1. Bearing axis
The theoretical axis of rotation for rolling bearings refers to the axis of the inner ring for radial bearings and the axis of the shaft ring for thrust bearings.
2. Inner ring (shaft washer) axis
The axis line of the basic cylindrical hole or conical hole of the inner ring (shaft ring) that is connected to the inner cylinder or cone.
3. Outer ring (housing washer) axis
If the outer surface of the outer ring is cylindrical, the axis line of the outer cylinder on the outer surface is the axis line of the outer ring. If the surface is basically spherical, the axis line of the outer ring is the line perpendicular to the reference end face of the outer ring through the center of the sphere on the outer surface of the ring.
4. Cone (cup) axis
The axis line of the inner (outer) ring of a tapered roller bearing.
5. Radial plane
The plane perpendicular to the axis and parallel to the reference end face of the ring or the back face of the gasket can be considered a radial plane.
6. Radial direction
The direction passing through the axis in the radial plane.
7. Axial plane
A plane that includes the axis line.
8. Axial direction
Parallel to the axis of the bearing. The direction perpendicular to the reference end face of the ring or the back face of the gasket can be considered as the axial direction.
9. Radial (axial) distance
Distance measured radially (axially).
10. Contact angle (nominal contact angle)
The angle between the plane perpendicular to the axis of the bearing (radial plane) and the line of action of the resultant force transmitted to the rolling elements through the bearing ring or washer (nominal line of action).
11. Nominal contact point
The point where the rolling element contacts the raceway surface when the bearing components are in normal relative position.
12. Reference face of a ring (a washer)
The end face of the ring (washer) designated by the bearing manufacturer as the reference surface can be used as the benchmark for measurement.
