by Paul Dufresne, CLS, CMRP, CPMM, Trico
In tough working environments, machine reliability can be difficult to maintain - especially when contaminants threaten bearings and components. One such application is the universal driveshaft - a component that faces neglect due the extreme conditions and locations where they are used.
Contamination and corrosion due to chemicals and the operating conditions along with the lack of correct preventive maintenance not to mention improper storage and handling procedures may lead to premature failure. By following the preventive maintenance instructions and storage and handling procedures discussed in this article you may achieve extended life with your universal driveshafts.
In the fast paced production world today many assets are neglected due to the lack of correct preventive maintenance procedures. All too often these assets are neglected and are in a run-to-failure mode because companies have not taken the time to address the criticality of their assets. In the case of universal jackshafts, these are usually neglected due to the location and accessibility. Extreme guarding, lack of appropriate man power and shortage of PM time are the primary reasons for premature failure. Lack of adequate PM’s jackshaft will have a short life. The next few paragraphs will discuss in depth the re-lubrication frequency and process for maintaining the proper lubrication regimen for universal jackshafts. We will also discuss the dos and don’ts for proper relubrication and then finally proper storage and handling procedures.
Before you begin to re-lubricate your universal jackshaft you must ensure you have the correct grease needed for the jackshaft. There are many suitable grease on the market for by ensuring you have identified and are using the correct lubricant for this application you can begin the re-lubrication process.
Prior to starting the re-lubrication sequence ensure you follow the correct lock-out/tag-out safety procedures prior to removing any guarding and performing any work. Once the lock-out/tag-out procedures have been conducted remove the guarding. Be careful as the guarding may be heavy and may require additional help. Also, inspect the guarding to ensure the safety of it has not been compromised in any way. If the guarding has any issues please note on the work order so that it may be repaired as soon as possible.
U-joint and slip spline lubrication can have a significant impact on the operation and life of universal jackshafts especially in contaminated environments. For universal jackshafts, a highly quality lithium based EP NLGI 2 grease with good water tolerance and rust and corrosion protection is required. Prior to re-greasing the u-joints thoroughly clean the grease fitting and surrounding area to ensure all contaminants have been removed. Depending on the style of universal joint cross section used in your application you may have from one to four zerk fittings (See Item 1). When you start the re-greasing sequence ensure you purged all four seals of the universal joint. During this process it may be necessary to tap lightly on the end cap with a ball peen hammer to ensure the new grease can pass through all four internal grease channels and properly purged all four cap seals. If during this process and of the four caps do not purge with new grease make note and either replace bearing or shaft on the next available outage. At this point you now know you have a bearing(s) that are not getting lubricated and failure is imminent.
Item 1. Cross sectional diagram of the internal grease channels within a universal joint.
Courtesy of Dana Spicer
Storage & Handling
Improper storage and handling procedures also contribute heavily to premature jackshaft failure. All jackshafts should be stored in the horizontal position (See Item 2). Low cost wooden cradles can be built to house shafts in the store room or they can be stored on pallets. All shafts in storage should be re-lubricated every six months as part of an in storage maintenance program. Any shaft being pulled from storage and put into operation should be re-lubricated prior to being placed into operation. Care should be exercised when delivering shafts to the job site.
All shafts should be stored in dry and weather protected areas. If the Driveshaft is to be stored for a long period, the Flange connecting faces should be treated with an anti-corrosion agent.
Item 2. Picture showing proper storage and handling of jackshafts.
The recommended lubrication interval for Driveshaft’s used in Industrial plants in normal operating conditions is approximately every 500 hours. Unfavorable effects like temperature, dirt and water may necessitate shorter lubricating intervals. By following proper re-lubrication and storage & handling practices you can easily pro-long driveshaft life and mitigate early failures due to improper and infrequent lubrication. Neglecting the warning signs of a bad universal joint could cause the drive shaft to fail, damaging equipment making repairs more costly.
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