Organize AGV tire tread groove design from the perspectives of size and drive configuration, and examine its relationship with initial slip at start-up.
AGV Tread Groove Design and Drive Configuration
2026-02-26
Premise
Initial slip at start-up is a phenomenon in which the surface slides before static friction fully develops.
Governing factors
• μ
• Drive wheel load N
• Starting torque
• Contact length
Tread grooves are a factor that modifies μ.
Drive configuration is a factor that determines N.
These must be considered separately.
Design by Size
Small diameter (φ100–150)
• Short contact length
• Edge count tends to be insufficient
→ Fine pitch (2–3 mm)
→ Depth 0.3–0.6 mm
Medium diameter (φ150–300)
• High design flexibility
→ Pitch 3–5 mm
→ Depth 0.5–0.8 mm
→ Combination of lateral and diagonal grooves
Large diameter (φ300 and above)
• Long shear distance
• Attention to block deformation
→ Pitch 4–8 mm
→ Depth within 0.5–1.0 mm
Groove depth should remain within 10–20% of tread thickness.
Drive Wheels
4-wheel Front-Wheel Drive
Front wheel load decreases during acceleration.
High slip risk.
Drive wheels
• Lateral-groove based pattern
• Pitch 2–4 mm
• Even shallow grooves require high edge density
Non-drive wheels
• Wear prioritized
• Shallow grooves acceptable
FWD is a configuration with high dependence on groove design.
4-wheel Rear-Wheel Drive
Rear wheel load increases during acceleration.
Start-up tends to be stable.
Drive wheels
• Pitch 3–5 mm
• Lateral plus mild diagonal
Excessively fine grooves are unnecessary.
6-wheel Center Two-Wheel Drive
Load is distributed at rest.
Only the center wheels are driven.
Center wheels may lift on uneven floors.
This configuration is most prone to slip.
Center wheels
• Reinforced lateral grooves
• Pitch 2–4 mm
• Depth 0.5–0.8 mm
• Ensure sufficient edge count
Front and rear wheels
• Shallow grooves
• Wear prioritized
For center drive, groove design alone is often insufficient.
Constraints of PU Material
• Deep grooves are prone to chipping
• Sharp V-shaped bottoms become crack initiation points
• Block widths below 3 mm are unstable
It is safer to increase groove density rather than groove depth.
Summary
Slip limit
Maximum driving force = μ × N
Grooves modify μ.
Drive configuration determines N.
Small diameter + front-wheel drive + center drive
This combination shows high dependence on groove design.
Large diameter + rear-wheel drive
Groove influence is relatively smaller.
Groove design must be redefined according to the combination of size and drive configuration.