In automotive HVAC actuator systems, motor selection is evolving from a single-model approach to a multi-solution strategy. Traditionally, the SF-266 (2126 size) motor has been widely used as a standard solution for air flap control. However, as vehicle requirements for performance, NVH, and durability increase, the RF-370CB (2430 size) motor is becoming a preferred option for higher-demand applications.

Understanding the differences between these two motor types is essential for engineers and procurement teams aiming to optimize system performance.

HVAC actuators operate in short bursts rather than continuous motion, requiring reliable start-stop performance.

Motors drive gear systems to achieve precise flap positioning, emphasizing smooth and stable output.

Dashboard integration requires compact motor designs such as 2126 and 2430 structures.

• SF-266 (2126): Compact size (~21×26mm), ideal for space-constrained designs
• RF-370CB (2430): Larger size (~24×30mm), offering higher power density

 Conclusion: RF-370CB provides stronger output but requires more space

Common Motor Series  For Car HVAC Actuator
SF-266SH & RF-370CB 

• SF-266: Suitable for standard airflow control loads
• RF-370CB: Higher starting torque for demanding conditions

 Typical use cases:

• Larger air flaps
• High-resistance sealing structures
• Aging systems with increased friction

Thanks to its larger armature and improved commutation system, RF-370CB typically delivers:

• More stable start-stop behavior
• Longer cycle life under repeated operation

With increasing focus on cabin comfort:

• SF-266: Meets standard NVH requirements
• RF-370CB: Offers improved noise and vibration control

 Ideal for mid-to-high-end vehicle applications

• Extremely limited installation space
• Low-load air flap systems
• Cost-sensitive projects
• Standard HVAC actuator designs

• High mechanical resistance or sealing loads
• Higher NVH performance requirements
• Need for enhanced reliability and durability
• Existing issues with insufficient torque from 266 motors

Avoid relying solely on no-load specifications—validate performance in actual actuator systems.

Check starting and operating current to match ECU capabilities and avoid overload issues.

Proper gear ratio selection reduces motor stress and improves system efficiency.

Allow for performance degradation over time by selecting motors with sufficient margin.

SF-266 and RF-370CB motors are not competing solutions but complementary options for different HVAC actuator requirements. While SF-266 suits compact and standard applications, RF-370CB provides a more robust solution for higher load, improved NVH, and long-term reliability.

Application-based motor selection is the key to achieving optimal performance, cost efficiency, and system durability in modern automotive HVAC systems.