Engineered for high winding accuracy, minimal wire enamel friction, and tight dimensional tolerances across EV alternators, starter motors, and precision industrial power tools.
Achieving optimal slot fill factors, uniform dielectric clearances, and mechanical stability in heavy-gauge round and rectangular wire applications.
The post-insertion phase requires exacting mechanical force. Automatic stator coil expanding machines utilize internal radially expanding mandrels to flare and set coil overhangs. This prevents inter-phase electrical breakdown, minimizes overall axial stack envelope, and clears necessary mechanical tolerances for rotor insertion and end-bracket assembly.
Manual expansion risks tensile strain beyond copper plastic thresholds, leading to partial discharge failures under high-voltage inverter surges. China's top tier tooling integrates precision servo-hydraulic expansion kinematics and polished tungsten-carbide fingers that maintain constant friction coefficients below 0.12 μ.
With electric vehicle (EV) traction drive motors transitioning toward rectangular flat wire, the demand for dual-axis wedge expanding and crown-end opening has skyrocketed. State-of-the-art expansion tooling applies progressive multi-point force, safeguarding the slot liner paper and phase barriers from mechanical rupture.
Founded in 1998 in Sanmen, Taizhou, Rilvo integrates in-house precision tooling, digital control software, and complete production line systems under one 60,000 m² campus.
Every stator winding, coil embedding, and slot expanding machine is manufactured under strict ISO9001 quality management routines and certified by China Compulsory Certification (3C). Full traceability across heat-treated alloy steels and electrical components guarantees 24/7 industrial longevity.
We do not outsource core tooling components. Our 150+ dedicated machine tools manufacture hardened expanding fingers, insertion blades, and coil pushers in-house. This ensures concentricity tolerances within ±0.005mm and delivers rapid tooling turnaround for custom customer lamination stacks.
Beyond individual stator expanding units, Rilvo delivers fully automated production lines integrating paper inserting, high-speed multi-axis winding, wire embedding, intermediate shaping, final expanding, and automatic horizontal trickle impregnation (Model DQ-226/100).
Exporting to over 40 countries across Eastern Europe, Southeast Asia, Latin America, and the Middle East. Situated just 2 hours from Ningbo Port, our equipment features multi-lingual PLC HMI panels (EN, ES, DE, RU, PT, FR) and pre-shipment customer sample testing verification.
How the global electrification wave is reshaping technical requirements for stator coil expanding, shaping, and inserting systems.
The push for EV efficiency requires slot fill ratios climbing above 75%. Traditional round-wire expanding machines are increasingly supplemented by 3D segmented expanding dies capable of calibrating the complex crown and weld ends of 8-layer and 10-layer flat copper wire stators without cracking the insulation varnish.
Modern procurement guidelines from European and North American Tier-1 suppliers mandate 100% digital data logging. Modern expanding systems integrate load cells and high-resolution optical encoders to trace force-versus-stroke curves for each individual stator slot, instantly flagging tight slots or skewed laminations before varnish baking.
With high-mix low-volume production spreading across industrial pump, power tool, and drone motor sectors, manufacturers can no longer afford 4-hour retooling downtime. Current machinery designs utilize zero-backlash quick-release pneumatic lock systems, allowing complete fixture swap and recipe change in under 15 minutes.
Procuring custom motor automation machinery from China requires verifiable risk mitigation. At Zhejiang Rilvo Automation Equipment Co., Ltd., international clients are provided with full video trial verifications using their custom lamination samples prior to final balance payment and ocean dispatch.
Our 36 R&D design engineers match tooth geometry, stack height, and slot openings directly against your CAD drawings, guaranteeing seamless plug-and-play field commissioning.
Essential technical and commercial clarifications addressed directly by our senior motor tooling engineering desk.
During automated stator assembly, the inserting machine pushes the pre-wound wire bundle and insulating wedge paper into the stator core slots. Because the copper wires are loose and flared outward post-insertion, an intermediate shaping machine compresses the end-turns axially and radially. Finally, a stator coil expanding machine pushes an internal segmented mandrel outward from the inside bore. This expands the inner coil diameter, ensuring complete rotor clearance while flaring the outer diameter to provide electrical insulation gap distance from the stator metal frame.
Our tooling employs high-grade Cr12MoV or cemented carbide expansion sectors, vacuum heat-treated to HRC 60–62 and mirror-polished with Ra < 0.05 μm roughness. Furthermore, expansion kinematics are driven either via controlled multi-stage servo cams or proportional hydraulic valves that ramp velocity smoothly, avoiding high-impact shock loads that crack polyurethane or polyamide-imide insulation coatings.
Yes. For identical core diameters with varying stack heights, the machine stroke length and limit positions are adjusted digitally via the PLC touch screen in seconds. For stators with different internal bore diameters, outside diameters, or slot numbers, modular expanding core dies and clamping jaws can be exchanged via our quick-disconnect alignment system in under 15 minutes.
To provide an exact mechanical proposal and tooling layout, our engineering team requires:
1. Stator lamination drawing (.DWG / .DXF / .STEP) showing inner bore, outer diameter, and slot dimensions.
2. Minimum and maximum stack lamination heights.
3. Magnet wire details (wire diameter, single or multi-strand count, copper or aluminium).
4. Target cycle time (seconds per part) and factory operating voltage/pneumatic supply.
We supply under Incoterms 2020: FOB Ningbo/Shanghai, CFR, CIF, and EXW terms, accepting T/T and irrevocable L/C in USD or EUR. Every machine includes a 12-month standard warranty, full operational manuals in English, wear-part spare kits, and lifetime PLC remote support. Onsite engineer installation and operator training are available worldwide for complete production line deployments.
Send your stator or armature CAD drawings today. Our 36-member R&D engineering team will provide a tailored tooling proposal, cycle time calculation, and direct factory price quote within 24 hours.
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