DC servo motors achieve precise mechanical motion regulation through armature voltage or magnetic flux control. Their basic structure is similar to ordinary DC motors, but they are structurally optimized for control system requirements, such as a slender armature design to reduce rotational inertia.
These motors are divided into brushed and brushless types: brushed motors offer advantages such as low cost and wide speed range, but require brush maintenance; brushless motors achieve maintenance-free operation through electronic commutation and are suitable for high-performance applications. With their high response speed, large starting torque, and smooth operation, they are widely used in automation control, industrial robots, CNC machine tools, and other fields.
DC servo motors consist of the following core components:
Stator (Magnetic Field System): Typically uses permanent magnets (such as neodymium iron boron) or electromagnets. Permanent magnet stators require no additional excitation, are small in size, and highly efficient, with magnetic field strengths reaching 0.5~1.2 Tesla (data source: Electrical Engineering Handbook).
Rotor (Armature): Constructed of laminated silicon steel sheets with embedded winding coils, powered by brushes that contact the commutator. The rotor diameter typically ranges from 20 to 100 mm, directly affecting torque output.
Commutator and Brushes: The commutator consists of copper plates and works with brushes to switch the direction of current. High-performance servo motors use metal-graphite brushes with a lifespan exceeding 5000 hours (reference: ABB technical white paper).
Sensors (Encoder/Resolver): Includes built-in position feedback devices, such as photoelectric encoders with a resolution of up to 17 bits (131072 pulses/revolution), ensuring closed-loop control accuracy.