Clutch#Multiple plate clutch

A multi-plate clutch or Reiblamellenkupplung is a machine element. Their characteristic feature in comparison with other couplings is the arrangement of multiple linings in series. The same contact force acts on all Reibpaare.

Multi-plate clutches are switchable under load. They are often used because they are compact and inexpensive. Mostly these are running, mainly in automatic transmissions in oil, in highly loaded main or starting clutches or locking differentials in use. In Construction axes multi-plate clutches are also used as service and parking brakes, the latter often in the form of a spring -loaded brake. The advantages are its high power and energy absorption as opposed to dry clutches, because here is cooled with oil. Disadvantages include lower friction (such as μ = 0.08 .. 0.12 ), to dry clutches and a higher drag torque at idle.


A Reiblamellenkupplung consists of at least an inner and an outer plate. The inner plates are splined to a shaft and the outer plates are received by an internally splined, tubular support. To increase the torque to be transmitted, a plurality of inner and outer plates are alternately arranged so that at the same actuation force greater torques can be transmitted by the larger surface area of times.

In practice, the number of friction plates is limited to 10 to 20 slices, since the dynamic engagement of the friction plates are pushed together and each friction plate must move towards their leadership. This part of the operating force is not propagated to the adjacent friction plate, but supported on the plate carrier. The friction torque which transmits each lamella, thereby falls in direction of force application from the first to the last friction plate from a sliding scale.


In oil-lubricated ( wet-running ) multi-disc clutches can run against each other with sufficient lubrication steel disks (alloys with addition of molybdenum ). In practice, however, either the slats are coated or it will be used blades made ​​of other materials. Thus, the coefficients of friction can increase, improve the temperature resistance, as well as achieve a smoother response or a reduction of operating noise.

Common friction materials are:

  • Paper pads get their name from the fact that they are manufactured in the same process as paper. This type of friction materials in oil, is most commonly used. If they are axially pressed together, they allow surface pressures during dynamic operation of up to 2 N / mm ². In the static mode, the value is significantly higher. Here, the surface pressure nominal amount to 7 N / mm ², locally they can be twice as large to.
  • With carbon fiber surfaces (carbon deposits ) mostly woven carbon fiber is used. The mostly -woven fibers increase the strength of the pavement. Furthermore, as carbon fibers are (similar to the paper surface ) was used as a complete covering. In principle, also carbon fiber pads in the paper method can be produced, because of the high blending and the cost of the material woven mats are present but punched out of carbon fiber and the carrier (usually a steel plate ) glued. Woven Carbon pads allow surface pressures up to about 6 N / mm ², but are more expensive than paper coverings.
  • Advantages of the sintered bronze are the high thermal and mechanical strength. However show sintered bronze pads in the clutch package a lower power consumption than, for example high temperature resistant Papierreibbeläge. Disadvantages are lower dynamic friction coefficients than paper linings.
  • Pressed graphite offers advantages similar to those of sintered bronze, but is lighter.

Wear and damage patterns

Aging and overload result in multi-plate clutches to various effects:

  • Normal wear and tear increases the actuation path. This can be compensated by an automatic adjustment.
  • Overheating at the surface of the flooring can glaze them. The coefficients of friction decrease and thus the transmissible torque. Typically, this damage will not be undone by normal wear and tear.
  • If the friction materials are connected to a steel plate, the adhesive can soften the event of overheating and the friction lining moves or dissolves. The function of the clutch is no longer guaranteed.
  • In wet clutches can be chemically altered by permanent high temperatures the coolant. In this example, oil can lead to increased oxidation or cracking of oil molecules.
  • Hot spot or hot spots: This is caused by local thermal concentration between the lining and steel slat counter a buildup of heat and associated expansion. The resulting " thermal mountain or hill " called hot spots or heat spots. Occurrence due to uneven accumulation of material and high performance entry in the clutch.

Development and Research

A field of intensive development and adaptation is the noise avoidance in Reiblamellenkupplungen caused by self-excited friction vibrations. The overall system of this tribological relationship between Friction and-in wet clutches, the lubricant must be considered.

In addition, the temperature and wear resistance is another area of research. Especially with carbon fiber reinforced linings, the aging resistance and the softening temperature of the matrix material must be as high as possible.


  • Clutch -controlled all-wheel drive and locking differentials in the automotive industry
  • In the special case Torque limitation in cordless screwdrivers
  • Switching elements in gearboxes
  • Clutch in vehicles with internal combustion engines
  • Couplings in motorcycle engines with manual transmissions ( advantage of saving space )
  • General: Where the separation of waves for a short time is required.