What are the requirements for automatic assembly of brushless motor rotor parts and stators? What precautions should be taken?

The core components of a brushless motor are the stator and rotor. These two components complement each other and need to be assembled together, typically using specialized equipment. So, what are the requirements for automated assembly of a brushless motor’s stator and rotor? What precautions should be taken? Vacuz will briefly explain this below!

I. Core Assembly Requirements

High-Precision Fixtures and Drive Mechanisms

Fixture Design: The material must be wear-resistant (such as carbide), and the inner diameter must precisely match the outer diameter of the stator/rotor (with a tolerance of ±0.01mm) to avoid assembly play and uneven air gaps.

Drive Mechanism: A servo motor controls the rotation angle (with an error of ±0.1°) and speed (with a fluctuation of ±5%) to ensure accurate alignment of the rotor and stator.

Assembly Mechanism and Auxiliary Collaboration

Assembly Method: Pneumatic pressure is used for small motors, while hydraulic or electric pressure is used for large motors to ensure uniform pressure.

Real-Time Monitoring: Pressure sensors and displacement sensors provide feedback to prevent stator/rotor deformation.

Auxiliary Operations: The automatic lubrication system sprays molybdenum disulfide lubricant to reduce friction; the positioning mechanism must be calibrated to an accuracy of ±0.05mm.

Pre-treatment and Parameter Setting

Pre-treatment: Use an air gun to clean dust from the stator slots and wipe the rotor surface with alcohol to remove oil stains; use a caliper to check dimensions.

Parameter Setting: Adjust assembly speed based on power. High-power motors should reduce speed by 50% to maintain stability.

II. Key Points

Safety Operation Guidelines

After powering off, display a “Do Not Operate” sign and use a voltage tester to verify that there is no residual voltage.

Operators must wear cut-resistant gloves and explosion-proof goggles to avoid injury from flying magnet fragments.

During machine testing, monitor temperature rise with an infrared thermal imager. Vibration must be less than 2.5mm/s.

Key Points for Accuracy Control

Air Gap Testing: Use a plug gauge to measure the air gap at multiple points (e.g., 8 points for a 4-pole motor). The uniformity should be ≤±0.05mm.

Magnetic Flux Testing: Use a Gaussmeter to test the magnet surface (deviation ≤ 5%) to prevent torque fluctuations caused by magnetic flux distortion.

Dynamic Balancing: Adjust the balancing machine to G2.5 (ISO 1940), with residual unbalance <0.5g·mm/kg.

Environment and Equipment Maintenance

Ambient temperature: 20±5°C, humidity ≤60% RH, floor levelness <0.1mm/m (laser calibration).

Check the servo motor encoder monthly (resolution ≥17bit), and replace the hydraulic oil quarterly.

Vacuum the guide rails before assembly, and wipe the optical sensor lens with alcohol.

Parameter Monitoring and Adjustment

No-load current fluctuation: ±3% (rated current), three-phase unbalance <5%.

Load test temperature rise: ΔT ≤40K (GB755 standard), bearing temperature <90°C.

Data logs must include timestamp, operator, and current/temperature curves, and will be automatically archived in the MES system.

III. Solutions to Common Problems

Uneven air gap: First, check the fixture locating pins for wear (replacement cycle ≤ 100,000 times), then calibrate the servo zero point.

Abnormal noise and vibration: 80% of these cases are due to dynamic balancing errors and require rebalancing; for the remaining 20%, check the bearing clearance (axial ≤ 0.1mm).

Excessive temperature rise: Check the winding varnish for full coverage (porosity < 3%) or the magnetization consistency (deviation < 3%).

Through these standardized procedures and closed-loop quality control, we can ensure that assembly efficiency and quality meet requirements. Vacuz hopes this information will be helpful to everyone!

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