KHK

Non-Contact Magnetic Gears

Magnetic gears use permanent magnets to transmit torque and rotational speed between shafts. Power is transmitted across an air gap, eliminating the mechanical friction typical of standard toothed gears.

Key Features:

• Clean operation: With no contact, there is no wear and no particle generation – a solution well suited to cleanroom environments.
• Lubrication-free: The system runs without oil or grease, reducing maintenance and preventing contamination.
• Transmission through barriers: Torque can be transmitted through sealed partitions without the need for shaft couplings.
• Built-in torque protection: In an overload condition, magnetic slip occurs, protecting the motor and the mechanical system from damage.
• Installation tolerance: The system tolerates a degree of shaft misalignment, both offset and angular, without affecting performance.
• Quiet operation: Noise and vibration are significantly reduced thanks to the absence of tooth contact.

Typical Applications:

• Semiconductor manufacturing equipment.
• Medical devices and diagnostic systems.
• Food, pharmaceutical and biotechnology industries.
• Pumping systems, fluid handling and vacuum environments.
• Robotics.

Product Range:

The series includes spur, bevel and worm gears, magnetic couplings, linear actuators and rack-and-pinion systems.

Operating Principle and Gear Ratios:

• Gear ratio: The speed ratio is determined by the ratio between the number of magnetic poles on each rotor.
• Speed reduction: Transmitting from a rotor with fewer poles to a rotor with more poles increases torque and reduces speed.
• Speed increase: Transmitting from a rotor with more poles to a rotor with fewer poles increases speed and reduces torque.
• Effect of the air gap: Transmittable torque depends directly on the distance between the rotors – as the air gap grows, magnetic flux density drops and torque decreases.
• Due to lost motion (a delayed response caused by the elasticity of the magnetic field), the product is not suitable for positioning applications that require high accuracy.

More on Specialized Product Lines

Beyond the standard gears, the series includes dedicated solutions:

• Variable-speed magnetic gears: Available in disc or cylindrical configurations, they offer high design flexibility in gear ratios. They allow rotational speed and torque to be reduced or increased without physically changing gears, providing a versatile solution for systems that require a range of gear ratios.
• SmoothSlip coupling: Functions as a standard coupling under normal conditions, but becomes a torque limiter when torque exceeds the permitted limit. Unlike conventional mechanical mechanisms, which may chatter or “jump” under load, a special engineered magnetic material enables smooth, continuous slip that protects the motor and equipment without sudden shocks.
• Magnetic Linear Motion:
• Magnetic linear actuators: Designed for cleanroom transport applications. Unlike conventional linear motors, they require no complex electrical wiring along the track and can be extended to virtually unlimited lengths.

• Rack and pinion: A non-contact version that converts rotary motion into linear motion using magnetic force alone, preventing wear and particle generation.

For mor information: KHK non-contact Magnetic Gears