How a Sealed Electric Motor Stays Cool Inside

This patent describes a brushless direct-current (BLDC) motor sealed in an airtight compartment that uses openings in its spinning rotor to create an internal airflow, cooling the motor by transferring heat to the end caps.

What it covers

This electric power apparatus features a brushless direct-current (BLDC) motor supported by a main planar body. The motor's stator and rotor are enclosed within a substantially airtight sealed compartment, formed by a first end cap and a second end cap. Crucially, the rotor includes a series of openings in its radial wall. As the rotor spins, these openings generate an airflow that circulates within the sealed compartment, effectively transferring heat from the stator to both the first and second end caps, which then dissipate the heat.

What it doesn't cover

• —Does not cover electric motors that are not brushless direct-current (BLDC) motors.
• —Does not cover motors where the stator and rotor are not enclosed in a substantially airtight sealed compartment.
• —Does not cover cooling systems that do not generate airflow using openings in the rotor's radial wall.
• —Does not cover motors where heat is primarily transferred to components other than the first and second end caps.
• —Does not cover motors that rely on external fans or liquid cooling systems for primary heat removal.

The clever bit

The cleverness lies in using the rotor's own rotation, specifically through designed openings in its radial wall, to create a self-contained airflow for cooling within a sealed motor compartment. This avoids the need for external fans or complex liquid cooling systems, simplifying the design while maintaining environmental protection.

Why it matters

Sealing a motor protects it from dust, moisture, and corrosive environments, which is vital for reliability and lifespan in many applications. However, sealing also traps heat. This patent addresses that challenge by providing an integrated, active cooling mechanism within the sealed space, allowing BLDC motors to operate efficiently and reliably even in harsh conditions without external cooling components.

Real-world examples

• 1.Robotic actuators for industrial automation
• 2.Electric vehicle components operating in dusty or wet conditions
• 3.Medical devices requiring sterile or sealed environments
• 4.Aerospace components where environmental protection is critical
• 5.Submersible pumps or marine propulsion systems