To keep up with demand, higher precision is required for microprocessor manufacturing, diagnostic equipment, and automation. Linear crossed bearings can provide more precise motion control in tough applications than spherical bearings. Roller bearings and bushings are becoming increasingly popular in the manufacture of wafers, robotics, vision inspection, and high-tech microscopes. The cylinder-shaped bearings crisscross each other at a 90° angle and slide between the two parallel guides in these crossed roller bearings.
This type of linear motion bearing is precision-machined so that the rolling elements and inner and outer rings are perfectly aligned. This results in smoother motion, less vibration, and quieter operation.
Here are some benefits you can enjoy from using crossed roller bearings.
More Metal, Greater Loads
The load capacity of a roller door is defined by the amount of contact it has with the rail. Roller bearings are superior in load capacity and stiffness but have a lower maximum RPM than ball bearings. The small gap between the rollers, which may make a 250% load difference, can also affect load capacity. The rollers are enclosed in cages with a notch cut into both the top and bottom of the rollers. A retainer is a collar that fits over the roller, increasing the contact surface area by 30% to 58%.
Stainless steel cages are the most popular, costing a fraction of the price of aluminum cages and may be made entirely of stainless or steel. They can also endure high temperatures, medical uses, and water and rust resistance. However, outgassing can affect the resin, causing difficulties in high-vacuum systems.
The distance between the rails must be two times greater than the stroke because they move in opposite directions when using crossed roller bearings. A few re-circulating crossed rollers that aren't crisscrossed are found on a couple of crossed roller linear guide solutions. The resin cage allows a longer stroke length on the same length rail since the cage may be shorter for a given load. The difference between static and dynamic frictional resistances is minimal. Bearing manufacturers focus more on the static load because that's what machines must overcome when they're first turned on.
Linear crossed bearings can survive 150 million cycles for motion control applications with ultra-fast acceleration and deceleration. In addition, crossed roller bearing designs' anti-cage creep mechanisms can extend guide life and eliminate readjustments caused by uneven preloading on the inner and outer rings.
The wider contact surface of crossed rollers ensures constant, precise movement, and non-recirculation has less friction variation, making them extremely quiet and smooth. Also, linear bearing rigidity means less vibration, and the tracker uses crossed roller bearings to achieve an industry-leading positional accuracy of 2 microns.
Read here to know the difference between plain bearing and roller bearing.
In Conclusion
Bearing and bushes suppliers offer various crossed roller bearings for different applications. The main types are full complement, double row angular contact ball bearings, and cylindrical roller bearings. You can also find crossed roller slewing rings with internal or external gear teeth on the inner or outer ring.
When choosing crossed roller bearings, it's essential to consider the type of load, rigidity, required speed and acceleration, operating temperature, precision, and life expectancy. The size and shape of the bearing also need to be considered. If you're unsure what kind of linear motion bearing is best for your application, contact an expert who can help you select the right product.
