There is an old saying that “the fools always win in the end because stupidity has no limits, while genius does.” Occasionally we see this acted ou...

Delta’s Investment in New Mitsubishi Equipment Adds Capacity, Reduces Cycle Time Dwight Smith, Vice President, Mitsubishi Hea...

News on the latest products in the industry.

  As one of our trade’s more accessible “experts,” I am happy to field questions from the general public, too. This week one of the more un...

Comprehensive descriptions of what you will find in the booths of many leading gear industry suppliers at IMTS 2016.

Gear Technology interviews Scott Yoders of Liebherr about the latest gear machining technologies of relevance to automotive manufacturers.

A best practice in gear design is to limit the amount of backlash to a minimum value needed to accommodate manufacturing tolerances, misalignments, and deflections, in order to prevent the non-driving side of the teeth to make contact and rattle. Industry standards, such as ANSI/AGMA 2002 and DIN3967, provide reference values of minimum backlash to be used in the gear design. However, increased customers' expectations in vehicle noise eduction have pushed backlash and allowable manufacturing tolerances to even lower limits. This is especially true in the truck market, where engines are quieter because they run at lower speeds to improve fuel economy, but they quite often run at high torsional vibration levels. Furthermore, gear and shaft arrangements in truck transmissions have become more complex due to increased number of speeds and to improve efficiency. Determining the minimum amount of backlash is quite a challenge. This paper presents an investigation of minimum backlash values of helical gear teeth applied to a light-duty pickup truck transmission. An analytical model was developed to calculate backlash limits of each gear pair when not transmitting load, and thus susceptible to generate rattle noise, through different transmission power paths. A statistical approach (Monte Carlo) was used since a significant number of factors affect backlash, such as tooth thickness variation; center distance variation; lead; runout and pitch variations; bearing clearances; spline clearances; and shaft deflections and misalignments. Analytical results identified the critical gear pair, and power path, which was confirmed experimentally on a transmission. The approach presented in this paper can be useful to design gear pairs with a minimum amount of backlash, to prevent double flank contact and to help reduce rattle noise to lowest levels.

Although the official astrological start to summer in the northern hemisphere is still three weeks away, the Memorial Day weekend just concluded ma...

According to the U.K.-based WITT Energy website (witt-energy.com), "The WITT is the only device in the world that can capture energy from all movement and turn it into electricity. No other energy system can exploit the full spectrum of movement, enabling it to harvest power from water (sea, river or tidal), wind and human or animal motion."