Crossed Roller Bearing

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A thin bearing with rollers crossed at right angles, letting a single unit carry loads from every direction.

A crossed roller bearing places a single row of cylindrical rollers in a V-shaped raceway between its inner and outer rings, with neighboring rollers' axes alternating at right angles to each other; this lets one bearing simultaneously carry radial force, axial force in both directions, and tipping moments, where an ordinary bearing arrangement would typically need a matched pair to do the same job. It has a thin cross-section, high stiffness, and good rotational accuracy, and is commonly used at a robot joint's output and in turntables; many harmonic-drive units even include one as a built-in output bearing that carries external loads directly. The trade-off is that it demands high precision from the mounting surfaces, and it costs more.

ExampleIn a collaborative robot-arm joint module, a crossed roller bearing at the harmonic drive's output commonly supports the bending moment transmitted from the end of the arm.

Also called: Crossed Cylindrical Roller Bearing
Related: Strain Wave Gear (Harmonic Drive) · Thin-Section Bearing · Joint Actuator Module · Stiffness · Core Components · Payload
Sources: Rolling-element bearing - Wikipedia