Magnetic powder clutch structure

A magnetic powder clutch with a cylindrical single-gap structure of a slip ring, a rotor 5 having a large inertia is coupled with a driven shaft 1 by a key, a coil 7 is mounted in a ring groove of the outer edge of the rotor, and is closed by a magnetic isolation ring 6, the housing 4 and The end caps 2, 10 are coupled to form an active member that can be rotated on the rolling bearing. The magnetic powder is filled in the gap between the casing and the rotor. In order to prevent the leakage of the magnetic powder, a very thin retaining ring 9 is fixed on both end faces of the rotor, and the leakage of the magnetic powder is blocked by the rubber oil seal 3 to prevent entry into the rolling bearing.

Magnetizer

For all kinds of magnets constituting the magnetic circuit, generally, soft magnetic materials with high magnetic permeability, low coercive force and small unit loss should be used. The commonly used materials are electrician pure iron [carbon content (mass fraction) 0.02%-- 0.025%], 10 steel for low-speed clutches of medium and small size, and 15 or 20 steel for clutches with high transmission torque. These materials must be properly heat treated to obtain good magnetic properties. In order to reduce the influence of the eddy current of the magnetizer and reduce the torque time constant, a material having a high resistivity such as silicon steel or an iron-aluminum alloy may be used. For less important clutches, it is also possible to use a more economical cast iron as a magnetizer.

Magnetic powder

Magnetic powder is the medium for transmitting torque and is the most important material in magnetic powder clutch. The requirements are as follows:

1 has high magnetic permeability and low coercive force to achieve high transmission torque. The residual torque after the current is disconnected is small.

2 Good heat resistance, no obvious oxidation at high temperature (300--500 °C), no sintering, no agglomeration, corrosion resistance, and can maintain the performance of the clutch for a long time.

3 The fluidity is good, and the clutch is quickly released after the coil is powered off.

For clutches that operate at speed differences, magnetic powders with high temperature and friction resistance should be used. For clutches operating in an automatic adjustment system, first consider the magnetic powder with high working stability.