What factors should be considered in the assembly process of rotors and stators? How to improve the level of automation in production lines?

The assembly of both the rotor and stator has specific processes. Various factors need to be considered during design preparation and production to ensure smooth operation. So, what factors should be considered in the rotor and stator assembly process? How can the level of automation in production lines be improved? Below, Vacuz will briefly introduce this to you!

I. Key Factors to Consider in the Rotor and Stator Assembly Process

The rotor and stator are the core components of the motor, and their assembly process directly affects the motor’s performance, reliability, and production efficiency. The following are key factors to consider during assembly:

1. Mechanical Fit Precision

Dimensional Tolerance:

The axial clearance between the rotor and stator must be controlled within the design range. Excessive clearance will lead to decreased motor efficiency, while insufficient clearance may cause friction or even jamming.

Stator Inner Diameter and Rotor Outer Diameter: High-precision machining and online inspection are required to ensure dimensional consistency.

Axial Alignment: Using locating pins or end-face stop structures, in conjunction with servo press-fitting equipment, ensure that the axial alignment error between the rotor and stator is ≤0.02mm.

1. Geometric Tolerances:

Rotor dynamic balancing accuracy must reach G1 level. After stator core stacking, roundness and perpendicularity must be checked to prevent excessive vibration during high-speed rotation.

2. Electrical Performance Matching

Insulation Performance:

Stator windings and rotor cores must be isolated by insulating material. Withstand voltage testing must meet design requirements.

Insulation Treatment Process: Use VPI or drip impregnation processes to ensure an insulating varnish filling rate ≥95% and improve temperature resistance.

Magnetic Circuit Symmetry:

Stator slot dimensions must be consistent, and rotor magnet magnetization direction must be accurate to avoid magnetic circuit asymmetry leading to increased motor vibration and noise.

3. Assembly Process Stability

Pressure Pressing Force Control:

A servo press must be used when pressing the rotor into the stator. The pressing force must be monitored in real time to prevent excessive pressing force from causing core deformation or insufficient force from causing loosening.

Pressure Pressing Curve Analysis: Assembly quality is judged by the pressure-displacement curve. If a sudden change in force occurs, the machine must be stopped for inspection.

Cleanliness Control:

Before assembly, the stator cavity and rotor surface must be ultrasonically cleaned (e.g., with deionized water and alcohol) to remove metal shavings, oil, and other impurities to prevent short circuits or wear.

Cleanliness Standard: Particle size ≤ 50μm, quantity ≤ 100 particles/cm².

4. Environmental and Process Parameters

Temperature and Humidity:

The workshop temperature must be controlled between 20-30℃, and humidity ≤ 60% to prevent moisture absorption by the insulation materials, which could lead to a decrease in withstand voltage.

Special Process Environments: For example, the magnetization process must be carried out in an area free from magnetic interference (magnetic field strength ≤ 5mT).

Assembly Sequence Optimization:

Whether to adopt a “stator first, then rotor” or “rotor first, then stator” assembly sequence, the DOE (Design of Engineering) must verify which sequence reduces air gap deviation.

II. Strategies for Enhancing the Automation Level of Rotor and Stator Assembly Production Lines

Automation upgrades can significantly improve assembly efficiency (50%-200%), reduce labor costs (30%-70%), and increase yield (≥99.8%). The following are specific implementation paths:

1. Modular Equipment Integration

Automatic Loading and Unloading System:

Stator Line: Utilizes a gantry robot or six-axis robot with vision positioning to pick up stator cores from the hopper and place them at the pressing station. Cycle time ≤ 8 seconds/piece.

Rotor Line: Uses a vibratory feeder and linear feeder to sort magnets. Robots pick up and assemble them onto the rotor shaft. Cycle time ≤ 12 seconds/piece.

Multi-Station Turntable Machine:

Design a 12-station turntable machine that integrates cleaning, pressing, inspection, and gluing processes. A single machine completes 80% of the assembly process, reducing the floor space by 40%.

2. High-Precision Assembly Technology

Servo Pressing and Force/Position Monitoring:

A servo press, in conjunction with force and displacement sensors, provides real-time feedback of pressing data to the PLC. When the pressing force or displacement exceeds the set range, an automatic alarm is triggered and the machine stops.

3. Flexible Production Design

Quick Changeover System:

Quick Fixture Change: Utilizing hydraulic quick-change fixtures, it supports changing fixtures for different stator/rotor models within 10 minutes.

Program Switching: Assembly programs for different products can be accessed with a single click via HMI, reducing debugging time.

Mixed-Line Production Capability:

Reserved workstations are set up on the rotary table, and materials are dynamically allocated via AGVs, enabling mixed-line production of more than three motor models, increasing equipment utilization by 25%.

4. Digital Quality Control

Online Inspection and Data Traceability:

Air Gap Detection: Air gaps are measured non-contactly using laser displacement sensors, and the data is uploaded to the MES system in real time.

Dynamic Balancing Inspection: An integrated automatic dynamic balancing machine automatically marks imbalance locations after inspection, which are then corrected by robot weight removal or the addition of counterweights.

Data Traceability: Each motor is bound to a unique QR code, storing assembly parameters, inspection results, and operator information, supporting quality traceability.

5. Intelligent Logistics and Warehousing

Raw Material Delivery: AGVs automatically retrieve materials (such as stator cores and rotor shafts) from the automated warehouse and deliver them to the assembly line according to the production plan, reducing manual handling.

Finished Product Delivery: Assembled motors are automatically stored in the warehouse via a conveyor line, with the system updating inventory data in real time.

Summary:

The rotor and stator assembly process requires comprehensive optimization from four aspects: mechanical precision, electrical matching, process stability, and environmental control. Automation upgrades require five strategies: modular equipment integration, high-precision assembly technology, flexible production design, digital quality control, and intelligent logistics. The goal is to improve production efficiency, reduce costs, and ensure consistent product quality through “machine replacement of human labor” and “data-driven” approaches.

What factors should be considered in the rotor and stator assembly process? How can the level of automation in production lines be improved? The above provides a simple explanation of Vacuz, and I hope this information will be helpful!