Proposal of high frictional and low aggressive abrasive shape (The effect of open angle for friction coefficient on degree of wear in abrasion)

Abstract

Disc brake is one of the most important auto mobile components and the toughest frictional components. Nowadays, the lightweight disc brake is needed for better fuel-efficient. To reduce the weight, high frictional and low aggressive brake pad is required. However, generally high friction cannot provide low wear of counter-part, therefore to make such brake pad is difficult. In addition, including many kinds of materials such as abrasive, binder, filler and so on, we cannot design it theoretically. In order to overcome these issues we focused on abrasive shape in brake pad, especially focused on open angle of abrasive φ and the important index “degree of wear f_ab”. If degree of wear f_ab decreases with open angle φ of abrasive and reduction of wear is more than reduction of friction, we can propose the high frictional and low aggressive brake pad which includes small open angle abrasive. In order to validate our proposals, we conducted the scratch test using Vickers indenter and Knoop indenter. As a result of the scratch test, we clarified that the ratio of wear coefficient to friction coefficient K / μ is correlated with degree of wear f_ab, and in the region of ploughing and wedge, degree of wear f_ab decreased with decreasing open angle φ. Due to these phenomena, the ratio of wear coefficient to friction coefficient K / μ decreased with decreasing open angle φ in the region of ploughing and wedge. Thus it was valid that small open angle abrasive provides high friction and low aggressiveness.