendulum actuator designed and manufactured with a completely new concept.
2.1. The servo swing actuator with modular, standardized, and modular design features low damping, high response, long lifespan, and large clearance design. The design concept is completely equivalent to MTS Series 215&216 Rotary Actors.
2.2. The sealing element of the servo pendulum actuator adopts imported high-speed sealing elements specifically designed for German servo actuators.
2.3. The support of the servo pendulum actuator piston rod breaks the traditional design, adopts non-metallic support and large clearance design, and has the characteristics of high-speed non sintering self-lubricating.
2.4. The amplitude limit position of the servo pendulum actuator is designed with a hydraulic buffer zone to avoid damage caused by uncontrolled operation.
2.5. The output end of the servo pendulum actuator is equipped with an unloading bearing seat, which can resist the axial force generated when the specimen deforms. The servo pendulum actuator is flexibly connected to the frame, and multiple layers of elastic steel plates are used on both sides for elastic support to avoid damage to the servo pendulum actuator from axial deformation of the specimen during the test.
2.6. Install a dedicated servo valve for domestic high response testing machines (with a flow rate of 95L/min at 7Mpa).
2.7. Install an angle sensor to measure the rotation angle of the actuator.
2.8. The shaft and transition coupling plate adopt a unique connection method to further improve the dynamic response performance.
2.9. It has two closed-loop control circuits for torque and angle.
3. Constant pressure servo pump station 11.112: The pump station is mainly composed of a base plate, oil tank, oil pump motor group, valve block, pipeline, cooling system and other parts. Used to provide power for the operation of the testing machine.
3.1. The pump station oil tank adopts a fully enclosed design, which can effectively prevent external impurities from entering the hydraulic system and contaminating the hydraulic oil. The inner wall of the fuel tank material is treated with special technology, which can effectively prevent metal corrosion from contaminating the hydraulic oil.
3.2. The configuration of the oil pump and motor unit adopts a series double elastic support method to further reduce the noise of the pump station.
3.3. The oil pump adopts a low-noise linear conjugate internal gear pump. Characteristics of the straight line internal meshing gear pump: It is known as the "never worn oil pump" in the hydraulic industry and is used in high precision, pointed hydraulic systems. Several well-known international companies have developed and promoted it as a branded product to ensure their leading position in the hydraulic industry. Compared with vane pumps and plunger pumps, linear co axial internal meshing gear pumps have excellent performance such as low noise, no pulsation, and long service life. Low noise: The excellent feature of the linear internal meshing gear pump is its special gear design, with a straight gear tooth profile and a linear ring gear profile. There is almost no oil trap during operation, and even at high speeds, the audio is still smooth and flat. Longevity: The long-life characteristics of the linear internal meshing gear pump depend on wear resistance. There is an oil film protective layer between the internal mechanical surface and various functional parts, which has almost no wear and tear. Even if general hydraulic oil is used, the parts are not easily worn. In addition, the principle of dual stage pressurization to bear the pressure difference is adopted, which not only increases the working pressure, but also improves the working conditions of the pump and extends its service life;
3.4. The high and low pressure soft switching hydraulic module composed of the main overflow valve, accumulator, auxiliary main overflow valve, auxiliary overflow valve and directional valve, and precision oil filter is used to control the output pressure of the pump station;
3.5. The pump station has a working mode of low pressure starting and high pressure switching, which can effectively reduce the impact of the hydraulic system. It also has a safety protection valve to prevent damage to the hydraulic system caused by misoperation;
3.6. The pump station is equipped with an inline water cooler (to be provided by the user) for cooling the hydraulic system;
3.7. The pump station is equipped with a dual electric contact temperature control meter and a liquid level control meter; Equipped with oil temperature (below 10 º C, above 55 º C), liquid level, filter blockage alarm, and parking protection functions
3.8. The fluid connections of the pump station are equipped with hydraulic fittings and high-pressure hoses from Parker PARKER in the United States to ensure that the system is leak free;

Figure 5: Photo of Constant Voltage Servo Pump Station
4. Relay energy storage oil filtration module: The module is equipped with a precision oil filter with a filtration accuracy of 0.003mm (imported from Germany's H ä ldek technology) and an inlet and outlet oil accumulator (Sino British joint venture Fenghua Orel). The module is installed on the swing actuator side of the host to eliminate the pulsation generated during system operation and provide high-precision filtration for the servo valve inlet oil to protect the servo valve from pollution.
5. Full digital single channel servo controller DTC-200s main technical indicators:
5.1 Number of control channels: 1, each channel includes two closed-loop control loops for test torque and angle, with control mode smooth switching function without disturbance.
5.2 The maximum closed-loop control data refresh frequency is 6kHz;
5.3 The A/D and D/A resolutions of the controller are 16 bits;
5.4 Signal frequency range: 0.01Hz to 25Hz;
5.5 Signal generator waveforms: sine wave, triangular wave, square wave, sawtooth wave, random wave;
5.6 Control accuracy: The typical value of static control accuracy is generally 0.5% FS, and the typical value of dynamic control accuracy is generally 0.5% FS;
5.7 Two stage servo valve drive unit;
5.8 Remote hydraulic pump station control function;
5.9 Counter capacity: 108;
5.10 Other necessary I/O input/output units: four analog inputs, four analog output interfaces; Four digital input and four digital output interfaces (optional);
5.11 has functions such as overload protection, sample fracture protection, limit parameter setting, and test frequency setting;
Control software PowerTestV3.0-J for 6 electro-hydraulic servo dynamic testing machine (system)
System management software PowerTestV3.0-J01C: This software is the foundation of the entire digital servo controller. Its main functions include managing the hardware resources of the control system, defining sensors, adjusting digital control parameters, setting protection, displaying the current control mode, hydraulic and function generator status, and sensor calibration. It also provides a dual track digital oscilloscope, digital servo valve ammeter, and 6 digital voltmeters for real-time display of test data. Figure 7 is the main interface diagram of the single channel test assistant system management software, and Figure 8 is the main interface diagram of the dual channel test assistant system management software. Figure 9 is the oscilloscope interface diagram, and Figure 10 is the digital voltmeter interface diagram.
6.1. The software usage environment is Windows XP, with a Chinese operating interface;
6.2. Users can easily set various test functions and parameters from the operation interface, such as customizing system parameters, setting test frequency, torsion direction, high/low load, cycle times, etc.
6.3. The software is equipped with real-time graphical display and editing functions, which automatically collect, record and display various test curves in real time;
6.4. The software has functions such as fault limit setting, automatic fault diagnosis, and zero drift correction;
Function generator software PowerTestV3.0-J02C: This software is mainly used for constant amplitude dynamic testing, such as constant amplitude fatigue testing, constant amplitude fatigue crack propagation testing, etc. The function generator software will automatically track and correct the peak to valley values of control variables (such as loads) to ensure that the typical dynamic error of each peak is ± 0.5% FS throughout the entire test process. During the test, the operator can dynamically change the peak, valley, and frequency, and can also manually or automatically maintain the signal. If the automatic signal maintenance cycle interval is set, the software will automatically maintain the signal at the set level for each additional cycle interval of the test cycle to facilitate the measurement of certain test data (such as visual crack length). The software offers waveform options including sine wave, triangular wave, and square wave. After the experiment is completed, the software will save some important data, such as test load, frequency, number of cycles, and test time. This software can also perform simple static operations

State test. Figure 11 is the main interface diagram of the function generator software.

Multi functional testing software PowerTestV3.0-J07C (similar to MTS 793.10MPT software in the United States): This software is a flexible and fully functional testing software that allows users to design special testing methods without programming. This software presents various control functions, data acquisition functions, and other auxiliary functions of the servo controller in the form of icons on a panel. Users can drag and drop these function icons to the experiment definition panel with the mouse, and freely combine them according to their needs to conduct experiments according to their custom testing methods. This software can be used for random spectrum experiments. The software has an open system architecture, which allows users to further expand the system;
7. Other configurations and necessary attachments:
7.1 All hydraulic fittings and high-pressure hoses are imported from Parker PARK, USA (standard configuration of 5-meter high-pressure hose from constant pressure servo pump station to relay energy storage oil filtration and separation module), to ensure that the entire system has no oil leakage and the testing environment is clean.
Design and manufacture a set of test connectors based on the test piece drawings provided by the equipment purchaser.
7.3 Configure flushing accessories for flushing pump stations and actuators to facilitate regular replacement of hydraulic oil for hydraulic system cleaning by users.
7.4 Configure the loading calibration device and hydraulic jack for calibrating the torque sensor, facilitating equipment acceptance and user's accuracy verification at any time.
7.5 Randomly give away five precision oil filter cartridges for free, making it easy for users to regularly replace hydraulic oil for hydraulic system cleaning.
8. Security protection function:
8.1. The system has various parameter alarm and protection functions;
8.2. The system has a sample damage protection function;
8.3. The system has hydraulic system temperature, liquid level, oil filter alarm, and protection functions;
8.4. For fault alarms, the computer can display diagnostic results and have corresponding sound and light alarm devices

2、 The main technical specifications of NZP4000 electro-hydraulic servo torsional fatigue testing machine are:
1. Maximum dynamic torque: ± 4000Nm, allowable maximum impact load not less than 25k N • m
2. Indication accuracy: Calibrate according to attenuation multiples of 1 and 10, with an indication accuracy of ± 0.5% for each level starting from 20%;
3. Accuracy of torque sensor reading: ± 0.2% FS;
4. Test frequency range: 0.01-15Hz;
5. Maximum test angle: ± 50 °;
6. Indication accuracy: ± 0.5%, resolution: 0.1 °;
7. Main test waveforms: sine wave, triangular wave, square wave, oblique wave or other external input waveforms;
8. The maximum experimental space is 1500mm;
9. It has two closed-loop control loops: angle and torque, which can switch smoothly and without disturbance;
10. Equipped with limit protection function for experimental parameters;
11. Specification of constant pressure servo pump station: flow rate of 110L/min, 21Mpa, motor power of 45kW;
12. Maximum angular velocity ± 300 °/s (4Hz, ± 12deg);
13. Counter capacity: 108.

3、 Other configurations and necessary accessories of NZP4000 electro-hydraulic servo torsion fatigue testing machine:
★ Configure calibration tools for calibrating sensors;
★ Configure flushing accessories for servo actuators and constant pressure servo pump stations;
All hydraulic fittings and high-pressure hoses are imported products to ensure that the entire system has no oil leakage;
★ Other necessary attachments.