Structure and working principle
The magnetic powder clutch is composed of active rotor(input shaft),driven rotor(output shaft) and Yoke wit execitation coil. The three parts are assembled relative concentric and form a system which can rotate relatively. The annular gap between active rotor and driven rotor is full of alloy powder which has high magnetic conductivity.
The magnetic powder will bein the states of loose when the current do not pass the excitation coil.The magnetic powder will be thrown on the inner wall of active rotor. In this case ,there will not exist the interaction force between the active and driven rotor. So the magnetic powder clutch is in the state of separation , no torque transmission extis.
The magnetic powder in the working chamber will link in a link state under the action of the magnetic flux generated from the Yoke when the current pass the excitation coil. The magnetic powder clutch can transfer torque relying on the shear force generated from magnetic chain and the friction generated from the magnetic powder and working face. In this case the magnetic powder clutch is in the state of combination.
When the current is cut off,the magnetic flux will disappear with the disappearance of the magnetizing current ,the magnetic powder will be in the state of loose under the action of gravity again,and will be thrown on the inner wall of active rotor under the action of the centrifugal force. In this case ,the magnetic powder clutch will be in the state of separation again.
The magnetci powder clutch and brake have the same principle,the magnetic powder brake will form as long as the driven rotor of the magnetic powder clutch is fixed。
The magnetizing current has a linear relationship with torque
As is shown in chart 3,the transmission torque has a linear relationship with the magnetizing current, The size of the torque can get controlled within larger range.Under normal circumstance,the magnetizing current has a linear relationship with transitive torque within range of 5%-100% rated torque.
Stable slip torque
The slip rotational speed between driven rotor and active rotor do not affect the transitive torque when the magnetizing current retain unchanged, as shown in chart 4 ,That is to say,the static friction torque and the dynamic friction torque have no difference. Therefore, the torque can retain constant stably.The features are applied to tension control,users can control the tension of the roll material effectively as long as adjust the magnetizing current accurately.
Prevention heat phenomenon from slip
The friction part will generate heat inevitably or even destroyed when it keep continuous sliding .But this device has a complete cooling set ,it will not generate a lot of heat after long time running and it has a long service life.
Due to the features of the magnetic powder clutch and brake, they have been widely used in paper making,printing,plastic items,rubber industy,textile industry printing and dyeing,wire and cable,metallurgy industry and tension control of winding and unwinding in roll material processing industry.A complete set of schematic of tension control system is as follows.