By: Brad Proffitt, SM Magnetics Account Manager

Vibration and haptic motors are the common means used to provide feedback from a signal or touch. The feedback is vibration. Vibration is an effective indicator that an action has responded from a software or hardware. These vibratory and haptics motors are in many items we utilize every day. Consumer electronics, Home appliances, Automotive, and many health products.


Tell me if one of these situations sounds familiar? You have a gaming controller in your hand, an action happens during game play and the controller rattles and shakes in your hands. Your children are playing with their favorite red sesame street plush toy, it laughs and shakes with hilarity when you play with it. Or more commonly, you have a call occur on your smartphone and it buzzes and vibrates on a table indicating you to pick up. While these are just a few examples, these actions are all created from Vibration Motors.


The basic vibratory motors are divided into 2 types and these are the ERM and LRA:


  1. ERM or Eccentric Rotation Mass
  2. LRA or Linear Resonant Actuator


Both ERM and LRA are driven by the interaction between electrical magnetic field and magnetic field. Converting electrical energy into mechanical energy in the form of rotation or vibration. ERM vibration motors create an off-center rotation via loading a counterweight (eccentric weight) on a shaft or a configuration plane. LRA vibration motors vibrate on a single axis against a spring, composed of Z-axis LRA (vertical direction LRA) and X/Y-axis (horizonal direction LRA).

ERM and LRA vibration motors can vary from the way of vibration and form factor as described above. ERM motors are divided into cylindrical configurations with shaft loading mass and coin shape configurations. Other ERM motors include iron core rotatory motor, automotive motor and sonic motor. LRA motors are varied by the linear vibration direction, X/Y-axis or Z-axis.


Permanent magnets are a basic part in a typical haptic motor, which is used to interact with electrical field to generate magnetic induction, this is why the electrical energy can be converted into mechanical energy. For a typical ERM motor, laminations stackings are the fundamental component to stabilize and enhance the electrical magnetic field. For a typical LRA motor, there are no laminations, but vibration spring with specific frequency and moving mass (magnet + other mass) driven AC voltage is very critical. For both ERM and LRA, coils are the sole source of electrical magnetic field.  


Vibratory motors are customizable based on the customers’ application and constraints, such as the way of vibration, the acceleration strength, response time, size, work voltage and current.


About SM Magnetics: SM Magnetics is privately owned company, providing assistance with permanent magnets, magnetic design & optimization, engineering support, and production.  SuperMagnetMan is the online retail division of SM Magnetics offering neodymium magnets and other materials.


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