Nexen's Harmonic Gearhead Delivers Zero-Backlash Motion Control

Dave Hein readily admits that not all manufacturing applications require zero-backlash motion control.

But for those applications that do, the new harmonic gearhead "is an optimal solution."

"Any machine that has either a rotary or linear-motion control function could be a candidate for Nexen's technology," says Hein, who is vice president of engineering for Vadnais Heights, Minn.-based Nexen Group Inc.

There's a compelling case to be made for using the harmonic gearhead, which Nexen developed to complement its lineup of roller-pinion systems.

"The elimination of backlash is key for increasing performance in many applications," Hein tells New Equipment Digest.

NED: What motivated Nexen to develop this product?

DH: Nexen developed the harmonic gearhead to complement its existing roller-pinion technology.

By adding the harmonic gearhead to the roller pinion, Nexen is able to maintain zero-backlash motion control from the servomotor through to the driven load. The elimination of backlash is key for increasing performance in many applications.

NED: How is this product different from similar devices on the market today?

DH: Nexen has packaged class-leading cross-roller-bearing, flexible-coupling and harmonic-drive technology in a form factor that maintains high overall system stiffness with a small physical footprint.

The patented coplanar and concentric design maximizes the torque-to-physical-size ratio.

NED: What problems needed to be addressed during the development process?

DH: The problems encountered during development revolved around testing of the gearheads.

At Nexen, we believe in testing products just like our customers would use them. That means developing test stands that are configured not just structurally, but performance-wise, as our customers' machines.

To support our test efforts, Nexen test engineers developed four test axes with each axis subjecting the gearhead to a different operating condition. We believe this testing contributed to a better end product and gives us confidence working with our customers on new applications.

NED: How long did it take from conception to ultimate production?

DH: At Nexen, we believe 90 percent of what you learn regarding new products is discovered during the first 24 hours of testing. Therefore, we put a lot of energy into quickly developing the first prototype, which allows us to learn and iterate if necessary.

Using this approach, Nexen engineers went from a clean sheet of paper to the first prototype in five months.

NED: What effect did cost factors have in changing the final design of the product?

DH: Cost is always a major factor in the final design of a product. Nexen engineers balance the cost of the components incorporated into a design with the performance of those items, and strive to maximize the value proposition of the balance achieved between high performance and market price.

NED: Who is your target audience and what benefits will they achieve from using this product?

DH: The target audience is very wide and diverse. Any machine that has either a rotary or linear-motion control function could be a candidate for Nexen's technology.

Not all applications require high-precision, zero-backlash motion control. For those that do, Nexen is an optimal solution.

NED: Do you have any other interesting information that you would like to add?

DH: At Nexen, we believe there is only one company in the world that can offer zero-backlash motion control from the driven servomotor through to the driven load. That company is Nexen.