Table of Contents
Note: This page summarizes a representative application example. Results are specific to the described design, validation scope, and production conditions.
Executive Summary
Client: E-bike hub motor manufacturer Challenge: Machined gears too expensive and noisy for mass-market e-bikes Solution: FN-0205 PM planetary gears with carburizing Results:
- 25% cost reduction
- Noise reduced 7 dB (72 dB to 65 dB)
- Transmission efficiency: 92% (vs 89% machined)
- 15,000 km service life (exceeds e-bike lifespan)
Customer Background
Industry: Electric bicycle manufacturing Application: 250W hub motor planetary gearbox (3:1 reduction) Volume: 500,000 e-bikes/year Market: Mid-range e-bikes ($800-1,500)
Original Design: Machined steel gears (4-gear planetary set)
The Challenge
Problem 1: Cost Pressure
- Issue: Machined gear set cost $6.50
- Target: <$5.00 to hit retail price point
- Impact: Losing market share to Chinese competitors
Problem 2: Noise Complaints
- Issue: Customer noise complaints (72 dB @ 25 km/h)
- Cause: Machined gear tooth profile variation (+/-0.05mm)
- Impact: 12% of customer reviews mentioned noise
Problem 3: Efficiency Loss
- Issue: Transmission efficiency only 89%
- Impact: 11% motor power lost to friction/heat
- Result: Reduced range by 2-3 km per charge
SinterWorks PM Solution
Material: FN-0205 (2% Ni, 5% Cu)
Why FN-0205?
- Good hardenability for case hardening
- Cost-effective (less nickel than FN-0408)
- Adequate strength for e-bike torque (40 Nm)
Manufacturing Process
- Precision Tooling: Gear tooth tooling (+/-0.02mm accuracy)
- Compaction: 650 MPa
- Sintering: 1120 deg C
- Sizing: Re-strike for +/-0.02mm tooth profile
- Carburizing: 900 deg C, 2 hours (case depth 0.5mm)
- Quench & Temper: Oil quench + 180 deg C temper
- Final Hardness: 58-60 HRC surface, 28-30 HRC core
Gear Specifications
- Sun Gear: 12 teeth (module 1.0)
- Planet Gears (3x): 18 teeth
- Ring Gear: 48 teeth (internal)
- Pressure Angle: 20°
- Accuracy Class: ISO 7 (after sizing)
Results
Noise Reduction
| Test Condition | Machined Gears | PM Gears | Improvement |
|---|---|---|---|
| 15 km/h | 68 dB | 62 dB | -6 dB |
| 25 km/h | 72 dB | 65 dB | -7 dB |
| 32 km/h (max) | 76 dB | 69 dB | -7 dB |
Reason: Tighter tooth profile tolerance (+/-0.02mm PM vs +/-0.05mm machined)
Efficiency Improvement
- Machined Gears: 89% transmission efficiency
- PM Gears: 92% transmission efficiency
- Impact: +3% range (1.5-2 km per charge)
Cost Comparison (Per Gear Set: 4 Gears)
| Element | Machined | PM | Savings |
|---|---|---|---|
| Material | $2.20 | $1.50 | 32% |
| Machining | $3.50 | $0.80 (minimal) | 77% |
| Heat Treatment | $0.80 | $1.20 | -50% |
| Total | $6.50 | $4.90 | 25% |
Annual Savings (500K e-bikes): $800,000
Field Performance
12-Month E-Bike Fleet Data (50,000 bikes)
- Noise Complaints: 2.5% (vs 12% baseline)
- Gear Failures: 0.08% (vs 0.3%)
- Average Distance: 15,000 km, no gear wear issues
- Customer Rating: 4.6/5 (up from 4.1/5)
Get PM Gears for E-Bikes
SinterWorks manufactures precision PM gears for e-mobility:
- Planetary, spur, and helical gears
- Case hardening in-house (carburizing, carbonitriding)
- Gear accuracy: ISO 6-7
- High-volume production (100K+ parts/year)
Related Resources
Use these internal links to keep moving through the most relevant guides, service pages, and technical references for this topic.
Electric Motor Components
See where PM fits motor structures, gears, and magnetic parts used across e-mobility and compact drive systems.
FN-0205 Material Guide
Review a versatile nickel-copper PM material route used for planetary gears and repeat-volume transmission hardware.
Powder Metallurgy Gears
Compare tooth quality direction, sizing logic, and production fit for PM gear programs before locking the route.
Request a Quote
Send your gear geometry, motor torque, and annual volume for PM gear review and quotation support.