As we ring in the New Year, it is commonplace for people to reflect on the prior twelve months and to make resolutions about their physical, mental, and financial health with emphasis on improvements in the coming year. These reflections help to shape ideas to improve mobility, agility, and longevity. Just as we review ourselves, the new year is an excellent time to review the performance of our gear systems.
One favorite resolution for the new year is to try to lose weight. In some gear systems, there is an opportunity to reduce the weight of certain gear components. The lower mass of the gearing will result in reduced inertia. The reduction in inertia will allow the motors to work less and for the system to be more efficient. Unfortunately, gears do not have the option of joining a gym or starting a walking regimen to lower their weight.
One method to reduce the weight of the gearing in any system is to evaluate the possibility of replacing a steel gear with a polymer gear. In some designs, a polymer gear is added to create a known point of failure. This sacrificial gear is introduced to the gear system to prevent other components from being damaged in the event of a failure within the system. In other cases, a polymer gear can be introduced to the system to reduce vibration or to reduce noise. As some polymers contain lubricating properties, gears made from these materials might be employed to add lubrication to the gear system.
Another method to reduce weight is to change the shape of the gear by machining unnecessary material. One method to reduce the weight is to add lightening holes through the side face of the gear (Figure 1).
These holes are designed to be significantly large enough to reduce the weight but small enough to maintain the structural integrity of the gear. Another method, similar to lightening holes, is to trepan the side faces (Figure 2). This machining technique removes material from the side face from the hub diameter out to near the root diameter. This technique will result in the gear having a webbed section. The recommendation for the thickness of the web is to be no less than forty percent of the width of the gear tooth. By removing only thirty percent of the side face material from each side of the gear, the weight is reduced but the strength of the gear will not be affected.
The performance of a gear system can be improved with the introduction of a gear lubrication system (Figure 3). These products consist of a pump assembly, tubing, and a lubricating pinion. These systems introduce lubrication into the gear system via the pinion. The user calibrates the pump to dispense gear oil or grease at a pre-set rate. The lubricant is then pumped through the tubing and into the pinion. The pinion is made from a porous polyurethane foam that deposits the lubricant onto the gear or rack with which it is mated. These types of lubricating systems are excellent choices for applications that are not enclosed and are not suitable for spray lubrication.
Another way to improve a gear system is to evaluate the mating components of the gears. The bearings for the shafts should be reviewed for wear and proper lubrication. If the bearings have lost their lubricant or are worn, this will greatly contribute to the premature failure of the gearing. It will also increase the noise and vibration of the mechanism. Additionally, the shafts should be inspected to ensure that they are still properly aligned. Misalignment of the shafts will result in gearing that does not operate at the proper mesh point.
A preventative maintenance plan is the best way to evaluate the condition of your gearing system. Checking the system for abnormal wear patterns, excessive vibration and increased noise are excellent tools to ensure that the gearing in your system is set for success in the coming year. Take the time to access yourself and your machinery and you will have a prosperous new year.
