How to Test Electric Cylinders According to ISO 16750-3 (Road Vehicles - Environmental Conditions and Tests - Mechanical Loads)
I. Pre-Test Preparation: Accurately Define Test Parameters
Key Parameters Based on the Standard
Special Requirements for Electric Cylinders
Installation Location ISO 16750-1 Vehicle Partitioning: Steering System/Chassis Suspension Vibration Spectra Differentiate
Vibration Spectrum Selection Appendix B (Random)/C (Sinusoidal): Steering Cylinders are Preferred
Appendix B Random Vibration (Simulating Mixed Road Surfaces)
Axial Test: Clause 4.1: Piston Rod Movement Direction (Z-Axis) Must Be Tested, X/Y Axis Included
Temperature Coupling: Company Standard: Cylinders with Built-in Motors Must Be Tested -40°C to 125°C
✅ Pothole avoidance: The piston rod must simulate actual load (e.g., connect a 500N spring to simulate steering resistance).
II. Test Execution Process (Using the Steering System Electric Cylinder as an Example)
Step 1: Sine Sweep Vibration (Locate Resonance Point)
Standard: Appendix C
Parameters:
Frequency: 5Hz → 200Hz → 5Hz
Amplitude: ±1.5mm (5-25Hz) / ±2g (25-200Hz)
Sweep Rate: 1 octave/min
Monitoring Key Points:
�� Abnormal noise from motor bearings (microphone capture)
�� Data jumps from the piston rod displacement sensor
Step 2: Random Vibration (Simulates Real Road Conditions)
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graph LR
A [Electric Cylinder Installed on Steering Gear] --> B {Select Road Spectrum}
B --> | Urban Road | C [PSD: 0.01g²/Hz@5-50Hz]
B --> | Off-Road | D [PSD: 0.04g²/Hz @ 10-300Hz]
C & D --> E [Test duration ≥ 24 hours]
Step 3: Mechanical Shock (Simulating Collision/Bumping)
Working Condition: Half-sine Wave
Parameters:
Direction Peak Acceleration Pulse Width Count
Z-axis 50g 11ms 3 times
X/Y-axis 30g 6ms 3 times
Failure Judgment: Piston rod seal leakage > 0.1ml/h after impact → Failure
III. Specific Monitoring Items for Electric Cylinders (Critical Items Missed by 90% of Companies)
Dynamic Accuracy Monitoring
Laser displacement sensor monitors piston rod position in real time (position deviation > ±0.05mm during vibration indicates failure)
Motor Current Fluctuation Analysis
Current Fluctuation during Vibration > 15% of Rated Value → Exposure to bearing damage risk
Seal pressure test
After vibration, maintain pressure at 5 MPa oil pressure for 10 minutes, leakage < 3 drops/min
IV. Typical Failure Cases and Countermeasures
Failure Phenomenon
Root Cause
Improvement Plan
Loose piston rod threads
Resonance frequency not avoided (around 80 Hz)
Increase local stiffness/glue lock
Position sensor signal interruption
Connector loosening due to vibration
Replace with Hirose MX34 series anti-vibration connector
Motor magnet detached
Epoxy adhesive insufficient vibration resistance
Replace with 3M DP460 vibration-resistant structural adhesive
V. Four core electric cylinder data items required in the test report
Resonance frequency distribution diagram (marked with design avoidance range)
Piston rod displacement drift curve (entire vibration process)
Temperature rise record (motor winding temperature ≤ 150°C)
Before and after seal test comparison (helium mass spectrometer leak rate data)
VI. Cost Reduction and Efficiency Improvement Plan
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# Test Time Compression Algorithm (Based on Damage Equivalence Model)
Acquire actual road spectra → Generate PSD spectra → Calculate Grms values → Scale up using Miner's law
→ Compress a 200-hour road test into a 24-hour bench test (requires third-party certification of equivalence)
VII. Recommended Collaboration Process
Provide parameters → Cylinder installation diagram/load curve/operating temperature range
Laboratory matching → Select a facility with dedicated servo cylinder fixtures (such as Luxshare Testing)
Test execution → Simultaneously monitor motor hot spots with an infrared thermal imaging camera
Corrective action support → Obtain a failure analysis report (including FTA fault tree)
