# علبة التروس الدائرية

Cycloidal gearbox is a kind of mechanical gear. It is used to transmit power from one mechanical device to another. The gears are generally cylindrical in shape and have a large number of teeth. The cycloid shape is achieved by generating a gear that has geometrical relations. The gear is made by machining it using a mathematical model that includes kinematics parameters, output moment calculation, lobe undercutting elimination, and more. Some of the research work is dedicated to its efficiency and power loss calculations.

## Iterative process

This article describes the iterative process in cycloidal gearbox design. In this method, the mechanical parameters for a cycloid disc and ring gear roller are optimized for the same contact point. FEA dynamic simulation was conducted to study the cycloid disc profile at various time points during an operation cycle. This study also presented an optimization method that is able to predict the cycloid disc’s impact motion with the outer rollers.

The Iterative process in cycloidal gears was first implemented by calculating the backlash and torque fluctuations of a cycloidal gearbox. Then, it was designed and fabricated at Radom University. The researchers changed the backlash by inserting two pairs of cycloidal discs, one with a profile that was offset from the nominal, and the other with a profile that was at the middle of the tolerance. Then, they modified the diameter of the output pin holes in order to accommodate the minus tolerance.

## Mesh density

Cycloidal gearboxes are very versatile and are often the preferred transmission option. Their large transmission ratio, high efficiency, and compact size have made them popular in many industrial settings. These gear reducers have become increasingly popular for precision transmission, because the geometry of cycloidal gears allows them to mesh half the teeth at the same time. This averaging effect results in high precision and stiffness.

The development of a cycloid pin wheel transmission requires discretization of the gear teeth and kinematic and contact analysis. Angular contact analysis is used to solve the contact stress, and a progressive mesh densification method is employed to determine the meshing area. Using the Hertz contact theory, the maximum contact pressure and average film thickness were obtained at various points and after contact deformation.

## Vibrations

In this article, the authors analyze the problem of cycloidal gearbox vibrations. The cycloidal gearbox has internal and external pins. The external pins influence the most on the amplitude and torque fluctuation. Backlash is another factor that influences cycloidal gearbox vibrations. Changes in the diameter of the output pin hole and cycloidal discs are some of the methods that introduce backlash. The results of the experiments were presented in frequency and time domain.

The cycloidal gear has a special design principle that eliminates the need for gear teeth in the output stage. This reducer offers greater shock resistance than traditional reducers. Some variations are able to withstand transitory exposure to quadruple the torque. Furthermore, the torque density allows ratios up to 185:1 in a reasonable gearbox footprint. In addition, cycloidal gears are highly efficient.

## Strength

Cycloid gearboxes are a versatile gearing solution. They reduce input speeds by 87:1 or higher in one stage. Cyclo(r) CNH609-15 cycloidal gearbox has a ratio of 15:1 and is foot mounted. However, its low reduction ratio results in greater induced stresses on the cycloidal disc. This is because the material content of the disc is reduced.

The tooth profile of cycloidal gears is based on the involute of a circle. An involute is a point that rolls on a circle’s circumference, such as the end of a string unwrapped from a cylinder. Cycloidal gears feature the same outer rolling circle for all gear teeth. A cycloidal gear tooth is thus stronger than its counterpart. Cycloidal gears have an increased strength in low-to-medium-speed applications because there are fewer teeth, such as in clocks. In addition, cycloidal gears have excellent shock load capacity and torsional stiffness.

## Output torque

The output torque of a cycloidal gearbox can vary significantly owing to the resonant characteristics of its components. This article analyzes the effect of torque ripple on the output shaft of a cycloidal gearbox. Numerical simulations were conducted with the help of multibody dynamic software and a mix of rigid and flexible elements. The results were compared with experimental results to identify the influence of the different design parameters on torque ripple. A dynamic model was also introduced to determine the periodical change in the stiffness of the gears and the associated torque ripple.

There are various designs for cycloidal gearboxes. One type of cycloidal gearbox is called a ring gear. The input shaft rotates in an eccentric motion with the ring gear. The cycloidal disc has lobes similar to the teeth of a stationary ring gear. The output disc has roller pins that protrude through the disc. The output disc then transfers the motion to the output shaft.