Strain wave gear improve performance compared to traditional gearing systems.

Leaderdrive is trademarked by Leader precision drive.

They are typically used in industrial motion control, machine tool, printing machine, robotics and aerospace.

Application in aerospace: they are used in satellite for proper orientation of solar panels towards sun, It was first used in space during Apollo 15 mission.

Application in Robotics and Automation: They are used for handling of tasks particularly “pick and place”.

Application in Defence: They are used in Remote Weapon Station (RWS). RWS is renotely operated.

Strain wave gearing is a special type of mechanical gear system whose theory is based on elastic dynamics and utilizes flexibility of metals.

The three basic components:

1. Wave Generator (Input)

2. Flex Spline (Output)

3. Circular Spline

Wave Generator is made of two separate parts:

1. Elliptical disk called wave generator plug

2. Outer ball bearing

Flex Spline

1. Flex Spline is like shallow cup. The sides of the spline are very thin but the bottom is thick and rigid.

2. Teeth are positioned radially around the outside of the flex spline.

3. The flex spline fits tightly over the wave generator, so that when the wave generator plug is rotated. The flex spline deforms to the shape of a rotating ellipse.

Circular Spline

1. The circular spline is rigid circular ring with teeth on the inside.

2. The flex spline and wave generator are placed inside the circular spline, meshing the teeth of the flex spline and the circular spline.

3. Because the flex spline has an elliptical shape, its teeth only actually mesh with the teeth of the circular spline in tow regions on opposite sides of he flex spline, aling the major axis of the ellipse.

Working

1. Assume that the wave generator is the input rotation.

2. As the wave generator plug rotates, the flex spline teeth which are meshed with those of the circular spline change.

3. The major axis of the flex spline actually rotates with wave generator, so the points where the teeth mesh revolve around the centre point at the same rate as the wave generator.

4. The key to the design of the strain wave gear is that there are fewer teeth (fro example tow fewer) on the flex spline than there are on the circular spline.

5. This means that for every full rotation of the wave generator, the flex spline would be required to rotate a slight amount (two teeth, for example) backward relative to the circular spline

6. Thus the rotation action of the wave generator results in a much slower rotation fo the flex spline in the opposite direction.

For strain wave gearing mechanism the gearing reduction ratio can be calculated as follows:

Reduction Ratio = (Flex Spline Teeth–Circular Spline Teeth) Flex spline Teeth For example, if there are 202 teeth on the circular spline and 200 on the flex spline, the reduction ratio is (200 − 202)/200 = −0.01 Thus the flex spline spins at 1/100 the speed of the wave generator plug and in the opposite direction.