Analysis of Bevel Gear Mounting Error Effects on Contact Patterns

Differences in bevel gear mounting errors affect the position and shape of contact patterns. Only when mounting positions are correct will gears run smoothly with reliable service life and noise performance.

Before formal use of bevel gears, we generally need to measure contact patterns to ensure correct gear manufacturing and installation. During the production stage, manufacturers need to check contact patterns on a test stand to ensure the gears mesh correctly. During final assembly commissioning, gears must be installed in the housing for contact pattern analysis to verify correct housing positioning.

When mounting positions are incorrect, we can often judge the error direction from the position and shape of the contact pattern, helping us adjust the gear to the correct position. After recording this position, the housing can be adjusted accordingly, ensuring mass-produced housings provide reliable noise and service life when bevel gears are installed.

The following describes how different positional errors affect contact pattern position:

We define positional mounting errors as shaft angle error, eccentricity E error, pinion axial P error, and wheel axial G error.

Contact pattern with correct mounting: The contact pattern is located near the midpoint.

Shaft angle error: If the mounting shaft angle does not match the design shaft angle, contact patterns on both left and right flanks simultaneously move toward the toe or heel.

Contact pattern with eccentricity E error: The contact pattern on one flank moves toward the heel while the other flank moves toward the toe.

Contact pattern with pinion axial P error: The contact pattern remains approximately near the midpoint in the face width direction, but on one gear both left and right flanks move toward the tip, while on the other gear both flanks move toward the root.

Contact pattern with wheel axial G error: The contact pattern remains approximately near the midpoint in the face width direction, but the contact pattern on one gear moves toward the tip while the other moves toward the root.

Both pinion axial error P and wheel axial error G cause the contact pattern to move toward the tip or root. Pinion axial error P is more sensitive to contact pattern movement than wheel axial error G. Moreover, both pinion and wheel axial positions are relatively easy to measure on a test stand.

Note: The above contact pattern position changes are based on the premise that the gears have been correctly designed. If the design itself is improper and contact pattern simulation has not been performed to confirm the correct contact pattern shape after proper mounting, the above methods cannot guarantee ideal contact patterns.

Note: The mounting position of bevel gears is extremely important. During machine design, we must repeatedly verify that after installing the housing, bearings, gears, and all other components, the pitch cone apexes of the two bevel gears coincide. Failure to check this during the design stage will lead to significant rework, wasting manpower and resources.

Note: Contact pattern test method: Install on a test stand or in a housing without applying grease or oil. Brush the tooth surface with pigment-mixed grease, then install on the test stand or in the housing, run unloaded for 30–60 seconds, and inspect the area where the pigment has been displaced.

Presented by ETAGEAR

11/20/2021 2:30:00 PM