Principle of the motor（1）

13 Jan Principle of the motor（1）

Motor：Because the first mobile phone vibrator was a small motor belt moving eccentric block, so the popular vibrator is also called the motor.
A vibrator is a device that provides vibration in a mobile phone. With the exception of mobile phones, other products are rarely used to the vibration function.
Vibrator classification
1.Rotating motor:Cylindrical, flat and brushless

2.LRA motor:Z axis direction, X axis direction, three in one

Vibration source

Vibration quantity a(unit of acceleration)：a=mxf²/ M
key parameter
1.Steady-state performance index
Rotating motor: speed, start, noise
LRA motor: vibration, noise, f0
2.Transient performance indicator response time (start, cut-off time)
3.Electrical indicators
Resistance, rated current
Assembly of vibrator in mobile phone

1.When the driving force of the motor does not pass through the center of mass, the load has both translational and rotational motion states.
2.The strength of hand vibration is generally measured by the part of the phone that has the greatest vibration.So the rotational state is much larger than the translational state.
3.The amplitude of rotation is proportional to the torque, so the farther the driving force of the motor is from the center of mass, the stronger the vibration force of the hand.
4.The motor needs to be mounted as close to the corners as possible to get greater vibration.
The four elements of linear motor
1.Spring k
2.Mass m
3.Driving system
4.Damping R
LRA motor structure
1.Weight: corresponds to a small mass m
2.Damping: magnetic fluid and self damping
3.Spring sheet/spring bracket, no matter what shape: the corresponding connection spring.
4.Electromagnetic part: provides force to swing the weight