Friction Brake Body for a Friction Brake, Friction Brake and Method for Producing a Friction Brake Body

Abstract

A friction brake body for a friction brake of a motor vehicle, in particular a brake disk, includes a base body made in particular from gray cast iron and having at least one wear resistant layer formed on a friction contact surface of the base body. The wear resistant layer is made from ferritic-austenitic steel and includes an incorporated hard material particle, in particular finely distributed hard material particle.

Claims

1. A friction brake element for a friction brake of a motor vehicle, comprising: a main element having a frictional contact surface; and at least one antiwear layer disposed on the frictional contact surface, the at least one antiwear layer formed of ferritic-austenitic steel and having embedded hard material particles.

2. The friction brake element as claimed in claim 1, wherein the at least one antiwear layer comprises chromium and/or nitrogen in order to increase the corrosion resistance.

3. The friction brake element as claimed in claim 1, wherein the hard material particles have an average particle size of less than 50 μm.

4. The friction brake element as claimed in claim 1, wherein the hard material particles include carbides, oxides, nitrides or borides.

5. The friction brake element as claimed in claim 1, wherein a proportion of hard material particles is less than or equal to 70% by volume of the at least one antiwear layer.

6. The friction brake element as claimed in claim 1, further comprising: an intermediate layer composed of pure ferritic-austenitic steel disposed between the at least one antiwear layer and the main element.

7. A friction brake for a motor vehicle, comprising: at least one brake disk comprising: a main element having a frictional contact surface; and at least one antiwear layer disposed on the frictional contact surface, the at least one antiwear layer formed of ferritic-austenitic steel and having embedded hard material particles; and at least one movable brake pad assigned to the brake disk.

8. A process for producing a friction brake element for a friction brake of a motor vehicle comprising: forming a main element with at least one antiwear layer forming a frictional contact surface, the at least one antiwear layer formed of ferritic-austenitic steel having embedded hard material particles.

9. The process as claimed in claim 8, wherein the forming of the main element further comprises applying the at least one antiwear layer to the main element by laser buildup welding or thermal spraying.

10. The process as claimed in claim 8, wherein the forming of the main element further comprises alloying the at least one antiwear layer is alloyed with chromium and/or nitrogen.

11. The process as claimed in claim 8, wherein the forming of the main element further comprises finely distributing the hard material particles in the at least one antiwear layer (5).

12. The process as claimed in claim 8, wherein the hard material particles have an average particle size of less than 50 μm.

13. The process as claimed in claim 8, wherein the hard material particles include carbides, oxides, nitrides or borides.

14. The process as claimed in claim 8, further comprising: applying an intermediate layer composed of pure ferritic-austenitic steel to the main element before application of the at least one antiwear layer.

15. The process as claimed in claim 8, further comprising: mechanically pretreating the main element before application of the at least one antiwear layer.

16. The process as claimed in claim 8, wherein the friction brake element is a brake disk.

17. The process as claimed in claim 8, wherein the main element is formed of gray cast iron.

18. The friction brake element as claimed in claim 1, wherein the friction brake element is a brake disk.

19. The friction brake element as claimed in claim 1, wherein the main element is formed of gray cast iron.

20. The friction brake element as claimed in claim 1, wherein the embedded hard material particles are finely distributed hard material particles.

Description

[0019] Further advantages and preferred features and combinations of features are derived, in particular, from the above description and also from the claims. The invention will be explained in more detail below with the aid of the drawing. The figures show:

[0020] FIG. 1 an advantageous friction brake element in a simplified perspective view,

[0021] FIG. 2 a detailed sectional view of the friction brake element and

[0022] FIG. 3 a flow diagram to explain an advantageous process for producing the friction brake element.

[0023] FIG. 1 shows, in a simplified depiction, a friction brake element 1 configured as brake disk 2 for a friction brake, which is not shown in more detail here, of a motor vehicle. The friction brake element 1 has a main element which is made of gray cast iron and has an annular configuration. A brake disk chamber which is optionally present on the brake disk 2 is not shown in FIG. 1.

[0024] On each of its two faces, the main element 3 has an annular frictional contact surface 4 which is formed by an antiwear layer 5 on the main element 3. During the intended use of the friction brake element 1, the antiwear layer 5 forms the contact partner of at least one movable brake lining or brake pad of the friction brake which can be pressed against the brake disk to effect frictional braking. Owing to the relative movement of brake disk and brake pad during braking, abrasion of the friction brake element 1 arises at the frictional contact surface 4. This abrasion leads firstly to wear of the friction brake element 1 and secondly to brake dust which can get into the surroundings.

[0025] To increase the wear and corrosion resistance and also the resistance to crack formation, the antiwear layer 5 is made of a ferritic-austenitic steel 6 and has, in particular, finely distributed, embedded hard material particles 7, which are indicated in simplified form by dots in FIG. 1.

[0026] In the present working example, the antiwear layer 5 has a plurality of sublayers. FIG. 2 shows in relation to this a detailed sectional view of the friction brake element 1 in the region of the frictional contact surface 4. The antiwear layer 5 forms a surface layer of the friction brake element 1. In the present working example, an intermediate layer 8 composed of pure ferritic-austenitic steel is additionally present between the antiwear layer 5 containing hard material particles 7.

[0027] Ferritic-austenitic steels display excellent cracking resistance. In addition, cracks forming in the antiwear layer 5 are stopped by the intermediate layer 8, so that cracks in the antiwear layer 5 cannot extend into the main element 3.

[0028] The corrosion resistance of the antiwear layer 5 is preferably increased by alloying-in of chromium and/or nitrogen. The wear resistance or abrasion resistance at the frictional contact surface 4 is increased by the hard material particles present in the antiwear layer 5. The hard material particles 7 preferably have an average particle size of less than 50 μm to this end. Carbides, oxides, nitrides or borides, in particular, are provided as hard material particles 7. The proportion of hard material in the antiwear layer 5 is preferably not more than 70% by volume so that mismatching of the coefficients of thermal expansion between layer and main element and the stresses resulting therefrom in the friction brake element 1 do not become too high when braking is carried out.

[0029] FIG. 3 is intended to explain an advantageous process for producing the friction brake element 1 by means of a flow diagram. In a first step S1, the main element 3, which is in particular made of gray cast iron, is provided. In a subsequent step S2, at least one face of the main element 3 is pretreated mechanically, for example by means of grinding, to set a defined roughness.

[0030] In the following optional step S3, the intermediate layer composed of pure ferritic-austenitic steel is applied to the main element 3. Here, the intermediate layer 8 is preferably applied to the main element 3 by laser buildup welding or by means of thermal spraying processes.

[0031] The actual antiwear layer 5 is subsequently applied to the main element 3 or to the intermediate layer 8 in a step S4, with the hard material particles 7 being applied simultaneously with the matrix phase of ferritic-austenitic steel to the main element 3 or to the intermediate layer 8.

[0032] Finally, the finished friction brake element 1 is obtained in a step S5, with the surface of the antiwear layer 5 optionally being mechanically after-treated, in particular ground, in order to ensure a desired geometry and roughness for interaction with the assigned brake lining and/or brake pad of the friction brake.