abstract:The harmonic drive gearbox is famous for its ability to deliver precision motion control with very l...
The harmonic drive gearbox is famous for its ability to deliver precision motion control with very low or even zero backlash or vibration. This means it can provide high reduction ratios through concentric shafts in a lightweight yet durable assembly. If you’re looking for the best harmonic drive system supplier in China, you’re in luck! Here at Arcsec Drive, we only sell top-quality harmonic drives.
Harmonic Drive Advantages
The Harmonic Drive system is also known as harmonic drive gear, harmonic drive, or strain wave gearing. It was invented in the 1950s to reduce the gear ratio of a rotary machine to increase torque. There are a number of advantages to using a harmonic drive, including:
It’s a Smartly Designed Concept
Harmonic Drives consist of three concentrically mounted generators:
Wave Generator – this is an elliptical-shaped hub that acts as a link with two rollers. The wave generator rotates within the flex spline, causing it to mesh with the outer circular spline progressively at diametrically opposite points.
Flex Spline – this is a thin-walled, flexible steel cylinder with external gear teeth machined into its outer layer near the ‘brim’ of the cup where the wave generator is inserted. If the wave generator rotates clockwise, the flex spline rotates or rolls inside the circular spline at a much slower rate in a counter-clockwise direction, resulting in more pulling power.
Circular Spline – this is the rigid ring with internal teeth. It engages the teeth of the flex spline across the major axis of the wave generator.
The three basic elements of the design work in harmony and can produce more force in a smaller unit than traditional gear mechanisms. The harmonic drive system is used across a wide range of applications, for example, in milling, manufacturing, and machines that use robotic arms.
Harmonic drive systems have also been employed in a variety of applications, from vending machines to highly sophisticated systems for military and aerospace use.
A unique and useful characteristic of the harmonic drive is its ability to transmit motion through sealed walls. The flex spline teeth can be placed near the centre of a long-hermetically sealed flexible tube. The wave generator can be inside the tube and can deflect the flex spline to produce a slow rotation of the encircling circular spline to increase output torque.
Wider Deceleration Range
The deceleration range of the harmonic drive is wider and can be used in the manufacturing processes of many products. This equipment has more practical advantages over traditional gear systems and can better and more effectively help enterprises control costs.
Compared with other types of gears, the harmonic drive can offer higher degrees of accuracy, which can help improve machinery’s performance. Use of the harmonic drive can deliver higher levels of accuracy, setting your products apart from those of your competitors.
Longer Service Life
The manufacturing process used to produce harmonic drive systems is highly sophisticated, involving the use of advanced technology. This not only ensures the equipment is high-performing but also improves the service life of the equipment. While there is an upfront financial investment to be made, the harmonic drive gear system will pay for itself over time.
Because harmonic drive gears are reversible, they can be back driven. If necessary, loads can be held in place by braking the Wave Generator when the servo system is not powered.
Because power is transmitted by means of multiple tooth engagement, the gear is capable of offering a high output torque capacity which easily equals drives that are twice its size and three times its weight.
The operating efficiency of the harmonic drive can reach up to 90%. These ratings are based on actual shaft-to-shaft tests.
Overall, the harmonic drive system maximises torque output in units that are much smaller and lighter than other types of gear systems. There are plenty of benefits to be gained, as noted above, and it is a highly versatile gear system that has many applications across a wide range of industries and can help companies cut costs where it is used.
Harmonic Drive Applications
Harmonic drive can be used in any gear reduction application 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 machines, milling and lathe machines, flexo-printing machines, semiconductor equipment, optical measuring machines, woodworking machines, and camera head pans tilt axes. Some of the most notable applications for this system were in the wheels of the Apollo Lunar Rover and the winches of the Skylab Space Station.
Harmonic drive prices are driven by the quality and how the system will be used in various types of machinery. If you would like further information or want to enquire about the pricing of our harmonic drive gearboxes, feel free to get in touch today.
The Benefits of Harmonic Drives
The harmonic drive design provides more advantages than just speed reduction. The teeth of a harmonic drive engage in such a way that approximately 30% of them are meshed at any one time, and exactly half of those engaging at any time are at 180 degrees to the other half (at either end of the ellipse axis). Therefore, pitch errors are corrected. With drives like those from Harmonic Drive, which have single-stage reduction ratios ranging from 30:1 to 320:1, positioning accuracy can be better than a minute of arc and repeatability as little as a few seconds of arc.
The teeth of the flex spline are preloaded against those of the circular spline, and any wear in the teeth is compensated for. The drives work with nearly zero backlash. Friction losses and wear and tear are, at worst, barely perceptible due to the way the teeth come into contact with almost no sliding velocity in an almost pure radial motion.
How Harmonic Drives Work
The rotational movement is driven by a servo motor input shaft, for example. This is connected to a wave generator, an elliptical element encircled by a ball bearing of the same shape. The shaft’s rotation creates an apparent ‘motion wave’ which drives the flex spline, a belt constructed from a flexible yet torsionally stiff material. The wave motion is taken up by the material, which flexes in response to the input shaft’s rotation and generates an elliptical form. The flex spline is positioned inside a circular spline, a round, fixed gear with internal teeth. The former has fewer teeth than the latter, so when the teeth of the flex spline and the circular spine mesh, the flex spline rotates by a small degree in the opposite direction and at a much-reduced ratio. The gear teeth on the outer edge of this flex spline are capable of transferring high weights without difficulty.
The Characteristics of Harmonic Drives
Here are just a few of the characteristics of harmonic drives:
High-speed reduction ratio
The strain wave transmission system has single-stage coaxial reduction ratios of 1/30 to 1/320, making it ideal for high-efficiency gearing.
Backlash-free (lost motion)
The harmonic drive differs from conventional tooth-to-tooth mating in that it uses little backlash (nearly zero), which is an important feature for motion control.
With harmonic drive gearboxes, high positional and rotational accuracy is guaranteed because a substantial number of its teeth are always meshed and engaged at two regions 180 degrees apart, which eliminates tooth pitch mistakes and accumulated pitch errors on rotation.
Small number of components and ease of assembly
The harmonic drive consists only of three key parts, all of which are co-axially aligned, meaning it is easy to integrate it into component-assembled machines for easy configurations.
To learn more about this innovative mechanical speed-changing device and the benefits of harmonic drive gear systems, get in touch with us today. We are always happy to discuss our products.