Choosing the Right Bearing for Your Robot

As robotics continue to advance, the significance of high precision components is higher than ever for accuracy and overall performance. Bearings play a vital role in enabling the smooth and precise movement of robotic joints, as robots cannot do any of the picking or lateral movements without bearings.

The choice of bearings significantly influences the efficiency, reliability, and longevity of robotic systems. There is now a fundamental distinction when identifying classical industrial robots typically used for welding, painting, and handling heavy components and lightweight robots used in assembly with lighter loads up to 50 lbs. Lighter-weight robots maximize payload and reduce inertia, which improves response. This is only possible with the use of thin section bearings.

Thin Section Bearings for Industrial Robots

Kaydon Reali-Slim® bearings is a good starting point to begin your search for robotic application bearings. As robotic designs continue to grow, many design engineers are specifying Kaydon. Kaydon robotic bearings offer compact and lightweight bearings to increase payloads and minimize power requirements.

RBC Bearings is another world class bearing manufacturer who offers a full line of thin section bearing types for demanding robotics applications. Today’s improved robotic designs rely on compact designs, light weights, and small cross section bearings. Thin section bearings are the best solution for robotic designs.

The various series of thin section bearings keep the same cross section dimension even though the bore increases. This type of design allows for hollow shaft designs where other components like air, electric, or hydraulic lines can be used for passage. Other designs like the four-point contact thin section RBC bearing can replace a pair of bearings for a more compact design and steady performance.

Bearings and Components for Robotics

Schaeffler Corporation is the best in the industry, offering many components and bearings for robotics.

Schaeffler Bearing Company has the most extensive portfolio of bearings and components for robotics. Schaeffler offers a precision strain wave gear series for classical and lightweight robots, with a torque sensor integrated into the strain wave gearing. Schaeffler also offers the PSC series (the “P” stands for “precise,” the “S” for “silent,” and the “C” for “constant,” marking a constant level of precision) of precision planetary gear units for industrial robotics.

Schaeffler offers two precision strain wave gears series for classical and industrial lightweight robots. In addition, Schaeffler offers the PSC series of precision planetary gear units for industrial robots. The Schaeffler offering includes a wide range of robotic linear solutions including applications in reach extension or in gripping systems.

INA standard and high-torque series components are available as pre-assembled and articulated arm units.

The motor, strain wave gear, output bearing support, and an optional integral torque sensor create a perfectly tuned mechatronic unit. You can expect extremely high torque density, accuracy, and long service life when specifying this unit.

Crossed roller bearings are ideal for high-rigidity joint bearings. Short spacers are used in the INA XSU series to separate the cylindrical rollers, reducing friction and running noise.

INA SGL angular contact roller bearings are widely accepted by precision gearbox manufacturers as INA angular contact roller bearings are extremely rigid. With their compact cross section, the angular contact roller bearing is exceptionally accurate for use in robotic joints. For robotic applications they are mainly used in servo drives, robotic joints, and as output bearings in planetary gearboxes.

INA offers an alternative to the crossed roller bearing when the robotics application requires more tilting rigidity. INA XZU series angular contact needle roller bearings have identical external dimensions to crossed roller bearings.

They are also conveniently interchangeable with each other. Two separate raceways provide a support distance which increases rigidity while the cages precisely guide the rollers, reducing friction and allowing room for more lubrication, as necessary.

INA’s state-of-the-art monorail guidance systems are ideally suited for many industrial robotic applications. The raceways are manufactured in an “X” arrangement, offering high-speed variants up to 10 m/s without use of expensive special materials, and have six-row recirculating ball bearing and guideway assemblies.

Through Schaeffler Bearing and other manufacturers like Kaydon, RBC, SKF, and INA, Pacific International Bearing offers much more than just rolling bearings. PIB is your strategic partner for robotic system components, precision gearboxes, pivot bearing supports, drive motors, and sensors.

Other types and designs are available in robotics

Plain bearings, also known as sleeve bearings or bushings, offer simplicity and cost-effectiveness for certain robotic applications. They consist of a shaft and a bearing surface, which could be made of various materials such as metal, plastic, or composite.

Key types of plain bearings used in robotics include:

•  Journal Bearings

Journal bearings support shafts by providing a low-friction surface between the rotating shaft and the bearing housing. They excel in applications requiring smooth rotation and low-noise levels such as robotic joints, articulated arms, and rotary tables.

• Thrust Bearings

Thrust bearings are designed to withstand axial loads, ensuring the efficient transmission of axial forces within robotic systems. They are commonly used in robotic actuators, gearboxes, and applications where axial forces are prevalent.

• Magnetic Bearings

Magnetic bearings employ electromagnetic forces to levitate and control the position of a rotating shaft without any physical contact. They offer several advantages, including high-precision, maintenance-free operation, and reduced friction and wear. Magnetic bearings find applications in precision robotic systems, such as robotic surgery, semiconductor manufacturing, and high-speed robotics.

• Hybrid Bearings

Hybrid bearings combine the benefits of different bearing types, offering improved performance and versatility. They often integrate ceramic rolling elements with steel races, enhancing stiffness, durability, and corrosion resistance. Hybrid bearings are suitable for various robotic applications that require a balance between high-speeds, heavy loads, and long service life.

Conclusion

Selecting the right bearing for a robot is a critical step in ensuring optimal performance, reliability, and longevity. By considering load capacity, speed, precision requirements, environmental factors, maintenance requirements, and various bearing types, engineers can make informed decisions.

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