Bearing Rollers Information
Bearings with a rolling element (balls or rollers) minimize friction between rotating surfaces. Rolling elements are the load-carrying components of a bearing. The shape and finish of ball or rollers determine the nature of bearing operation by controlling the forces acting on moving parts. They enable rotational movement around a fixed axis.
Roller bearings rely on cylinders (instead of spheres) to separate the counter-rotating inner and outer rings. Such bearings decrease the friction caused by rotation and run at moderate-to-high speeds but are typically slower than ball bearings. The larger surface area of roller allows the device to support greater radial loads and limited thrust loads.
These units are manufactured from materials such as carbon steel, brass, chrome steel, stainless steel, aluminum, and plastic. Other specialized types consist of ceramics, titanium, gold, and silver.
Cylindrical bearing rollers: These devices are comprised of true cylinders that supply a large contact area with bearing rings to achieve an even load distribution over a wide surface area. Cylindrical roller bearings with two rows exhibit improved radial rigidity, making them suitable for high precision machine tools. Some cylindrical bearing rollers are designed without ribs on the inner or outer rings. This permits free axial displacement of the machine's encasement in relation to the shaft.
Tapered bearing rollers: These rotary bearings include four key components including a cone or inner ring, tapered rollers, a cup or outer ring, and an enclosure or cage to orient the rollers. Standard tapered rollers are made of chrome steel to achieve superior performance characteristics. These elements offer benefits such as dimensional stability, extended life, and enclosure durability.
Tapered rollers undergo a heat-treating process, known as thought-hardening, to yield uniform hardness and a smooth surface. Case-hardening offers a combination of a hardened surface with a robust and flexible core. These bearings serve heavy-duty tasks requiring moderate speed. Applications include:
- Axle systems
- Equipment designed for agricultural, construction, and mining
- Gearboxes and engine motors
Spherical bearing rollers: Devices featuring two rows of spherical (barrel-shaped) units between rings are suitable in heavy-load applications that experience substantial misalignment due to mounting or shaft deflection, as well as alternating directions of axial loads. The ability to self-align and withstand increased shock loads enables full-capacity loading even if shaft deflection occurs. Spherical roller bearings serve similar purposes as self-aligning ball bearings and convey heavy loads at low speeds. They are used in a vast array of applications:
- Combined harvesting machines
- Textile machines
- Woodworking machinery
- Overhead crane moving wheel and driving shaft
Cam (or track) follower bearings rollers: Bearings employing this roller type follow tracks or cams and are designed for linear motion systems. These consist of a full complement of rollers that balance the distribution of static loads. These bearing rollers feature a selection of configurations depending on the intended use. They are found on conveyors or product transfer lines across many industries, as well as in aerospace and defense applications.
Needle bearing rollers: Thin cylindrical rollers (needle rollers) with lengths of 3 to 10 times their diameter that function well in conditions with a minimal radial space. The small ratio of the ring diameter to the roller diameter allows for increased radial load capacity despite a low cross-section.Most needle roller bearings come without an inner ring. Drawn-cup models have pressed steel outer rings and are featured in such applications as:
- Valve trains
- Axle supports
- Power tools
Thrust bearing rollers: These are specialty bearings holding tapered or cylindrical rolling elements. Thrust bearings are engineered to sustain substantial axial loads in parallel to the shaft and also require lubrication in high-speed systems. They are assembled with two washers, or raceways, along with caged cylindrical rolling parts. Standard uses include automotive transmissions, where they stabilize the thrust load caused by angled teeth present in such systems.