January/February 2019

Archive > 2019 > January/February 2019

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Feature Articles

2019 State of the Gear Industry
Overall, the gear industry enjoyed a very strong 2018, and the optimism expressed by survey respondents is the highest in recent years. When asked about their optimism regarding their companies’ ability to compete over the next five years, 85.8% of respondents indicated some level of optimism.

Manufacturing Strong
For this year’s exercise in large gears, we’re not going to dwell on size range or length, merely look at the fundamental challenges and latest technologies required to manufacture large parts in the gear industry. This could be a gearbox assembly for the construction, mining or oil and gas industries or simply a large standalone gear pinion set for a custom application. Whatever the industry or application, large gears require more preparation, planning and precision than other areas of gear manufacturing.

The Growth of Australian Regenerative Load Testing
Historically, gearbox original equipment manufacturers (OEMs) and repair organizations have tended to offer their customers no-load, full speed (spin) tests as a standard performance test. If a load test was specified, the supplier would probably offer a locked torque back-to-back simulated load test, which requires a large investment in tooling to connect shafts of the test and slave gearboxes.

Getting in Sync
Gear skiving is here to stay, and as a result of this industry shift, it’s become paramount to improve how well machining spindles synchronize with each other.

The Quest for the All-in-One Machine
Multitasking machines have a pretty clear sales pitch: They can do what you need them to and make a gear, but if you’re a job shop with fingers in a lot of pies, you can also use them for anything else you might need to make. Hobbing, cutting, milling, now even gear skiving; if it’s a cutting process, a multitasking machine can probably do it.

Beautiful on the Inside
Automotive gear manufacturers have implemented significant improvements in external planetary gear manufacturing yielding quieter gears. In addition, process stability has increased due to the post-heat treatment finishing processes employed. This article explains various complete solutions for cutting and finishing internal ring gears.

Technical Articles

CNC Milling of Straight and Spiral Bevel Gears
Contrary to what appears to be popular belief, 5-axis CNC gear manufacturing is not limited to milling with end mill, ball mill or CoSIMT (Conical Side Milling Tool — it is the generic form of the Sandvik InvoMill and Gleason UpGear tools.) tools, where throughput is too low to prevent production at any significant level. Straight and spiral bevel gear manufacturing on 5-axis CNC machines using face mill cutters provides essentially the same throughput as conventional gear cutting machines — with added benefits.

Flank Profile Modification Optimization for Spur Asymmetric Gears
In many gear transmissions, tooth load on one flank is significantly higher and is applied for longer periods of time than on the opposite one; an asymmetric tooth shape should reflect this functional difference. The advantages of these gears allow us to improve the performance of the primary drive tooth flanks at the expense of the opposite coast flanks, which are unloaded or lightly loaded during a relatively short work period by drive flank contact and bending stress reduction. This article is about the microgeometry optimization of the spur asymmetric gears’ tooth flank profile based on the tooth bending and contact deflections.

Simulation of Spiral Bevel Gear Tooth Manufacturing to Aid in One-Piece Gear Shaft Design
In helicopter applications, the two-piece gear is typically joined by welding, bolts, or splines. In the case of the U.S. Army CH-47D Chinook helicopter, a decision was made to eliminate these joints through the use of integral design. Integral shaft spiral bevel gears must be designed such that the shaft does not interfere with gear tooth cutting and grinding. This paper discusses techniques to iterate in the design stage before manufacturing begins.

Large Bevel Gears for Crushing Applications
Large bevel gears drive the crushing machines used to process ores and minerals in the hard-rock mining and aggregates industries. This paper is intended to help the reader understand the unique aspects of these machines, and why crushing applications fall outside the traditional automotive paradigm for bevel gears.

Departments

Gravy Training (Publishers Page)
We’ve just come off a very strong year for gear manufacturing, and most of you are looking forward to another good year in 2019. At least, that’s what the results of our annual State-of-the-Gear-Industry survey tell us.

Product News (Product News)
The complete Product News section from the January/February issue of Gear Technology.

State of the Gear Industry Special Edition (Ask the Expert)
Gear industry experts give their opinions about the most important trends facing gear manufacturers today.

Calendar (Events)
The complete Technical Calendar from the January/February 2019 issue of Gear Technology.

Industry News (Industry News)
The complete Industry News section from the January/February 2019 issue of Gear Technology.

Hyperloop is Coming (Addendum)
Before Dr. Who, there was Professor Quartermass (a 1950s BBC TV and film creation). And, in the-here-and-now, there is Elon Musk — a flesh-and-blood living legend in his own time — or mind: take your pick. But the point here is that he’s for real — not a fictional sci-fi icon.