Articles About Grease Seals
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The complete Industry News section from the December 2019 issue of Power Transmission Engineering.
Whether you design, build or maintain industrial equipment, it is likely you have encountered many types of bearing grease over the years. Lubrication plays a crucial role in virtually all operations, and certain key characteristics allow grease to perform its job better in demanding applications.
Custom PEEK Compounds have led to the development of transmission seals and thrust washers that offer lower wear, friction and temperature advantages.
For a maintenance crew, it is important to know which bearings need re-lubrication and make sure they are lubricating those bearings. The bearings can be lubricated manually or by automatic lubrication systems. This article will review each method and discover its pros and cons.
Latest Sealing Technologies Offer Optimum Wear and Frictional Characteristics.
Sustainability is becoming one of the most important aspects within the power transmission business. Users demand low-maintenance drive systems with as little disruption as possible, and expect lifetimes of more than 10,000 hours. Approximately 40 percent of long-term gearbox leakages can be traced back to poor interaction between the radial shaft seal (RSS) and the lubricant. Thus, it becomes essential to analyze the tribological system as a whole, which includes the gear oil, seal grease (if required), elastomer material and design, and the shaft.
In this study the mechanical shear degradation of lithium-thickened grease was evaluated using an in-house-developed aging rig and a commercial rheometer. It was found that this grease loses its original consistency during aging and shows a two-phase aging behavior. In the first phase, primarily reorientation and breakage of the thickener network take place, resulting in a progressive drop in the grease's rheological properties. After this, the aging is dominated by the breakage of smaller fiber fragments and the grease degrades at a much slower rate.
SKF Product Investigation Center Troubleshoots Critical Rotating Equipment Applications with Analysis, Research and Testing Procedures.
Equipment downtime and reduced component life are a few of the consequences â” and potential costs â” of using the wrong seals on many types of industrial equipment including pump bearing frames, electric motors, fans, pillow blocks, gearboxes and more. However, if correctly specified and installed, seals provide effective barriers that both retain lubricants as well as protect against water, corrosion, debris and other contaminants.
For the lubrication of open gear drives used in different industrial applications such as cement and coal mills, rotary furnaces, or where the sealing conditions are difficult, semi-fluid greases are often used in preference to fluid oils. For girth gear applications the greases are used with a splash or spray lubrication system. The selection of such greases influences pitting lifetime and the load-carrying capacity of the gears, as well as wear behavior
End users and OEMs frequently specify "lubed-for-life" mounted bearings, thinking the lubed-for-life bearings will deliver the same life â” without lubrication â” as bearings that currently require periodic lubrication. The truth is it depends on many factors, and only a detailed review of the application and testing will provide a more accurate answer.
conveying system on the varnishing line for a manufacturer of high-end kitchen cabinets were leaking. Oil was dripping on the cabinet parts â” ruining the finish. Why were half of the gearboxes leaking?
U.S. manufacturers, such as food processors, face an unprecedented competitive environment and must look for ways to be profitable without negatively affecting the quality of finished products.
Iâ™m building a custom gearbox with 7075 T-6 spur gears, and Iâ™m concerned that aluminum flakes will enter the races on the roller bearings (SKF 2307) and cause premature failure. So my question is â” should I place an oil seal on the shaft first to protect the bearing â” or is this an unfounded concern and I should mount the seal in the typical manner outside the bearing? Or both? Or go with a sealed bearing? Iâ™m confused and could use your expertise, please.
The improvement of the energy efficiency of industrial gear motors and gearboxes is a common problem for many gear unit manufacturers and end-users. As is typical of other mechanical components, the radial lip seals used in such units generate friction and heat, thus contributing to energy losses of mechanical systems. There exist today simulation tools that are already helping improve the efficiency of mechanical systems â” but accurate models for seal frictional losses need to be developed. In this paper SKF presents an engineering model for radial lip seal friction based on a physical approach.
Varying installation requirements for worm gears, as, for example, when used in modular gear systems, can necessitate grease lubrication - especially when adequate sealing for oil lubrication would be too complex. Such worm gears are being increasingly used in outside applications such as solar power plants and slew drives. While knowledge about the operating conditions is often appropriate, the basic understanding for load capacity and efficiency under grease lubrication is quite poor. Investigations done at FZG and sponsored by FVA/AiF are shown here to give an impression of the basic factors of load capacity and efficiency. The results of the investigation indicate a satisfying quality of calculations on heat, load capacity and efficiency based on characteristic parameters of the base oil with only slight modifications to the methodology known from DIN 3996 or ISO TR 14521.
The following news items offer the latest on lubrication and seal technology in the power transmission market. From bearing greases to high-performance seals, these products will help extend the service life and manufacturing capabilities for a wide range of industrial sectors.
For either brand-new motors or those already in service, "best practices" means that informed technicians can make use of the latest diagnostic techniques (vibration analysis, thermography, shaft-voltage testing, etc.) to prevent electrical bearing damage -- either at the very beginning or very quickly thereafter. If done correctly, the work need only be done once.
Grease lubrication has clear advantages over oil lubrication: Grease does not leak easily; it has sealing properties; and it protects bearing surfaces from corrosion. Its disadvantages are grease-life limitations and a limited cooling ability. Moreover, in some applications there is a risk of grease starvation, which leads to reduced lubricating films. However, if the right grease, sealing system and/or lubrication system are chosen, then grease lubrication offers clear benefits. This article summarizes aspects of grease lubrication mechanisms in rolling bearings.
Seal design engineers and end users are continually seeking improved sealing systems and materials. This paper describes the potential of a new thermoplastic polyurethane (TPU) material to deliver improvements in pressure, speed and temperature capability, which are presented as comparisons to proven industry standard materials. Performance is demonstrated by virtue of test bench results of seals made from MDI-, PPDI- and NDI-based materials.
In an industrial application, equipment uptime is vital for on-time performance and profitability. The rotating members of industrial machines are subject to the highest degree of wear and are more susceptible to failure than non-moving parts. Bearing surfaces are the most critical and often the most expensive portion of the rotary assembly; it is imperative to protect these components. The primary protector of these components is the industrial seal.
Th e primary sources of bearing failure are lack of lubrication and contaminant ingress. Industrial sealing devices are the primary protection against bearing failure. When the sealing device fails, bearing failure is imminent. Th erefore, extending the life of sealing devices extends bearing life and in turn improves equipment uptime.