Centrifugal clutch

A centrifugal clutch is a clutch that is produced in the power circuit, by, provided with clutch linings, mobile flaps or slides are drawn by the centrifugal force with increasing speed to the outside, making contact with the inner wall of the coupling housing ( clutch drum ) is made, which also serves as the output.

As an alternative, the centrifugal force-controlled clutch, usually simply called also centrifugal clutch, wide acceptance. In contrast to the arrangement described here is, this is a disc or multi-disc clutch, which is controlled by a structurally separate, trivial centrifugal pendulum.

• 3.1 Kickstarter
• 3.2 -way clutch
• 3.3 slipping clutch
• 3.4 centrifugal brake

Properties

Centrifugal clutches work independently. The transmissible torque depends on the speed. At speed droop separate them automatically by a single circumferential return spring or a return spring per valve or slide.

Of the spring force can be adjusted, for example, that the engine is disengaged idle. Increasing the rotation speed, as the clutch engages, and the motor provides a torque on the output shaft. Characterized is possible without any additional intervention by the operator control such as a start of an internal combustion engine.

Since only one side of the clutch may influence the deflection of the flap or vane, a centrifugal clutch in the non- coupled state acts depending on the direction; this direction dependency refers to the direction of the force flow, and not the direction of rotation. Is the power circuit but made ​​only once, the torque to hold the speed and thus the engagement of both sides can be applied.

Designs

Tangential

In the tangential embodiment flaps are mounted on pivot points in the vicinity of the periphery. This embodiment has the advantage of being simple and robust. The disadvantage is that only a small part of the bell circumference ( usually less than 50 %) can be used for power transmission. Since the pads are to be evenly worn, they must not be mounted too close to the axes of rotation of the flaps.

Furthermore, an additional indirect effect of increasing the contact pressure is possible. To this end, the flaps along the radius is also provided with a coating (see figure). Swing the cover open, this coating is tilted and thereby presses the loose end of the adjacent flap in addition to the bell. This version can already achieve a high contact pressure at low speeds.

Radial

The radial design are not moving flaps, but slide along two or more radii of the bell. This allows the entire slide surface are provided and used to go to the bell with a coating, so it will become apparent efficiencies of the bell surface of almost 100 %. A disadvantage of this embodiment, the slider mechanism, this is sensitive to tilting and therefore needs to be made ​​more precise than an axis of rotation.

Applications

The moped shown in the middle picture has two antiparallel centrifugal clutches on an axis: the internal causes as Kickstarter the connection of start pedals and motor (middle figure), the outer and idle coupling the connection of the motor and wheel ( upper figure). The combined construction each uses the bell of a clutch as a carrier of the flaps of the other.

Kick-starter

The flaps of the inner clutch are mounted on the outer bell, the outer part of the coupling. Not visible in the middle picture - - inner bell mounted on the inner flaps is. If one takes the pedals, the inner flaps rotate. If sufficient speed is reached ( a kick will suffice), the inner bell is hitched and started the motor connected to its axis.

Coast clutch

After starting the mopeds shown, the axis of the inner clutch bell now rotates by the torque of the motor. The pedals are quiet again, the kick starter clutch is released. The output ( external bell) at rest, the drive ( internal bell) is idle. By accelerating the speed of the motor, the inner bell and attached to their outer flap is then increased (pictured above). With sufficient speed, the outer globe is coupled and the motor connected to the wheel.

Even with electric motors that have to move a large mass ( eg a heavy stirrer, a so-called heavy starting ), centrifugal clutch came earlier increasingly used. They served to relieve the motor in the low speed range, since induction motors without current displacement rotors have their stable operating torque beyond a mountain at high speed and this operating in heavy start, therefore, can not be achieved. Through the development of special types of runner, start circuits and frequency however, this is not a common use nowadays more.

Slip clutch

In Karts a robust centrifugal clutch is often installed because it simultaneously braking and acceleration is possible (high speed of the drive clutch slips on braked output ). Kart engines have their highest torque at high speeds. Therefore, this driving technique is applied to curves, to get back to have available immediately after releasing the brake on corner exit immediately the full motor torque.

As a safety element, the centrifugal clutch is used in this form. Blocks such as the prime mover, the clutch opens by the reduced speed and the output is running free. This can keep the prime mover from serious damage.

Centrifugal brake

Fixed to the output side, we obtain a centrifugal brake. It preserves machines or structures with rotating elements against overspeed. Centrifugal brakes are often used in summer toboggan runs are used.