When a linear motion solution is in place & running, it’s easy for the casual observer to think it looks easy. That’s what our industry is all about; making the difficult or even impossible look easy.
But what few people outside the industry realize is just how much work needs to go into the design of a successful linear motion system. The old adage “Measure twice, cut once” doesn’t even begin to cover all the variables, that have to be dealt with.
Now, a new app looks to make that successful design at least a little easier. The Design Guide Pro not only offers selectors for Bevel Gears, Worm Gear Jacks, Bearings and Electric Cylinders, but it also has a calculator section. Here, you’ll find tools to help you establish Energy, Critical Speed, Column Load, Torque and Nut Life as well as helping with Unit Conversions.
All in the palm of your hand. Check it out today by clicking here.
In the linear motion industry, bearings are crucial to an endless number of applications. That being said, there are numerous factors to be considered when trying to find the best bearing for your application. And that can be a time-consuming process. Until now…
Introducing the DesignGuidePro application from Nook Industries. The application makes for easy navigation when searching for design considerations for bearings. Simply plug in the desired specifications, and the app will provide a list of products best-suited for the application. Specifications include; load position, mounting and acceleration forces
DesignGuidePro puts the formulas right in the palm of your hand, and it’s free and easy-to-use. The application is compatible with both iOS and Android devices.
To try the app and make your worm jack selections easier, click here.
In order to get the best performance and life out of your linear bearings, proper lubrication is key.
A lubricant formulated for rolling friction should be used with linear bearings. In applications where operating speeds are low and loads are light, linear bearings can be used without lubrication at a greatly reduced life. However, it is never recommended to operate linear bearings without lubrication. To protect the highly polished bearing surfaces from corrosion and wear, a lubricant is required.
Where linear speeds are high, a light oil should be used and provision for re-lubrication should be made to avoid operating the bearings dry. For typical applications, a medium-to- heavy oil has good surface adhesion and affords greater bearing protection. Linear bearings 2 inches in diameter and above may use high pressure lithium grease such as Shell Alvania #2 for moderate speed applications. Lubricants containing additives such as molydisulfide or graphite should not be used.
In order to get the most life and best applications out of your bearings, it’s important to understand the size of the load, how the load will be applied and the length of the stroke. Applying too much weight to a load can significantly reduce the life and efficiency of your bearings. Also, incorrectly distributing the weight on the load can be harmful. In addition to some helpful design considerations, let’s take a look at the load considerations below.
Load ratings are the required design life, shaft hardness and bearing dynamic that affect the load and can be applied to a linear bearing. Two dynamic load ratings are given for each bearing size based on the rotational orientation of the bearing.
The normal load rating is used in applications where the orientation of the ball tracks relative to the load cannot be controlled. The normal load rating is based on a load imposed directly over a single ball track. The normal load rating shown in the specification tables is slightly greater than would be mathematically calculated based on one track loading, because it assumes that the load is shared to some degree by one or more of the adjacent ball tracks.
The maximum load rating assumes that the load is applied midway between two ball tracks as illustrated below. In this orientation the load is distributed over the maximum number of bearing balls.
The normal and maximum load ratings are based on a Rc 60 shaft hardness and a travel life of two million inches. For linear bearing system operating at less than full rated load, the Load-Life Curve may be used to determine the travel life expectancy.
An equivalent load value can be calculated when sizing linear bearings for applications at conditions other than maximum rating.