Calculation of Reduction Ratio in a Cycloidal Gearbox

The reduction ratio in a cycloidal gearbox can be calculated using the following formula:

Reduction Ratio = (Number of Input Pins + Number of Output Pins) / Number of Output Pins

In a cycloidal gearbox, the input pins engage with the lobes of the cam disc, while the output pins are engaged with the cycloidal pins of the output rotor. The reduction ratio determines the relationship between the number of input and output pins engaged at any given time.

For example, if a cycloidal gearbox has 7 input pins and 14 output pins engaged, the reduction ratio would be:

Reduction Ratio = (7 + 14) / 14 = 1.5

This means that for every 1 revolution of the input pins, the output rotor will complete 1.5 revolutions. The reduction ratio is a key parameter that influences the output speed and torque of the cycloidal gearbox.

Patents Associated with Cycloidal Gearbox Designs

Throughout the history of cycloidal gearbox development, several patents have been filed for various designs and applications. Some notable patents include:

• Harmonic Drive: Ralph B. Heath’s patent for the “Harmonic Drive” (US Patent 2,906,143), filed in 1957, is one of the most famous patents related to cycloidal gear systems. This patent introduced the concept of a high-precision reduction gear mechanism using flexible components.
• Cycloidal Drive Mechanism: A patent by James Watt for a “Cycloidal Drive Mechanism” (GB Patent 1812), dating back to the 18th century, is often cited as one of the early references to cycloidal motion and gears.
• Planetary Roller Transmission: US Patent 3,671,927 by C.F. Kafesjian and H. Blumenstock introduced a “Planetary Roller Transmission” in 1972, describing a cycloidal drive mechanism with planetary motion.
• Cycloidal Speed Reducer: A patent for a “Cycloidal Speed Reducer” (US Patent 5,588,583) was granted to Richard J. Pieprzak in 1996, focusing on an improved design of cycloidal gears for various applications.

These patents represent a small sample of the numerous innovations and designs related to cycloidal gear systems that have been patented over the years. Patents play a significant role in protecting and promoting innovation in the field of gearbox technology.

Principle of Cycloidal Gearing

Cycloidal gearing is a mechanism that utilizes the unique shape of cycloidal discs to achieve motion transmission. The principle involves the interaction between two main components: the input disc and the output disc.

The input disc has lobes with pins, while the output disc has lobes with matching holes. The lobes on both discs are not perfectly circular but are shaped in a cycloidal profile. As the input disc rotates, the pins on its lobes engage with the holes in the output disc’s lobes.

As the input disc rotates, the pins move along the cycloidal paths, causing the output disc to rotate. The interaction between the pins and the holes results in smooth and continuous motion transfer. The unique shape of the cycloidal profile ensures that there is always at least one point of contact between the pins and the holes, allowing for efficient torque transmission and reduced wear.

Cycloidal gearing provides advantages such as high torque capacity, compact size, and precision motion. However, due to the complex shape of the components and the continuous engagement, manufacturing and assembly of cycloidal gearboxes can be intricate.

editor by CX 2023-10-23