Electromechanical cylinders, as core actuators in critical vehicle systems like steering, suspension, and
braking, undergo ISO 16750-3 testing, a mandatory requirement for ensuring vehicle safety and reliabili
ty. The following is an in-depth analysis of their necessity:
1. Unique Risks of Electric Cylinders: Why is ISO 16750-3 Testing Essential?
Failure Modes Direct Consequences Cascading Risks
Loose piston rod threads Sudden loss of power steering Loss of vehicle control → Fatal accident
Motor bearing vibration and cracking Seized electric cylinder with no return Braking system/steering
lock
Position sensor offset System misjudgment of piston position Incorrect active suspension movement →
Vehicle rollover
High-frequency seal wear Hydraulic fluid leakage → Circuit contamination Short circuit fire (high risk for
new energy vehicles)
II. Four Core Issues Addressed by ISO 16750-3 Testing
1. Quantifying Mechanical Impact in Extreme Road Conditions
Simulation Scenario:
30cm deep pothole impact (50g/11ms half-sine wave)
Belgian gravel road (20-300Hz random vibration)
Electric cylinder pain point: Resonance amplification effect in piston rod reciprocating motion
2. Exposing design flaws
3. Meeting regulatory requirements
EU e-mark certification: ECE R79 (steering system) mandatory ISO 16750-3 certification 16750-3
China's mandatory standard: GB/T 18655-2018 requires steering cylinders to pass mechanical load tests.
Automakers' threshold: Tesla, NIO, and others require electric cylinders to undergo additional "loaded
vibration testing" (dynamic force applied to the piston rod).
4. Reducing Lifecycle Costs
III. Three Unique Challenges of Electric Cylinder Testing
Dynamic Accuracy Failure
Standard Requirement: Piston rod displacement error during vibration ≤±0.1mm
Measurement Solution: Real-time monitoring with a laser interferometer (non-standard installation)
Electromechanical Coupling Interference
Motor electromagnetic field vibration → Interference with position sensor signals
Countermeasure: Simultaneously monitor the Hall effect signal-to-noise ratio (SNR > 20dB) during
testing
Temperature Rise Accelerates Aging
Combined Test: Vibration + 125°C High Temperature → Verify the risk of seal thermal expansion
failure
IV. Industry-Leading Requirements: Exceeding Basic Standards
Test Items: ISO 16750-3 Requirements: Leading Automakers Stringently Require
Random Vibration Duration: 24 hours 50h (NIO ES8 standard)
Mechanical shock peak: 50g (Z-axis), 70g (Xpeng G9 battery pack area)
Temperature range: -40°C to 85°C, -40°C to 125°C (Tesla Cybertruck)
V. Practical Strategies for Efficiently Passing Inspections
1. Accurately Selecting a Test Spectrum
Steering Cylinder → Appendix B: Random Vibration + 50g Z-axis Shock
Air Suspension Cylinder → Add Appendix C: Sine Sweep (5-25Hz Resonance Range)
2. Accelerated Verification Solution
Cost Savings: Accelerated testing costs reduced by 40%
3. Closed-Loop Correction Process
Faults Revealed on a Vibration Table → Recorded with HD Industrial Video → Fault Tree Analysis (FTA) →
Retesting with Improved Design
