Leaf springs (also known as steel leaf springs) are elastic components made up of multiple layers of alloy spring steel of varying lengths, widely used in automotive suspension systems. They have characteristics such as strong load-bearing capacity, simple structure, and low cost.

High-quality leaf springs can ensure the stability and handling of the vehicle, avoiding issues such as fractures and strange sounds due to material fatigue or structural failure, thereby reducing the risk of losing control. and high-quality leaf springs can effectively filter road vibrations, reduce the feeling of bumps, and enhance the riding comfort.

UnitedTest provides a fatigue testing system suitable for both static and dynamic testing of leaf springs. These testing machines feature an optimized load frame design, appropriate hydraulic attachments for optimal control precision, user-friendly application software, and accessories that integrate seamlessly with leaf spring testing. These servo-hydraulic fatigue testing machines can provide suitable load capacity, drive stroke, and table size according to our leaf spring quality control and R&D needs. We offer different attachments that can interface with various types of leaf springs, including eye and eyelet, round-end, hook-end, flat-end, etc., to meet your specific leaf spring requirements. The testing system can be expanded with attachments to meet the needs of various other material testing applications.

Main specifciation: 

1, Max. static test load: ±300kN, full range stepless, 2%~100% range, accuracy ±1%. 

2, Max. dynamic test load: ±300kN, fluctuation less than±2%FS. 

3, Actuator stroke: 0-200mm, indication accuracy ±1%.

4, Frequency range: 0.01—25Hz. (at max. frequency 25HZ, the multiple is ±2mm)

5, Max. speed: 21Mpa, 45L/min. 

6, Controller type: Single channel; displacement and load close-loop dual channels. 

7, Main test waveform: Sine wave, triangular wave, rectangle wave, oblique wave etc.,;

8, Test space: 

Max. adjusting net height space 500mm, width 500mm 

9, Frame stiffness: 3.3×108 N/m. 

10, Round specimen clamping range: Round sample 9mm-15mm, 15mm-22mm

11, Sample clamping length: 150mm

12, Displacement measuring resolution: 0.002mm

13, Counter: 999,999,999, can free set.

Main function: 

Material and components fatigue test

1, Fatigue working life study;

2, Cracking extension and breaking load study;

3, Tensile, compression, bending test

4, Components and parts fatigue and life working test.

Main Structures:

1, Mainframe

Mainframe is four column with crosshead and base frame structure, surface electroplating hard chromium, servo liner actuator installed at upside of frame.  Main function of frame is clamping the specimen, and according program instruction to finish the sample loading process.

1.1, Four column frame structure, hydraulic oil cylinder control crosshead lift, hydraulic cylinder control specimen clamping; easy adjusting and operation. Specific oil system can ensure test process accuracy and reliable, and it can keep crosshead locked unmovable at non-test condition.

1.2, With high stiffness and strength crosshead.

1.3, Crosshead moving, cylinder lock etc., sealing components adopts imported brand part, ensure the reliability and excellence performance.

1.4, Column surface is processed by electroplating hard chromium, improve the anti-corrosion ability and appearance.

1.5, Crosshead lift driving module adopts high quality integrated hydraulic components; console structure is designed according theory of man-machine engineering, convenient for operator using.

2, Actuator

The servo linear actuator is the core component of the testing machine, and the testing machine outputs the test force through the actuator. The actuator is built in the lower part of the main engine and is composed of the actuator body, hydraulic control module and sensor.

2.1. The actuator uses a servo linear actuator and is designed based on the principle of symmetrical four-way servo valve controlled symmetrical actuator. The actuator is designed and manufactured with the concept of unitization, modularization and standardization, and adopts a multi-level flexible support combined guiding mechanism, which has the characteristics of low damping, high response, high life and large gap design. Zero starting pressure, no crawling.

2.2. The actuator piston seal adopts clearance sealing mode, which is supported by imported sealing ring, large clearance design, high resistance to lateral force, and has the characteristics of high-speed non sintering and self-lubricating. The combined seal, high-pressure seal, low-pressure seal and clearance leakage pipe and actuator assembly shall be free of oil leakage. The above sealing methods can effectively reduce the internal friction resistance of the actuator, improve the testing accuracy of the testing machine and the service life of the actuator. The frequency response of servo linear actuator shall not be less than 100Hz.

2.3 hydraulic buffer zone shall be designed at the amplitude limit position of servo linear actuator to avoid damage caused by out of control operation.

2.4. The displacement sensor of servo linear actuator is flexible and free from external interference. The piston rod is ultra precision machined, and the surface is coated and polished to R α 0.4u.

2.5. The actuator is externally installed with a hydraulic module consisting of a precision oil filter with a filtering accuracy of 0.003mm and a two-stage electro-hydraulic servo valve dedicated to the dynamic testing machine of the accumulator in the inlet and return oil circuit with pulse elimination and energy storage functions. The precision oil filter is installed in front of the electro-hydraulic servo valve, which can effectively prevent the electro-hydraulic servo valve from blocking due to hydraulic oil pollution.

2.6, a special clearance elimination device is designed at the connecting screw between the load sensor and the hydraulic collet, and at the piston rod and the hydraulic collet to further improve the dynamic response performance

3, Control software

Control module: can achieve closed-loop control function, can arbitrarily capture signals for full digital closed-loop control, closed-loop control frequency 10kHz;

Servo valve drive unit: nozzle servo valve drive control;

The frequency range of the waveform generator: 0.001-30Hz, frequency resolution: 0.001Hz;

Control waveforms: sine waves, triangular waves, square waves, serrated waves, semi-sine waves, semi-triangular waves, random waves, and external input waveforms;

Control mode: force, displacement and deformation closed-loop control, can achieve smooth switching of any control mode;

The system has sensor calibration and zeroing functions;

Perfect hydraulic station monitoring function, can monitor oil temperature, pressure, etc.

brand computer, mainstream configuration

HP laser printer.