In AGV (Automated Guided Vehicle) mobility systems, castor/idler wheels act as the vehicle’s “silent legs.” Though non-driven, they are critical for stable movement—supporting chassis weight, absorbing ground shocks, and ensuring drive wheel traction. Poor selection causes body sway, abnormal wear, or wheel slippage. Scientific selection is key to building highly reliable AGV chassis.
Castor Wheels: Silent Guardians of Stability
Designed for 360° steering via horizontal rotation and ball bearings, castor wheels fulfill three core functions:
Load Distribution & Anti-Tip: Prevent drive wheel lift-off under heavy loads.
Shock Absorption: Dampen vibrations from rail seams or uneven surfaces.
Dynamic Correction: Assist steer drives in real-time path tracking.
Polyurethane Wheels: The Industrial AGV Standard
Polyurethane outperforms alternatives with:
Exceptional Wear Resistance (20,000+ hours service life).
Oil/Chemical Resistance (withstands grease/solvents).
Quiet Operation (<65 dB noise).
Nylon wheels shed debris; rubber wheels crack prematurely.
Four Core Dimensions for Scientific Selection
1.Load Capacity: The Safety Baseline
Per-Wheel Load = (AGV Weight + Max Payload) × Safety Factor (1.2–1.5) ÷ Number of Wheels
Example: 1-ton AGV + 500kg payload with 4 wheels → Min. 487.5kg/wheel.
Impact Margin: Add 20% capacity for frequent start-stop cycles.
2.Wheel Diameter & Tread Width: Scenario Adaptation
Smooth Floors (Warehouses/Electronics):
Ø75–100mm narrow wheels (30–40mm width) minimize rolling resistance.
Rough Terrain (Construction/Foundries):
Ø125–150mm wide-tread wheels (50–60mm width) enhance obstacle clearance.
Cold Storage (–30°C):
Ø100mm+ wide-tread wheels maximize grip via larger contact area.
3.Bearing Structure: Determines Steering Lifespan
Double-Row Ball Bearings:
40% higher load capacity, superior lateral impact resistance—essential for heavy AGVs.
Single-Row Ball Bearings:
Lower steering resistance—suits light, high-speed AGVs.
4.Extreme Environment Solutions
Food/Pharma: FDA-compliant blue polyurethane wheels + stainless steel cores.
High-Temperature Workshops: Flame-retardant polyurethane (120°C-rated) + metal dust covers.
ESD-Sensitive Areas: Conductive wheels (surface resistance: 10^6–10^9 Ω).
Real Costs of Selection Errors
Case 1: Undersized Wheels Cause Drive Slippage
Fault: 1.2-ton AGV in auto plant used Ø80mm narrow wheels—oil slicks caused drive wheel lift-off.
Solution: Upgraded to Ø125mm wide-tread wheels → zero failures.
Case 2: Bearing Seal Failure Halts Production
Fault: AGV in ceramic plant failed 5×/month—dust ingress into unsealed bearings.
Solution: Triple labyrinth-sealed bearings → 3× lifespan extension.
Case 3: Cold-Induced Cracking Paralyzes Logistics
Fault: Standard polyurethane wheels brittle fractured at –25°C.
Solution: Switched to –40°C cold-resistant formula → stable operation.
