The dynamic fatigue testing machine for the central shaft is designed in accordance with the testing standards for the dynamic fatigue of the central shafts of bicycles and electric bikes. After the b ...
The dynamic fatigue testing machine for the central shaft is designed in accordance with the testing standards for the dynamic fatigue of the central shafts of bicycles and electric bikes. After the bicycle frame is fixed on the fixture of this testing machine, it is subjected to fatigue force with a certain frequency, load and test times. After the test, the damage degree of the sample is inspected to make a judgment. The position adjustment lock screws adopt quick-release type for easy operation, and the position adjustment is carried out by means of lead screws.
Technical parameters
| Parameter | Specification / Range |
|---|---|
| Capacity (kgf) | 500 kgf × 1 set |
| Load Cell Resolution | 1/10,000 |
| Displacement Sensor Range | 0–125 mm |
| Motor Control Frequency | 0–5 Hz |
| Force Control Accuracy | 5% |
| Power Source | Electric cylinder servo control system |
| Number of Electric Cylinders | Single |
| Software Interface | Derui Control System |
| Database Function | Automatically records each measurement result for easy analysis and evidence |
| Overall Dimensions | Test bench: 1700 × 1290 × 2100 mm (W×D×H) Control cabinet: 600 × 630 × 1850 mm (W×D×H) |
| Weight (approx.) | 160 kg |
| Power Supply | AC 220V, 15A |
| Computer Configuration | EVOC |
| Load Range | 500–5000 N (accuracy ±1%) |
| Loading Frequency | 0.5–5 Hz (adjustable) |
| Test Cycles | 100,000 – 2,000,000 cycles (customizable) |
| Adjustable Stroke | 0–300 mm (three‑way adjustment, accuracy ±0.1 mm) |
| Data Sampling | 100 Hz (synchronously acquires load, strain, etc.) |
| Compatible Bike Models | 20–29 inch bicycles (bottom bracket length 110–135 mm) |
Dynamic fatigue loading
Simulating the force on the bottom bracket during real cycling. The equipment uses a servo hydraulic/electric loading system (optional), and through the "fixture - frame - bottom bracket" linkage structure, it applies "periodic dynamic loads" to the bottom bracket, fully reproducing the "pedaling torque, bumping bending moment, lateral shear force" and other composite stresses during cycling:
1.Precise control of load parameters:
Load range: 500 - 5000N (covering scenarios from "light pedaling by a single person" to "competitive-level explosive pedaling"), with an accuracy of ±1%;
Loading frequency: 0.5 - 5Hz (adjustable), simulating different rhythms such as "commuting at a constant speed (1Hz)" and "climbing sprints (3Hz)";
Test cycles: 100,000 - 2,000,000 times (customizable), meeting the core requirement of ISO 4210-6.5 for "no cracks after 1,000,000 cycles" (traditional equipment only supports fixed cycles and cannot meet the demands of extreme testing during R&D).
2.Multi-directional stress composite loading:
Supports dual-axis loading of "vertical load + horizontal torque" (such as the bottom bracket being subjected to vertical pressure during pedaling, and horizontal torque due to crank swing);
Can set "sine wave/square wave/random wave" load waveforms (simulating "continuous bumps" and "emergency braking impacts" and other irregular forces), providing more comprehensive testing coverage (traditional equipment only supports single-axis and single-direction loading, missing composite stress damage).
Applicable Standards
1.Bicycle Standards:
ISO 4210-8: Bicycles - Safety requirements (Part 8: Test methods for pedals and drive systems) - This standard includes the dynamic fatigue test method for bottom bracket assemblies.
GB 3565: Safety Requirements for Bicycles (Chinese National Standard, corresponding to ISO 4210).
2.Electric bicycle standards:
GB 17761-2024: Safety Technical Specification for Electric Bicycles (Referring to the requirements for the bottom bracket in relevant standards for bicycles).
EN 15194: European standard for electrically assisted bicycles. Special note: In mid-drive models, the bottom bracket not only has to bear the force from human pedaling but also the torque from the motor assistance. The test load is usually significantly higher than that of ordinary bicycles.
Main components:
1. Mechanical host:
Rigid frame: It supports the actuator and the specimen and must have extremely high rigidity to prevent its own deformation from affecting the test accuracy.
Simulated bottom bracket fixture: A replaceable, high-precision fixture for simulating different specifications of bottom brackets (such as English 68/73mm, BSA, BB30, BB86, BB90, T47, etc.).
Loading arm: It is used to connect the actuator with the end of the central shaft, simulating the length of the crank and the point of force application.
2. Drive and loading system:
Servo actuator: Usually there are two (one on each side), used to apply alternating loads. It can be electro-hydraulic servo (for large tonnage) or electric servo (for high frequency and precision).
Rotary drive (optional): If a simulated rotation is required, a small motor can be added to drive the central axis to rotate.
3. Measurement and Control System:
Industrial computer and software: Set test parameters (load, frequency, number of cycles, waveform), monitor test progress, and record data.
Controller: Achieves closed-loop control (force control or displacement control).
4. Sensor System:
Force sensor: Monitors the actual load applied by each actuator.
Displacement sensor: Monitors the bending deformation of the shaft or the change in bearing clearance.
Temperature sensor (optional): Monitors the temperature rise of the bearing during operation.
Vibration sensor (optional): For early detection of bearing damage.
