How will a Harmonic Drive function? Why are they utilized?

Among the many benefits of a harmonic drive may be the lack of backlash due to the unique style. However, the fact that they are light-weight and extremely compact can be important.
High gear reduction ratios of up to 30 occasions that achieved with planetary gears are feasible in the same space.
C W Musser designed strain wave gearing back 1957 and by 1960 he had been selling licenses so that industry giants might use his patented item.
harmonic drive assembled The harmonic drive is a type of gear arrangement also known as a strain wave gear because of the way it works. It is a kind of reduction gear mechanism comprising a minimum of three main components. These parts interact in a manner that allows for very high precision reduction ratios that would otherwise require a lot more complex and voluminous mechanisms.

As a product, the harmonic drive was invented by the American engineer Clarence Walton Musser in 1957, and it quickly conquered the industry with the countless advantages that it brought to the desk. Musser discovered the potential of his invention at an early on stage and in 1960 started offering licenses to producers so they might use his patented item. Nowadays, there are just a small number of manufacturers in america, Germany, and Japan who are keeping the license to create harmonic drives, doing this at their top-notch facilities and creating ultimate quality strain gears for the whole world.

harmonic drive exploded viewThe workings of a harmonic drive
The rotational movement originates from an input shaft that can be a servo electric motor axis for instance. This is connected to an element called “wave era” which includes an elliptical form and is definitely encircled by an elliptical ball bearing. As the shaft rotates, the edges transformation position, so it looks like it really is generating a movement wave. This component is inserted in the flex spline that’s made out of a torsionally stiff however flexible materials. The material occupies this wavy motion by flexing according to the rotation of the insight shaft and in addition creates an elliptical shape. The outer edge of this flex spline features equipment teeth that are suitable for transferring high loads without any problem. To transfer these loads, the flex spline is installed in the circular spline which is a round gear featuring internal tooth. This outer ring is definitely rigid and its own internal diameter is marginally larger than the major axis of the ellipse formed by the flex spline. This means that the circular spline does not believe the elliptical form of the other two parts, but rather, it merely meshes its inner teeth with those of the outer flex spline side, leading to the rotation of the flex spline.

The rate of rotation would depend on the rotation of the input shaft and the difference in the amount of teeth between the flex spline and the circular spline. The flex spline has fewer teeth than the circular spline, so that it can rotate at a much reduced ratio and in the opposite direction than that of the input shaft. The reduction ration is distributed by: (amount of flex spline teeth – quantity of circular spline tooth) / number of flex spline tooth. So for example, if the flex spline provides 100 teeth and the circular spline offers 105, the reduction ratio is (100 – 105) / 100 = -0.05 which means that the flex spline ration is -5/100 (minus indicates the opposite direction of spin). The difference in the number of teeth can be changed to support different reduction ratios and thus different specialized wants and requirements.

Advantages
Achieving decrease ratios of 1/100 or more to even 1/300 by simply using such a compact light set up of gears can’t be matched simply by any other gear type.
The harmonic drive is the only gear arrangement that doesn’t feature any backlash or recoil effect, or at least they are negligible used. That is mainly thanks to the elliptical bearing fitted on the external rim of the insight shaft enabling the free rotation of the flex spline.
The positional accuracy of harmonic drives even at an extreme number of repetitions is extraordinary.
Harmonic drives can accommodate both forward and backward rotation with no need to change anything, and they retain the same positional accuracy on both spin directions.
The efficiency of a typical harmonic drive measured on real shaft to shaft studies by the manufacturer goes up to 90%. There are very few mechanical engineering elements that can claim such an operational effectiveness level.
Uses for a harmonic drive
In short a harmonic drive can be utilized “in virtually any gear reduction software where small size, low weight, zero backlash, high precision and high reliability are required”. Examples include aerospace applications, robotics, electric vehicles, medical x-ray and stereotactic devices, milling and lathe machines, flexo-printing machines, semiconductor equipment, optical measuring machines, woodworking devices and camera mind pans and tilt axes. The most notable types of harmonic drive applications are the tires of the Apollo Lunar Rover and the winches of the Skylab space station.