By James Sawyer
During the last five years, the gear manufacturing industry could be likened to the cars so many of its products find their way into: either they’re cruising along in Drive, or they’re idling in Neutral. What state gear generation finds itself in at a given time can be attributed in large part to the condition automaking is in, although a number of other industries have an impact as well.
As those in the gear-generation segment load up their own vehicles and head to McCormick Place, the mood is more upbeat than it was the last two times IMTS was held. In many respects the auto industry is responsible. Vehicle sales have climbed steadily (if sometimes slowly) from the trough they were in a few years back. More vehicles mean more gears in transmissions, on engines, in differentials, and so forth.
There is also a trend to vehicle transmissions with more speeds. While a four- or five-speed automatic transmission was once the norm, six-, seven-, even eight-speed transmissions are on the market now. Upcoming fuel economy standards will result in transmissions with yet more speeds in the future. Such regulatory demands are also having an effect on the types of gears being made.
Concerned with Capacity and Noise
With profile and generating grinding, according to Andreas Mehr, Liebherr-Verzahntechnik GmbH (Kempten, Germany), today most gear manufacturers need the ability to create high-quality gear flanks with special topological modifications. "With these modifications, it is possible to increase the load-carrying capacity of gears, and also to reduce the gear noise behavior," Mehr says. He sees this trend taking place in all gears, from the small module gears used in automotive to the larger ones used in trucks and tractors, and even up to the coarse-pitch applications for wind energy and heavy industrial transmissions.
He goes on to say that "if you can grind these topological gears more efficiently, for example with dressable CBN tools, or generate grinding of large module, instead of profile grinding, then these customers will have a big productivity advantage over their competition."
Scott Yoders, VP of sales at Liebherr Gear Technology Inc. (Saline, MI) points out the effects of another trend. The need for chamfering and deburring of gears in the green manufacturing process chain has led to innovative "integrated chamfering and deburring systems" within gear hobbing machines.
"In this regard," he says, "years ago Liebherr—together with the cutting tool company LMT-Fette—introduced ChamferCut-Technology to industrial mass- and medium-size production applications. Recently these integrated chamfering systems within the LC-gear hobbing machines have been expanded upon by Liebherr to include separate ‘parallel-processing’ stations such as Rausch-Gratomat, or roll-press deburring. Within the same machine, and with the parallel-processing, the total cycle time for both hobbing and chamfering is not increased."
Investment Feeds Productivity
"For coarse pitch gear applications," he continues, "carbide indexable inserted tools—milling cutters and hobs—have definitely gained more and more importance in North America. Although gear manufacturers’ initial investment in hob cutting tools is higher, the productivity due to larger batch sizes is much better, so it pays off."
Liebherr will be exhibiting ithe LFG 1000, a new gear profile-grinding machine, and the LSC 500 gear generating- and profile-grinding machine.
Alan R. Finegan, director, marketing at Gleason Corp., takes a true big-picture approach in describing the source of innovation in the gear generation field. "The trends driving innovation in the gear industry," he says, "are probably no different than the trends driving most metalworking industries, and that is the customer’s need for higher quality, more flexibility, lower costs, and when investing in plant and equipment, lower TCO—total cost of ownership. Innovations in processes, equipment, tooling or software that do not address one or more of these issues are probably not valued by the market.
"Obviously, the end users determine the required quality levels and the acceptable cost levels to achieve quality while remaining competitive in their markets."
By the time the next IMTS is held in 2014, Finegan says, "We see no major changes but rather a continuing evolution of the trends that exist today, including greater globalization and an increasing emphasis on lower TCO. Two years is not a long period of time for change in manufacturing processes, particularly those involved with metalworking. What may change is the end-user markets and the applications themselves.
"Automotive markets, for example, are driven by quality and cost, but also by fuel efficiency mandates, which in turn drive transmission design, which drives changes in the number, type, size and quality levels of gears."
As for IMTS 2012, according to Finegan, "Gleason’s mission is to be the total gear solutions provider. As such, we have the broadest array of processes, products and services in the industry and the broadest geographic coverage in the world. At IMTS we will be presenting new processes, machines and tools that address the issues of quality, cost, flexibility and total cost of ownership, that further establishes our company as a leader within our industry for gearing of all sizes, types and applications."
The Quest for Quiet Continues
EMAG LLC is located in the Detroit suburb of Farmington Hills, MI, in order to be close to one of the key industries it serves—automotive. Such proximity necessarily gives the company insight into that industry’s plans and needs, among them the trend toward battery-powered vehicles.
"If you can grind these topological gears more efficiently, then these customers will have a big productivity advantage over their competition."
According to Peter Loetzner, CEO of EMAG LLC, "The industry will be required to develop quieter gears and transmissions if the trend of electric-drive technology continues since transmission noise will be audible with the reduced or even totally eliminated noise from an internal combustion engine." He also believes that improvements in gear manufacturing spurred by electric vehicles will also benefit traditional gasoline-powered vehicles and that the trend to more speeds in vehicle transmissions will continue "to nine-speed and maybe 10-speed transmissions with a double-clutch design."
He also believes that the windpower market for gears, "which has helped many manufacturers to carry through the recession," will most likely scale back due to a falloff in government subsidies.
As for his company’s focus at IMTS, Loetzner says it will be on the launch of the VL 2 P, a vertical turning production center, equipped with two spindles and pendulum technology to increase precision and efficiency for workpieces that have a diameter of up to 100 mm. "With its groundbreaking new technology," he says, "the VL 2 P has almost eliminated its nonproductive times due to loading and unloading." EMAG will also display technology that allows manufacturing of "noise-reduced gears" using advanced electrochemical machining technologies for higher precision and smoother finishes.
A Holistic Approach
At the booth of Star SU LLC (Hoffman Estates, IL), President David Goodfellow says, attendees will find a holistic approach to gear making. "Improvements in gear manufacturing come from the ability to understand machines, tools and application as a completely integrated process. Star SU’s focus will be to showcase our ability to offer this complete integration of machines, tooling, applications and services from a single source."
Accuracy, he contends, is one of those improvements that is becoming more widespread.
"In the past," states Goodfellow, "gears ground for accuracy were prevalent in aerospace, turbine, and with marine propulsion gears. With the onset of eight- and nine-speed transmissions running at much higher rpm, power density and sound issues have the automotive manufacturers calling for hard finishing." This, he says, will lead to calls for even higher productivity and accuracy. ME
This article was first published in the August 2012 edition of Manufacturing Engineering magazine. Click here for PDF.