Gearmotors Pulling, Pushing-and Controlling-Their Weight

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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].

Article Review: Gearmotor Impact of Reflected Mass Inertia From Load?

As originally printed in MotionControlTips.com January 10, 2019, by Miles Budimir with updated March 1, 2019 content.

In any drive system (that is, a motor driving a load), there is going to be inertia. Specifically, the motor will have inertia as will the load. For a direct drive system (a direct motor-to-load connection) the individual inertias can just be added together in a straightforward way. However, for any other type of setup involving some additional mechanical drive components such as couplings or gears, the relationship changes.

 

The inertia of the gear train, as well as any elements of the motor connection system itself, will also need to be considered. Leaving these inertia values out of the overall calculation produces an incorrect value for overall inertia and can lead to under-sizing input torque requirements.

What’s missing from the total system inertia is the inertia of the gears themselves and any other components of the connection system such as couplings. Another factor to keep in mind is that even with the same ratio different types of speed reduction and couplings may have different inertia values.

The key point is this: If the gear reducer is added separately, then the inertia value of the gears (usually provided by the manufacturer) needs to be added into the total system inertia. However, when purchasing a complete gearmotor, check with the manufacturer to determine if the published gearmotor inertia value includes the inertia of the internal gear reducer.

The bottom line is when calculating the total inertia for any motion system, the final value must include the inertia of all rotating parts, including the drive (such as a belt and pulley system, screw, or rack and pinion, etc.), the load being moved, the motor, the gearbox (if used in the system) and the coupling between the load and the motor.

When looking at how gears impact a drive system’s inertia, there are some basic ways to look at it. The basics; any gear will reduce the load inertia reflected to the motor by a factor of the square of the gear ratio. When looking at a gearmotor, this is basically just a motor with an embedded gearset in it, so the calculations and formulas for calculating inertia are the same.

In high-performance motion control applications, it’s ideal for the reflected load inertia to equal the motor inertia. If inertia matching is the only concern, then the gear ratio can be calculated as:

N = √ (JLoad/ J Motor)

where N is the gear ratio, JLoad is the inertia of the driven load, and JMotor is the inertia of the motor.

Note: Another way to calculate gear ratio is by reference to the individual gears. For instance, if NIn is the number of gear teeth on the input gear and NOut is the number of gear teeth on the output gear, the gear ratio is then:

N = NOut / NIn

As for reflected inertia itself, this is best understood as the inertia of the load that is translated back to the motor through various drive components, in this case, the gearing of the gearmotor.

So in a simple direct-drive system, the total inertia would be calculated like this:

JTotal = JLoad + JMotor

However, for a geared drive system such as a gearmotor, the total inertia is calculated using the equation:

JTotal = ( JLoad / N2 ) + JMotor

This is because, as stated earlier, the reflected load inertia is equal to the load inertia divided by the square of the gear ratio.

For additional gearmotor content, go to MotionControlTips.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].

The New GHX 250 – Doubling Service Life & Higher Protection Class

The New “GHX 250”: Doubling Service Life & Higher Protection Class 

With constant market observation ABM Drives, Inc. proactively develops and optimizes drive systems to maximize the benefits for customers and their projects. We are excited to present our new GHX 250 in protection class IP65: the GHX 250 excels with twice the service life, high efficiency as well as outstanding performance.

Powerful & DurableHoist Drive Unit GHX 250

GHX 250 – Product Highlights

    • Interface (Output shaft & Mounting) remain unchanged
      • GHX 250 will be 100% interchangeable with the existing GH 25000 & GH 25001
    • Enhanced possible field of application due to extended center distance
      • Installation of drum sizes up to 405 mm
    • Consequent classification of FEM 2m at all drum sizes at reeving 4:1
      • Doubling their service life
    • Increased speed up to 200 Hz (motor) in no-load condition for VFD version
      • Reduction of cycle time
    • Enhanced switching behavior in two-speed version
      • Reduced noise
    • Higher protection class IP65

GHX 250 Changeover Schedule

    • Samples for the GHX 250 can be ordered from August 2019.
    • Series-production starting in November 2019.
    • Replacement motors and spare parts will remain available for all existing GH 25000 & GH 25001 drives.

Product information will give you further details on the GHX 250 and its many benefits. Click the link below to access the:
New GHX 250 ABM NA Brochure

ABM Drives - Hoist Drive Unit GHX 250


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].

Gearbox and Electric Motor Drive Units for Forklifts

TDF230 ABM Greiffenberger Compact Gearbox & Electric Motor

‘Your Vision is our Drive’

ABM Greiffenberger develops efficient forklift drives for traction, lifting and steering for its customers. As a system supplier the company from the Upper Franconian town of Marktredwitz offers all drive components from a single source. TDB series bevel gears and TDF series parallel shaft gears were some of the products that could be seen at LogiMAT. They are powerful, energy-saving and reliable in daily use.

Fast movement and smooth transport of goods in various sizes and weights are important factors in intralogistics. Accordingly there are also high demands on the drive technology. Gearboxes from ABM Greiffenberger feature impressive driving comfort and safety. They meet strict environmental and emission requirements. In the expanding electrification, that amongst other benefits provides noise reduction in storage and warehouse uses, the company sees further growth in market potential.

The gearbox solutions from ABM make high gradeability and acceleration of pallet trucks possible. Even at low speeds forklifts can be controlled precisely – with highly dynamic steering. Thus operators can maneuver them more easily, even in tight spaces. ABM offers ready-to-install plug-and-play systems which are available in modular form according to a platform concept. Motor, gearbox and sensors can easily be integrated into different vehicle types.

TDB series bevel gears can be used for a variety of purposes.

TDB230_254_Kombi_ABM Greiffenberger Compact Gearbox and Electric Motor

Figure 1: Type TDB 230/254 Kombi bevel gears from ABM Greiffenberger can be used for wheel diameters of 230 and 254 mm.

They are found in reach trucks, tow tractors, autonomous transport systems and sweepers/scrubbers. The components are powerful and highly efficient. Even with small batteries, users can work reliably for long periods. The TDB series was extended with a drive that can handle output torques up to 750 Nm. With an unchanged installation space, the drive torque was once again increased by 15% over the predecessor model. ABM Greiffenberger designed the series to be compact. The vertical motor mounting and the further optimization of gearbox components such as gearing and housing lead to a small envelope circle: the user benefits from a space saving gearbox installation.

ABM Greiffenberger developed the bevel gearboxes for wheel diameters of 230 and 254 mm and a wide range of applications and great flexibility: application-specific combinations of gear ratio and motor output can be easily realized. The series is also available in combination with an integrated steering drive and redundant steering monitoring right on the drive wheel. For ‘driving’ ABM offers temperature monitoring via a temperature sensor. Motor speed recording is done via an incremental encoder with up to 64 pulses per revolution. Use of a regenerative AC technology is also possible. An electromechanical holding brake takes care of parking and emergency stopping. The overall design thus offers a wide variety of functions and combination options. Now both developers of customized individual applications and OEM project managers for cross-fleet platforms have the ideal drive for their respective application available.

TDF series: Quiet Running and Plenty of Power

TDF230 ABM Greiffenberger Compact Gearbox & Electric Motor
Figure 2: The high-contact-ratio helical gear technology used in the TDF parallel shaft gear series from ABM Greiffenberger guarantees maximum efficiency and quiet running.

TDF series parallel shaft gears impress through their high efficiency, quiet running and longevity. Especially quiet running is stressed over and over by users. This is made possible by the highly optimized helical gear technology used by ABM Greiffenberger. The gearboxes are suitable for use in pallet trucks and three-wheel sit down forklifts, amongst others. The die-cast aluminum alloy housings used with sizes 200 and 230 mm ensures lightness, high stability and corrosion resistance. The housings for versions with wheel diameters 254 and 471 mm are are made out of robust ductile iron.

ABM offers the TDF series with a motor output of 1.2 to 4.7 kW. The maximum wheel torques range from 435 to 1,400 Nm. The gears can be supplied with different gear reductions based on the applications. ABM Greiffenberger can develop customer-specific housings for a cross-fleet platform design and large vehicle volumes. Even with the TDF series, precise motor speed recording for smooth deployment is possible.

System supplier with high-level development expertise

With the trade fair presentation, the drive specialist displayed its strengths as a system supplier with a high level of consultation and development expertise. It supplies all products, both motors and gearboxes, from a single source. With additive manufacturing even complex prototypes can be quickly produced. Modern testing technologies, motor dynos and a laboratory for materials analysis ensure high quality in design and engineering already at the development stage. With its in-house aluminium die-casting foundry, the company has attained a prominent position in the production of gearbox housings. The parts are produced with high process reliability on automated and flexible machines and machining centres. Robot-controlled manufacturing cells and winding lines enable consistent series quality.

ABM Greiffenberger has always paid special attention to ensuring close customer relationships and intense market monitoring. Based on its modular and extensive portfolio, the drive specialist develops application-tailored space- and cost-optimised systems with maximum benefit to the user.


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].

The Importance of Product Design

By Bradford L. Goldense, Contributing Technical Expert, MACHINE DESIGN Magazine, Jan 24, 2019.

(Thanks for the great article, “The Importance of Product Design.” This along with the article about digital twins, “How Does One Get Started with PLM and the Digital Twin?” made for a good February 2019 issue.)

When was product design not important? Product design has always been important. It is almost a law of nature. When was quality not important? This too is practically a law of nature. The elevation of both areas began back in the 1980s. For industrial design, service firms such as Design Continuum, IDEO, and a couple-dozen others formed into an industry as enabling 3D and surface design technologies also came of age. And user-interface (UI) engineering began its related roots as electronic devices emerged. For product quality, first Deming, Juran, Crosby, and others brought great techniques. Then came Jack Welch at GE, and Six Sigma spread widely a decade later. Currently, factors indicate that the competencies of product design are on the way to their next heyday. Several new groups of design requirements are converging in the same timeframe.

3D Printing & Additive Manufacturing Options: 3D printing emerged in the late 1980s and has been maturing for three decades. In 2018, it turned the corner to also become a production technology. BMW, Audi, Boeing, GE, Stryker, and others started using additively manufactured production parts. Hooray for 3D, but the challenges just grew for designers. Many more important decisions should now be made earlier. As a prototyping tool, manufacturing decisions could wait. But as a production-design tool, all the responsibilities of production design should be taken on if minimizing time-to-market is a goal. Designers also face increased choices when deciding how best to create production parts and assemblies with now six types of manufacturing processes to choose from (MDSep ’18). The choices directly affect product cost and profitability.

IIoT- & IoT-Enabled Products: Designers are increasingly having to “sensorize” products that will be manufactured in an industrial internet environment. As automated production grows, designs must progressively provide for transmitting data back and forthwith factory equipment during manufacture (MD Apr ’17). Materials, finishes, coatings, and other external and surface design trade-offs are becoming more complex to balance the needs of GD&T, inspection, and testing, with industrial internet sensing and interactivity. Further, designs must increasingly accommodate an array of sensors to maximize the value of information attained after the product leaves the factory and engages the IoT in the customer’s environment (MD Nov 16). Many corporations are repositioning their product strategy so that the value of the data collected by sensors in IoT-enabled products will eventually overtake the value of the physical product itself.

Industrial & UI Design Needs: The importance of product appearance and the desire of owners to customize interfaces have been growing steadily for a dozen years. Apple’s launch of the iPhone raised the bar and fueled the next great wave of UI design. It didn’t take a wizard to see that good UI design increased revenues and profits. UIs are just part of the overall product design, however. UI real estate requirements get traded off against total real estate, which is the larger subject of industrial design. With most products being sold globally, threading the needle on an industrial (and UI) design that is globally appealing is critical. Recently, corporations and researchers began examining the extent to which good industrial design also affects the top and bottom lines. The impact on revenues and profits is greater than previously thought. A UK study found good designs also increased exports by 5% (MD Apr ’16).

Environmental, Materials, Miniaturization: Environmental design considerations have been growing steadily, and they increasingly differ by country and region. Design for Environment, Design for Disassembly, Design for Recyclability, and other eco-sphere DFX approaches are evolving. Not counting the many new 3D printing materials and metals, materials available to designers for all types of manufacturing processes are also growing. Then, on the horizon, is a new wave of miniaturization as MEMS and nano components come of age.

Future Product Design Masters: In the future, the best product designers will have mastered the numerous ways of blending appearance, usability, and functionality, with increasingly smaller earth-friendly capabilities and data sciences that enable the majority of the product’s value to be realized after it has left the building.