Gantry robots – The defining feature of a gantry is that it has two X (and sometimes two Y and two Z) axes. Their high load capacity allows heavy loads to be transported, and the rigidity of the linear rail helps to stiffen the entire system. Overhead transport systems – When loads are centered below the rail and bearing block, as is often the case with overhead transport systems, linear rails are a good choice for guidance. Linear actuators often incorporate a single linear rail with one or two bearing blocks. They can also accommodate travel speeds up to 5 m/sec, which is important in belt or pneumatic driven systems. Linear actuators – Linear rails are often the guide mechanism of choice for actuators that are driven with belts, screws, or pneumatic cylinders, because of their ability to withstand moment loads. Here are a few examples of applications that use a single linear rail. (In contrast, round shaft linear guides must be used in pairs when overhung loads are present.) Because of this feature, numerous applications use a single linear rail, to save space or to prevent issues with misalignment among other components in the system. All of these attributes combine to provide a linear guide system that is perfectly suited for applications that require high precision, high rigidity, and long life.īecause linear rails have load-supporting balls (or rollers) on each side of the rail, they can withstand overhung loads, even when just a single rail is used. And with two, four, or six rows of rolling elements – either spherical balls or cylindrical rollers – stiffness is high and deflection of the bearing block is minimal. Linear guides also provide a high level of travel accuracy, thanks to precise machining of one or both edges of the rail, which act as reference surfaces. When compared to plain bearing guides, linear rails have higher stiffness and rigidity, and often have better load/life characteristics. And unlike crossed roller guides, for which travel is often limited to 1 meter or less, linear rails can provide very long travel lengths. For example, round shaft guides can withstand only downward or liftoff loads, whereas linear rail guides can withstand both downward/liftoff loads and moment loads. The reasons for using linear rails are numerous, but their most obvious benefits over other types of guides are load capacity, travel accuracy, and rigidity. Their variety of sizes, accuracy classes, and preloads make linear rails suitable for virtually any performance requirement. The backbone of many industrial applications, they provide low-friction guidance and high stiffness for loads that can range from just a few grams to thousands of kilograms. Linear rails are linear assemblies that have twin parallel tracks containing load-supporting balls or rollers.
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