자동차 유압브레이크용 고무호스의 내구성 시험 및 미세손상에 관한 연구

Abstract

Rubber hose assembly for automotive hydraulic brake during operation is subject to combined stresses of

cyclic pressure, cyclic bending and torsion as well as thermal load. The rubber hose is composed of

ethylene-propylene diene monomer(EPDM) rubber layers reinforced by polyvinyl acetate(PVA) braided fabrics. A

durability tester with loading rigs for inducing the above cyclic stresses was used to investigate failure

mechanisms in the rubber hose assembly. Failure examination was performed at every 100 thousands cycles of

bending and torsion. Hose samples were sectioned with a diamond-wheel cutter and then polished. The polished

surface was observed by optical microscope and scanning electron microscope (SEM). Some interfacial

delamination with a length of about 1mm along the interface between EPDM rubber and PVA fabrics was

shown at the test cycles of 400,000. The delamination induced some cracking into the outer rubber skin layer

to leading the final rupture of the hose.