Wheel Hub Cracks of Heavy-Duty Vehicles due to Drum Brake Shoe-Lining
Wear, Friction, and Self-Lock 2024-01-5037
Wheel hubs with drum brakes of heavy-duty vehicles rarely broke, but some
suddenly cracked in the 2000s. The cause of damage was said to be a lack of hub
strength. However, the case was suspicious because the hubs were produced
according to the design guidelines by the JSAE.
In the 1990s, brake shoe-lining materials were changed from asbestos to
non-asbestos for people’s health. The brake squeal and abnormal self-lock
frequently occurred because of the increased friction coefficient between drum
and shoe lining in the case of the leading–trailing type. The mechanical
friction coefficient changes with the material and the contact angle, which
varies with the wear of shoe lining and the drum temperature.
In the previous report, the deformation of the wheel hub under the abnormal
self-lock was verified by observing the change of hub attitude in model test
equipment. In this paper, a causality between the hub crack damage and the
abnormal friction increase is clarified by predicting the bending moment and
fatigue life of the wheel hub, which changes with friction forces and tire load
levels. It has been concluded that the abnormal increase in bending moments from
brakes and tires considerably shortens the durable life of wheel hubs.
