The SMC stator core, with its excellent magnetic properties and lightweight characteristics, has become a key material support for frameless torque motors to achieve high power density and high responsiveness.
Definition of Frameless Torque Motor
A frameless torque motor is a special type of permanent magnet synchronous motor. Its core feature is that it has no traditional housing, shaft, bearings, or end caps, consisting only of two independent components: stator and rotor.
Advantages of SMC Stator Core
| Manufacturing Process: SMC adopts integral die-casting forming. It does not require complex stamping, stacking, and riveting processes, which greatly simplifies the manufacturing process, improves production efficiency and product consistency, while reducing material waste and achieving “near-net shaping”.
| Low Loss: SMC is formed by pressing iron-based powder particles coated with insulation layers (such as oxides or resins) on the surface, with particles insulated from each other. This structure greatly increases the electrical resistivity of the material, effectively suppressing eddy current loss at high frequencies. This characteristic performs excellently in high-frequency applications, suitable for high-speed, high-frequency direct-drive scenarios.
| Lightweight: SMC material has low density, and the integral forming design eliminates gaps between laminations. Compared to traditional silicon steel motors, SMC stators can reduce weight by 15%-30%, meeting the lightweight and compact design requirements of frameless torque motors.
Limitations of SMC Stator Core
| Poor Mechanical Stress Resistance: SMC material has much lower mechanical strength than traditional silicon steel sheets. This makes SMC parts prone to deformation or permanent damage when subjected to large mechanical stresses or impacts, limiting their application in extremely high mechanical load scenarios.
| Higher Cost: SMC uses high-purity iron powder, insulation coating materials, and binders, and requires complex powder metallurgy processes. Its comprehensive material and manufacturing costs are generally higher than traditional silicon steel stamping and stacking processes.
Product Parameters of SMC Stator Core
| HM-S3 | HM-S4 | HM-S5 | HM-S6 | HM-S7 | HM-S8 | |
| Average Particle Size (µm) | 212 | 212 | 212 | 105 | 212 | 212 |
| Apparent Density (g/cm³) | 3.28 | 3.35 | 3.18 | 3.05 | 3.16 | 3.3 |
| Compressibility (g/cm³) | 7.61 | 7.63 | 7.52 | 7.3 | 7.52 | 7.5 |
| Electrical Resistivity (µΩ·m) | 120 | 165 | 90 | 9000 | 600 | 700 |
| Maximum Permeability (umax)) | 750 | 850 | 720 | 400 | 770 | 600 |
| Saturation Induction (Bm, T) | 1.62 | 1.63 | 1.59 | 1.45 | 1.57 | 1.57 |
| Core Loss (W/kg) @ 0.8T 1kHz | 85 | 83 | 82 | 86 | 84 | 60 |
Applications of Frameless Torque Motors
Frameless torque motors are commonly used in application scenarios with limited space and high torque requirements, such as humanoid robots, quadruped robots, and other similar scenarios.
Magnets Manufacturer
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Focussmc & Hmg-mim & & Linengineering & Researchgate & Jmag-international
