Over the past few months we've talked with a lot of gear manufacturers. Many of them tell us business is strong, while others are struggling with reduced demand. The difference between them isn't so much in the quality of their manufacturing operations, but rather trends in the end markets they serve.
By increasing the number of gears and the transmission-ratio spread, the engine will run with better fuel
efficiency and without loss of driving
dynamics. Transmission efficiency
itself can be improved by: using fuelefficient transmission oil; optimizing the lubrication systems and pumps; improving shifting strategies and optimizing gearings; and optimizing bearings and seals/gaskets.
This paper presents how low pressure carburizing and high pressure gas quenching processes are successfully applied on internal ring gears for a six-speed automatic transmission. The specific challenge in the heat treat process was to reduce distortion in such a way that subsequent machining operations are entirely eliminated.
Beveloid gears are used to accommodate a small shaft angle. The manufacturing technology used for beveloid gearing
is a special setup of cylindrical gear cutting and grinding machines. A new development, the so-called Hypoloid
gearing, addresses the desire of gear manufacturers for more freedoms. Hypoloid gear sets can realize shaft angles between zero and 20° and at the same time, allow a second shaft angle (or an offset) in space that provides the freedom to connect two points in space.
This paper will present data from both laboratory and field testing demonstrating that superfinished components exhibit lower friction, operating temperature, wear and/
or higher horsepower, all of which translate directly into increased fuel economy.