Friction material and manufacturing method thereof

Abstract

A friction material is provided with a matrix fiber, a binder, and a filler. The friction material contains a stabilized zirconia having a lattice constant in a range from 99.93 to 99.95% as compared with a lattice constant of a single crystal of stabilized zirconia. The lattice constant scarcely changes, since the stabilized zirconia contained in the friction material undergoes less introduction of distortions when used under severe conditions. Accordingly, the stable friction characteristic with less change of the friction coefficient in the initial stage of using the brake can be obtained.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing a relation between an annealing time and a lattice constant;

FIG. 2 is a graph showing the result of X-ray diffraction of calcia-stabilized zirconia;

FIG. 3 is a graph showing the result of X-ray diffraction of silicon (Si);

FIG. 4 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 311 peak of Si in FIG. 3;

FIG. 5 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 400 peak of Si in FIG. 3;

FIG. 6 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 331 peak of Si in FIG. 3;

FIG. 7 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 422 peak of Si in FIG. 3;

FIG. 8 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 511 peak of Si in FIG. 3;

FIG. 9 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 440 peak of Si in FIG. 3;

FIG. 10 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 531 peak of Si in FIG. 3;

FIG. 11 is a graph showing experimental values and a peak position by theoretical calculation: an enlarged vicinity of a 620 peak of Si in FIG. 3;

FIG. 12 is a graph showing a relation between the experimental peak positions and the theoretical ones determined from the eight peaks in FIGS. 4 to 11, and a correction formula of a systematic error, R: a correlation coefficient;

FIG. 13 is a graph showing experimental values before and after angle corrections: an enlarged 311 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 14 is a graph showing experimental values before and after angle corrections: an enlarged 222 peak of a calcia-stabilized zirconia in FIG. 2;

FIG. 15 is a graph showing experimental values before and after angle corrections: by enlarging 400 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 16 is a graph showing experimental values before and after angle corrections: an enlarged 331 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 17 is a graph showing experimental values before and after angle corrections: an enlarged 420 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 18 is a graph showing experimental values before and after angle corrections: an enlarged 422 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 19 is a graph showing experimental values before and after angle corrections: an enlarged 333 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 20 is a graph showing experimental values before and after angle corrections: an enlarged 440 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 21 is a graph showing experimental values before and after angle corrections: an enlarged 531 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 22 is a graph showing experimental values before and after angle corrections: an enlarged 442 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 23 is a graph showing experimental values before and after angle corrections: an enlarged 620 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 24 is a graph showing experimental values before and after angle corrections: an enlarged 533 peak of the calcia-stabilized zirconia in FIG. 2;

FIG. 25 is a graph showing the change of the lattice constant of calcia-stabilized zirconia after it is mixed with the other ingredients, and the friction material is formed: “single phase” stand for “before the formation”; “in friction materials”, “after the formation”;

FIG. 26 is a graph showing the change of friction coefficient after a high load friction test: the average friction coefficient during the second effectiveness test and that during the final inspection;

FIG. 27 is a graph showing the change of the lattice constant after a series of friction tests including the second effectiveness test and the final inspection;

Claims

1. A friction material comprising: a matrix fiber;a binder;a filler; anda stabilized zirconia having a lattice constant in a range from 99.93 to 99.95% as compared with a lattice constant of a single crystal of stabilized zirconia.

2. The friction material according to claim 1, wherein the stabilized zirconia is a calcia-stabilized zirconia having a lattice constant in a range from 5.1253 to 5.1263 Å.

3. A friction material comprising: a matrix fiber;a binder; anda filler, wherein a stabilized zirconia having a lattice constant in a range from 99.95 to 99.97% as compared with a lattice constant of a single crystal of stabilized zirconia is utilized as a compound in the filler.

4. The friction material according to claim 3, wherein the stabilized zirconia is a calcia-stabilized zirconia having a lattice constant in a range from 5.1263 to 5.1275 Å.

5. A method of manufacturing a friction material comprising: uniformly mixing a matrix fiber, a binder, and a filler; andmolding a mixture of the matrix fiber, the binder, and the filler under heating and pressure,wherein a stabilized zirconia having a lattice constant in a range from 99.95 to 99.97% as compared with a lattice constant of a single crystal of stabilized zirconia is utilized as a compound in the filler.

6. The method according to claim 5, wherein the stabilized zirconia is a calcia-stabilized zirconia having a lattice constant in a range from 5.1263 to 5.1275 Å.