在2017年一月刊的美国《Gear Solutions》杂志中， 来自康明斯（Cummins）的资深的工程师发表了一篇名为“Optimizing Gear Macro and Microgeometry To Minimize Whine and Maximize Robustness for a Diesel Engine Application”的文章。文章详细介绍了如何使用MASTA  优化齿轮的宏观和微观参数，在不牺牲安全系数的情况下降低传递误差（TE），最大化地降低了齿轮啸叫，最小化地改变了传动系统的稳健性（齿轮的弯曲、接触、胶合及微点蚀），为读者提供了非常好的齿轮设计分析经验和齿轮降噪方案。

Optimizing Gear Macro and Microgeometry To Minimize Whine and Maximize Robustness for a Diesel Engine Application

BY
Neil McNab, Greg Mitchum & Erik Ostergaard


A system approach is used to optimize the macro and micro design to minimize the transmission error while ensuring that robustness (bending, contact, scuffing, and micropitting) safety factors are not compromised.

The desire for engines that provide more torque and power is driving higher loads into the gear train. At the same time, expectations for noise, vibration, and harshness (NVH) require systems that are even more refined. The gear train design engineer has several factors available to consider; some are controllable, and others are not.
Given:
Accessory speed ratios
Engine speed range
Architecture-specific shaft positions (camshaft, crankshaft, etc.)
Available packaging space
Free variables:
Module
Tooth counts
Helix angle
Pressure angle
Idler shaft positions
Lead and profile crowning
Tooth width (within space constraints)
Gear manufacturing techniques
Gear material
All of these variables must come together in a design that meets both durability and NVH targets, while produced economically. Because few of the variables are truly independent, a system approach was used to find the solution.
Background
The current gear train design (baseline) has a 45 toothed crank gear. This suffered audible gear whine most noticeably at low idle; 700-1,000 rpm while under low load. In the vehicle, it was audible around 1,200-1,400 rpm under light loads. Even though gear whine is significant at higher rpm, engine noise effectively masks it at this speed.  


#MASTA #NVH

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