Automotive A/C Clutch Coil - Project Details

Automotive clutch air-core coils are characterized by core advantages such as high-speed response, lightweight design, and high-temperature resistance; consequently, key areas for optimization include inductance, DCR, heat dissipation, and EMC. In the future, driven by the advancement of vehicle electrification, the application of these coils in hybrid and purely electric vehicles is expected to expand further. Within automotive clutch systems, the application of air-core coils is primarily concentrated in electromagnetic clutches—such as those found in air conditioning compressors, automatic transmissions, and the power coupling systems of hybrid vehicles. By energizing the air-core coil to generate a magnetic field, the armature plate is engaged, thereby enabling the transmission or disconnection of power. Furthermore, air-core coils are utilized to precisely control the magnetic field, facilitating friction-free power switching between the electric motor and the internal combustion engine.

Video

Applications

❖ Electromagnetic Clutch Systems: A/C compressors, automatic transmissions, hybrid powertrain couplers

❖ Electric Power Steering (EPS): Steering torque sensors, EPS motor stators

❖ Hub Motors / Wheel-Side Motors: Pure electric and high-performance AWD vehicles

❖ Energy Recovery Systems: Regenerative braking current sensors, wireless charging receiver coils

❖ Electromagnetic Active Suspension: Adjusts damping force via hollow coil arrays to enhance ride comfort

❖ Automotive Electronics & EMC: Common mode chokes, keyless entry systems

Winding Considerations

The core requirements for winding hollow coils for automotive clutches are material thermal resistance, winding precision, and thermal management design; a balance must be struck between electrical performance and mechanical strength. Production processes require strict control over winding tension, insulation integrity, and testing protocols.

❖ Material Selection: Priority is given to flat copper wire or multi-strand twisted wire (such as Litz wire) to minimize the skin effect (critical for high-frequency applications). The coil bobbin (former) should be constructed from high-strength, heat-resistant materials (e.g., PEEK plastic or ceramics) to prevent deformation under high temperatures.

❖ Winding Process: Multi-layer close winding is employed to maximize inductance; however, strict control over inter-layer insulation is essential (typically achieved by inserting an insulating film between each layer).

❖ Thermal Management: Integrated forced cooling systems are required; high-power clutch coils (such as those found in hybrid vehicles) must incorporate embedded cooling channels (utilizing oil or water cooling).

❖ Vibration Protection: Following the winding process, Vacuum Pressure Impregnation (VPI) is applied to enhance vibration resistance (meeting 20G vibration test standards). The outer layer is encapsulated in silicone or epoxy resin to provide protection against moisture and oil contamination (achieving an IP67 rating).