Local coordinate system for all components

The position and orientation of the local coordinate system (if available) for each component type is defined in this section.

Terminology

Term	Definition
End point	Each component has two end points. These are the points with the maximum axial distance from one another when the component is projected onto the shaft axis. One of these end points will be defined as the left end point, the other as the right end point.
Total width	The axial distance between the two end points.
Midpoint	The point on the shaft axis halfway between the two end points.
Midpoint plane	The plane which includes the midpoint and is perpendicular to the shaft axis.

Figure 1. Definition of terms on an example shaft

A: End points, B: Midpoint, C: Total width

Definition of the u-axis

Component	Definition of the u-axis
All component types	The u-axis runs along the shaft axis from the left to the right side of a component. Notice Change from REXS version 1.4 Clarification: the viewing direction or "left" and "right" can be defined separately for each component which has a coordinate system. In particular, the u-axis of a component on a shaft does not necessarily need to point in the same direction as the u-axis of the shaft itself.

Definition of the v- and w-axes

Component

Definition of the v and w-axes

shaft

Not specified, as a shaft is generally rotationally symmetrical. The sections that make up a shaft are lined up in order along the u-axis.

cylindrical_gear

ring_gear

The w-axis points to the midpoint of the first tooth in the midpoint plane. The datum_face_orientation attribute indicates whether the datum face is in the positive or negative direction with respect to the local coordinate system of the gear.

Rightward leaning (b > 0)

Leftward leaning (b < 0)

bevel_gear

The w-axis points toward the center point of the first tooth in the plane perpendicular to the shaft axis. The bevel_cone_orientation attribute specifies whether the bevel tip lies in a positive or negative direction relative to the local coordinate system of the bevel gear.

worm_gear

worm_wheel

The w-axis points toward the center point of the first tooth in the plane perpendicular to the shaft axis.

rolling_bearing_with_catalog_data

rolling_bearing_with_detailed_data

The angular_position_around_u attribute is used to specify the angular position of the rolling elements. The angle is counted from the v-axis. See position_of_rolling_elements.

Position of the coordinate origin

Component	Position of the coordinate origin
shaft side_plate	The origin of the local coordinate system is the left end point.
bevel_gear	The origin of the local coordinate system corresponds to the projection of the design point P on the gear axis. For bevel gear stages without axial offset, the design point is located at a height equal to half of the width of the gear (ISO 23509 2006 A.3). For hypoids, there are multiple methods for selecting the design point; therefore, the position of the design point may differ from the center of the tooth width; see ISO 23509 2006 A.3 for details. Deviations from the tooth center arise for both gears when using method 1 (Gleason) as well as for the pinion when using method 3 (Klingelnberg).
All other component types	The origin of a component is its midpoint.

Component

Position of the coordinate origin

shaft

side_plate

The origin of the local coordinate system is the left end point.

bevel_gear

The origin of the local coordinate system corresponds to the projection of the design point P on the gear axis. For bevel gear stages without axial offset, the design point is located at a height equal to half of the width of the gear (ISO 23509 2006 A.3). For hypoids, there are multiple methods for selecting the design point; therefore, the position of the design point may differ from the center of the tooth width; see ISO 23509 2006 A.3 for details. Deviations from the tooth center arise for both gears when using method 1 (Gleason) as well as for the pinion when using method 3 (Klingelnberg).

All other component types

The origin of a component is its midpoint.

In this section:

REXS Specification