Brass Motor Gear Fasteners：Brief Introduction

1. Definition of Brass Motor Gear Fasteners

 

• Dimensional precision: Thread accuracy (e.g., metric 6g/8g) and fitting clearance (≤0.02mm) to avoid gear misalignment;
• Working condition adaptability: Resistance to motor oil erosion, tolerance to 80-150℃ operating temperature, and anti-loosening under long-term vibration;
  Common types include brass gear bolts, set screws, and flange nuts, tailored to gear structure (e.g., helical gear, spur gear) and motor power.

2. Materials for Brass Motor Gear Fasteners

 

• H62 Brass (62% Cu): Moderate tensile strength (≥300MPa) and good impact resistance, suitable for low-to-medium power motors (e.g., 1-5kW household appliance motors);
• Hpb59-1 Brass (59% Cu, 1% Pb): Excellent machinability, easy to process high-precision threads (no burrs), ideal for fasteners with complex thread structures (e.g., double-ended gear bolts);
• H68 Brass (68% Cu): High ductility and fatigue resistance, able to withstand repeated torque impacts in high-speed motors (e.g., automotive starter motors, 8000+ RPM);
• Brass Alloys with Additives: For harsh environments (e.g., industrial motors with dust), add 0.5% Sn to enhance wear resistance, or 0.3% Si to improve oil resistance.

3. Functions of Brass Motor Gear Fasteners

 

1. Torque Transmission Support: Fix gears to rotating shafts, ensuring no slippage during torque transfer (e.g., preventing gear idling in automotive starter motors);
2. Precision Positioning: Maintain gear center distance and meshing clearance (≤0.05mm), avoiding noise or tooth wear caused by misalignment;
3. Vibration Damping: Brass’s inherent elasticity reduces vibration transmission between gears and housings, lowering motor operating noise (by 3-5dB compared to steel fasteners);
4. Environmental Adaptation: Resist corrosion from motor lubricating oil and ambient humidity, preventing rust-induced fastening failure (service life extended by 50% vs. carbon steel fasteners).

4. Processes for Brass Motor Gear Fasteners

 

1. Pretreatment:
   • Material cutting (cut brass rods into fixed lengths, error ≤0.1mm);
   • Ultrasonic degreasing (remove surface oil to avoid thread processing defects);
2. Forming Processes:
   • Cold Heading: For bolts/nuts, one-time forming of heads (high efficiency, 100-200 pieces/min, enhances material density);
   • Forging: For high-load fasteners (e.g., motor main gear bolts), hot forging to improve tensile strength (increase by 15-20%);
3. Finishing Processes:
   • Thread Processing: Roll threading (for external threads, precision up to 6g) or tapping (for internal threads, no thread breakage);
   • Heat Treatment: Low-temperature annealing (280-320℃) to eliminate processing stress, prevent thread deformation;
   • Surface Treatment: Electroplating (zinc/nickel, thickness 8-12μm) for anti-corrosion, or passivation to improve oil adhesion;
4. Inspection Processes:
   • Thread Gauge Testing (100% inspection of thread accuracy);
   • Torque Test (simulate motor working torque, check anti-loosening performance);
   • Salt Spray Test (48-hour test to verify corrosion resistance).

5. Machining of Brass Motor Gear Fasteners

 

• Cold Heading Automated Lines: For standard fasteners (e.g., M5-M12 gear bolts), integrate feeding, heading, and threading, daily output 50,000+ pieces, thread error ≤0.01mm;
• CNC Turning: For custom fasteners (e.g., non-standard head shapes), process complex structures (e.g., hexagonal heads with positioning holes) with dimensional accuracy ±0.005mm;
• Specialized Thread Machining:
  • Roll Threading Machine: For Hpb59-1 fasteners, set rolling speed 30-50m/min to avoid thread galling;
  • Tapping Centers: For internal thread fasteners (e.g., gear nuts), use high-speed steel taps to ensure thread smoothness (Ra ≤1.6μm);
    Machining parameters are adjusted by material: e.g., H62 brass uses higher cold heading pressure (800-1000MPa) than H68 (600-800MPa) to ensure forming quality.

6. Advantages of Brass Motor Gear Fasteners

 

1. Superior Anti-Loosening Performance: Brass’s coefficient of friction (0.3-0.4) is higher than aluminum (0.2-0.3), preventing fastener loosening under long-term motor vibration (loosening rate <1% in 5000-hour tests);
2. Low Maintenance Cost: Brass resists motor oil and humidity corrosion, no need for regular rust removal (maintenance cycle extended to 3-5 years vs. 1-2 years for carbon steel);
3. Noise Reduction: Brass’s damping coefficient (0.0015) is 2x that of steel, reducing gear meshing noise by 4-6dB, meeting low-noise motor standards (e.g., IE3 efficiency motors);
4. Cost-Effectiveness: Brass fasteners cost 30-40% less than stainless steel ones, and their high machinability reduces production waste (scrap rate <2% vs. 5% for aluminum).

7. FAQ about Brass Motor Gear Fasteners

1. Q: What is the service life of brass motor gear fasteners in automotive starters?
   A: Under normal use (1000-3000 starts/year), service life is 8-10 years; with nickel plating, it can be extended to 12-15 years.
2. Q: Can they be customized for miniature motors (e.g., 12V DC motors)?
   A: Yes, we support micro-fasteners (e.g., M2-M4 threads, length 5-15mm) with dimensional accuracy ±0.003mm, adapting to small gear assemblies.
3. Q: What thread accuracy grade is suitable for high-speed motors (≥8000 RPM)?
   A: Recommend 6g thread grade, which ensures meshing clearance ≤0.03mm, avoiding gear jamming at high speeds.
4. Q: Do you provide torque specifications for installation?
   A: Yes, based on fastener size (e.g., M6 bolt: 8-10 N·m; M8 bolt: 15-18 N·m) and motor power, we issue detailed installation guidelines to prevent over-tightening damage.

8. Customization of Brass Motor Gear Fasteners

 

• Demand Communication: Technical team collects motor power (kW), gear module (m), operating temperature, and fastening torque requirements to recommend materials (e.g., Hpb59-1 for high-precision threads, H68 for high-speed motors);
• Solution Output: Deliver 3D models (STEP/IGES format) and process plans within 2 days, clarifying cost (e.g., M5 custom bolts: $0.15-$0.25/piece) and lead time;
• Sample Production: Complete prototyping in 3-4 days, conduct torque and vibration tests (simulate 1000 motor starts) to verify performance;
• Mass Production: Support small batches (500-1000 pieces, delivery in 5-7 days) and large batches (10,000+ pieces, delivery in 10-12 days), with full-process quality tracking;
• After-Sales Guarantee: If fasteners loosen or deform within 1 year, we provide free replacement and technical optimization.