Industrial mainstay adapts to remain relevant in a 4.0 world
As manufacturers wend their way through what is now the increasingly vertical 4.0 world of industry, more of what were once-essential manufacturing components and processes find themselves on the endangered species list.
But not gearmotors. In some industries, they’re becoming more relevant than ever. For example, as more hydraulics-driven applications transition to electronic actuators, gearmotors are taking over. In addition, national defense and automotive are just two major sectors where geared actuators are specified, especially for custom applications. Indeed, if high force is required, gear or ball screw actuators remain the way to go.
This is not to say that gearmotor makers don’t have concerns and conditions to deal with; some very real ones include:
- Growing gearmotor manufacturer and customer cost concerns in light of the escalating China trade war, which will directly affect magnet prices (brush and brushless DC, as well as IPM AC) and commutators (brush DC) — not to mention tariff-related rising steel and aluminum prices.
Looking for more insight, we asked some industry experts for their views on gearmotor usage and continued relevancy.
For instance: what is the relevancy of gearmotors relative to hydraulics used in electronic actuators? Is the needle pointing up or down? What would be their most common industrial application? It depends — as almost always — on the application. Is brute force needed — or motion-controlled finesse?
“Just about every OEM application you can think of is trying to accomplish greater flexibility, precision and efficiency, says John Morehead, principal consultant for Motion Mechatronics. “That’s why there’s a strong move to replace hydraulic actuators with electric motor-driven actuators. Rather than the brute force of a hydraulic motor driving various linkages, the move today is toward distributed motion with individual smaller, more efficient electric gearmotors. A notable example is agricultural precision planting to increase yields and reduce costs for farmers. Not only can the maintenance of a complex system of jackshafts, sprockets and chains be replaced with individual gearmotors; each one can be controlled individually to maximize yield for each row planted, which is important when the multi-row planter turns corners or follows curves. The elimination of hydraulic fluid leaks and contamination is a bonus.
“A wide range (of relevancy), says George Holling, CTO, Rocky Mountain Technologies and Power Transmission Engineering motors blogger. “We are working on missile actuators where size, volume and weight are the prime concerns, and gearmotors do well. Gearmotors now start to match the power density of hydraulic systems on an overall system comparison. The distributed system and the independence between actuators vs. a single hydraulic reservoir add a high level of redundancy and potentially also lower overall system and installation cost, as wires are lighter and cheaper to install than hydraulic lines.”
Looking for more, we asked about the efficacy of gearmotors/actuators in, for example, fly-by-wire and drive-by-wire applications requiring high power densities.
Holling responds that “The total efficiency is the actuator efficiency * gear efficiency. As motor speed increases, the motor efficiency will increase — especially p to 2KRPM-3KRPM at higher speeds it will drop again. Gear efficiency is approximately 90%; most gear ratios are 3:1 to 6:1.”
Morehead believes that “High-power density brushless DC gearmotors, combined with optimized efficiency gearing, is becoming the standard in autonomous warehouse robots. Brushless DC is not only more responsive but also more efficient and compact, with virtually limitless lifetime expectations compared to conventional brush DC gearmotors.”
Returning to automotive applications, is it relevant to wonder what, if any, part gearmotors play in electric vehicles? To what extent do potentially deal-breaking things like size, weight and gear cost apply?
“EV motors typically have a fixed reduction gear to reduce the motor size,” Holling states. “Increasingly, OEMs are looking to increase the motor speed to 12KRPM or more to save motor cost. There will be an optimal point where the total cost of motor + gear is minimized.”
And what of any advances of note in plastic-geared gearmotors/drive systems? Available information is a bit sketchy, but Holling reports that he’s “seen a durable, plastic-based gear system out of China: lightweight, low cost and somewhat durable. And we know of at least one Chinese manufacturer that integrated a plastic gear into a traction motor for small 3-wheel delivery trucks. I do not know if this panned out though.”
China’s mention returns us to the tariffs/trade war issue. Sure, it is all very political and perhaps uniquely Trumpian, but this is a “guns-and-butter,” all-hands-on-deck issue for certain manufacturers — like those of gearmotors.
Morehead allows that “Unexpected tariff burdens are a fact of life today, where gearmotors possess content sourced from China and has prompted U.S. gearmotor manufacturers to look toward other low-labor-cost APAC (Asian-Pacific) countries for component or motor sourcing. Of course, the warning signs have been there for years and basic global economics foretell that the advantages of low labor and material costs are fleeting as economies develop. If all you make today is a standard-design gearmotor, you’ve set yourself up for global commoditization.
“While it’s more important today than ever to provide the best application and design engineering support, along with highest quality and shortest lead times, it is becoming evident that customers are looking for more than just a gearmotor. Those gearmotor manufacturers who can also provide motor controls, cabling, brakes, encoders, brackets, shielding, enclosures and anything else customers will find advantageous to purchase as a sub-assembly will be rewarded with a stronger customer relationship and increased insulation from competition.”
For Holling, in much the same vein, “These motors are becoming a commodity item with shrinking margins and strong price competition from China and others, which makes them less attractive to U.S. producers,” says Holling. “Unless the supplier can offer a value-added which commands better margins, the U.S. is not competitive.”
Meanwhile, seemingly, everything is a moving target in today’s automated, bot-driven world. And highly sophisticated, software-driven motion control is now manufacturing’s meat du jour. So where do, say, brushless DC motors fit in?
“Integrating the control required to make the brushless motor turn with the motor only makes sense in terms of eliminating costs of cabling and enclosures, while simultaneously eliminating electrical interference issues,” says Morehead. “In addition, the OEM’s installation time and cost are reduced and field servicing, which is always a burden, is greatly simplified. The OEM’s greatest source of frustration is when a motor-and-drive problem arises and they’re faced with finger-pointing from two separate sources. Simple speed controls are just the first step and the gearmotor manufacturer’s controls capability needs to eventually expand to positioning and networking to ensure being able to offer the highest-value, differentiated gearmotor solutions.”
Holling explains that “Integrated controls can simplify the machine design, wiring costs etc. Thus, an integrated controller is a prime example of a value-added service that customers value and pay for. An integrated controller can also reduce design time and cost for equipment. Allow for future upgrades and field replacements (repair with different or generic components), and the reduced wiring and connections can potentially improve reliability.”
“These motors are becoming a commodity item with shrinking margins and strong price competition from China and others, which makes them less attractive to U.S. producers,” Holling says. “Unless the supplier can offer a value-added which commands better margins, the U.S. is not competitive.”
For additional gearmotor content, go to PowerTransmission.com
Choosing a Gearbox Drive and Electric Motor Supplier
When choosing manufacturing partners during a machine build, remember that there are two methods for choosing a gearbox and electric motor supplier. One is selecting a pre-engineered unit and the other is choosing a gearbox-motor combination and integrating them into the equipment.
Pre-engineered gearmotor solutions are suitable if a design engineer doesn’t have the time or engineering resources to build a gearmotor in-house — or if the design needs a quick setup. New modular approaches to support OEMs (and enable new machine tools, automation, and design software) now let engineers get reasonably priced gearmotors even in modest volumes.
It’s true that one benefit to selecting a separate motor and gearbox and then combining them can less expensive than choosing a pre-engineered gearmotor. Another benefit to this approach is that one may be able to design the most optimized gearmotor for the application at hand … because this approach also gives the design engineer the most control over the final configuration and cost.
No matter the approach to gearmotor selection, be sure to continually improve the design by comparing predictions of performance with measurements. Then use the result of the analysis to improve next gearmotor iteration.
Contact: Gabriel Venzin, President, ABM DRIVES INC, +1-513-576-1300, [email protected].
