Coatings for brake discs, method for reducing wear and associated brake disc

Patent metadata

Field	Value
Publication number	US-11614137-B2
Application number	US-202017128259-A
Country	US
Kind code	B2
Filing date	Dec 21, 2020
Priority date	Dec 21, 2020
Publication date	Mar 28, 2023
Grant date	Mar 28, 2023

Abstract

Brake pads are prepared using a LS (Low Steel) or NAO (Non-Asbestos Organics) type friction material formulation and at least one friction surface of a brake disc intended to cooperate in use with a brake pad that is coated with an anti-wear and anti-corrosion coating with adequate plasticity in order to have a reduced propensity to form micro-cracks under conditions of tribo-mechanical stress, chosen from the amongst the group consisting in: particles of chromium carbide (Cr3C2) dispersed within a metallic matrix consisting of an alloy of NiCr; particles of a combination of several metallic materials in order to create a metallic compound consisting of an alloy of FeNiCrMoSiC (iron-nickel-chromium-molybdenum-silicon-carbon).

First claim

The invention claimed is:

1. An anti-wear and anti-corrosion coating for a brake disc comprising:
a single layer of a material comprising a metallic matrix constituted by a chromium-nickel austenitic steel and composed of an alloy of FeNiCrMoSiC (iron-nickel-chromium-molybdenum-silicon-carbon), wherein
the anti-wear and anti-corrosion coating is applicable to at least one friction surface of the brake disc configured to cooperate in use with a braking element,
the anti-wear and anti-corrosion coating is adapted to be applied by means of thermal spray, and
the anti-wear and anti-corrosion coating has a plasticity such as to have a reduced propensity to form micro-cracks under conditions of tribo-mechanical stress.

2. The anti-wear and anti-corrosion coating according to claim 1 , wherein the particles of chromium carbide or the austenitic steel alloy of composition FeNiCrMoSiC still in form of metallic particle of the single alloy components are applied by thermal spray by means of High Velocity Oxygen Fuel(HVOF) technology.

3. The anti-wear and anti-corrosion coating according to claim 1 , wherein the anti-wear and anti-corrosion coating has a thickness between 20 and 400 micrometers.

4. The anti-wear and anti-corrosion coating according to claim 1 , wherein the anti-wear and anti-corrosion coating has, after thermal spray coating and grinding, a surface roughness between 0.05 and 2 micrometers.

5. A vehicle brake system comprising:
an element to be braked, the element to be braked comprising a brake disc or a drum made from cast iron or steel; and
at least one braking element comprising a brake shoe or a pad, suitable for cooperating by friction with the element to be braked, the element to be braked having at least one friction surface configured to cooperate with the at least one braking element and the at least one friction surface covered with an anti-wear and anti-corrosion coating, wherein the anti-wear and anti-corrosion coating:
comprises a single layer of a material comprising a metallic matrix constituted by a chromium-nickel austenitic steel and composed of an alloy of FeNiCrMoSiC (iron-nickel-chromium-molybdenum-silicon- carbon);
is applicable to at least one friction surface of the brake disc configured to cooperate in use with a braking element;
is adapted to be applied by means of thermal spray; and
has a plasticity such as to have a reduced propensity to form micro-cracks under conditions of tribo-mechanical stress.

6. The vehicle brake system according to claim 5 , wherein the braking element comprises at least one friction material block configured to cooperate with the element to be braked, the friction material being of the LS (Low Steel) or NAO (Non Asbestos Organics) type.

7. The vehicle brake system according to claim 5 , wherein the particles of chromium carbide or the austenitic steel alloy of composition FeNiCrMoSiC still in form of metallic particle of the single alloy components are applied by thermal spray by means of High Velocity Oxygen Fuel(HVOF) technology.

8. The vehicle brake system according to claim 5 , wherein the anti-wear and anti-corrosion coating has a thickness between 20 and 400 micrometers.

9. The vehicle brake system according to claim 5 , wherein the anti-wear and anti-corrosion coating has, after thermal spray coating and grinding, a surface roughness between 0.05 and 2 micrometers.

10. A method for the simultaneous reduction in wear of a brake disc and associated brake pads, the method comprising:
preparing one or more brake pads using an LS (Low Steel) or NAO (Non Asbestos Organics) type friction material formulation;
covering at least one friction surface of a brake disc intended to cooperate in use with the one or more brake pads with an anti-wear and anti-corrosion coating with plasticity such as to have a reduced propensity to form micro-cracks under conditions of tribo-mechanical stress, wherein the anti-wear and anti-corrosion coating comprises an alloy of FeNiCrMoSiC (iron- nickel-chromium-molybdenum-silicon-carbon); and
coupling together the prepared one or more brake pads and the brake disc.

11. The method according to claim 10 , wherein the anti-wear and anti-corrosion coating is applied by means of the HVOF (High Velocity Oxygen Fuel) thermal spray technology.

12. The method according to claim 10 , wherein the one or more brake pads, made with a friction material belonging to the copper-free family, are coupled together with an anti-wear and anti-corrosion coating coated on at least one friction surface of the brake disc comprising particles of chromium carbide (Cr3C2) dispersed within a metallic matrix made of an alloy of NiCr or of a chromium-nickel austenitic steel.

13. The method according to claim 10 , wherein the particles are obtained from a combination of metallic materials in order to create a compound constituted by an alloy of FeNiCrMoSiC (iron-nickel-chromium-molybdenum-silicon-carbon).

Assignees

• Itt Italia Srl

Inventors

• Sin Xicola Agustin
• Vannucci Francesco
• Ansaloni Simone

Classifications

• F16D69/026

  containing fibres · CPC title

• F16D2200/0021

  Steel · CPC title

• F16D2200/0013

  Cast iron · CPC title

• F16D65/127 Primary

  characterised by properties of the disc surface; Discs lined with friction material · CPC title

• F16D2200/0017

  corrosion-resistant · CPC title