Method for producing brake disc, and brake disc

Abstract

To provide a method for producing a brake disc, by which a brake disc particularly excellent in wear resistance, temperature resistance and corrosion resistance is produced in an inexpensive and reliable manner.SOLUTION: A method for producing a brake disc comprises forming friction-resistant outer layers (10a, 10b) by spraying, a cold gas spraying method, a particle mixture on a base body (2) or on intermediate layers (12a, 12b) sprayed on the base body (2), where the particle mixture comprises 25-75 wt.% of a metal matrix material and 75-25 wt.% of a carbide material. The metal matrix material comprises an iron-based alloy, a nickel-based alloy, titanium, or a titanium alloy. The carbide material comprises tungsten carbide, titanium carbide, iron carbide, silicon carbide, chromium carbide, or niobium carbide.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a brake disk described in the preamble of claim 1 and a brake disk for a disk brake described in the preamble of claim 6.

Background Art

[0002] A brake disk used for a disk brake of a vehicle usually includes a base body having a friction surface formed on a side surface, and the base body is formed of gray cast iron, cast steel or cast aluminum. A base body made of a polymer material or a composite material is also known.

[0003] A disk brake includes a rotating brake disk and a brake pad attached to the periphery of the brake disk. A brake lining provided on the brake pad is pressed against the rotating brake disk, and frictional braking for suppressing the rotation of the brake disk by friction with the brake lining is utilized. The brake lining of the brake pad is pressed against the opposing friction surfaces on both sides of the rotating brake disk by mechanical force, hydraulic pressure or pneumatic pressure to normally achieve the braking action or deceleration of the vehicle. Single annular friction surfaces are formed on both sides of the brake disk. A multi-plate disk brake that uses the entire both side surfaces of the brake disk as opposing friction surfaces can also be used.

[0004] Due to the high frictional force generated during braking of the brake and the large amount of heat generated due to friction, known brake disks have a defect that a large amount of wear occurs and they gradually deteriorate. Known brake disks also have another drawback of being easily corroded.

[0005] For example, various coating methods are known for coating metal or resin processed products or other substrates with specific materials. One coating method is the cold gas spraying method (dynamic coating method, cold gas spraying method, metal particle adhesion method, dynamic metallization method, supersonic metal powder volume method). In the cold gas spraying method, the coating material is sprayed onto the substrate at very high speed, especially supersonic, and adheres to form a coating film. Along with the introduction of the coating material, a working gas heated to a maximum temperature of approximately 1200°C is supplied to the spray gun at high pressure. Next, the working gas is expanded and accelerated to supersonic speed in a convergence-divergence nozzle (Laval nozzle). At this time, the sprayed powder injected into the nozzle is accelerated to supersonic speed, and the sprayed powder adheres firmly to the substrate with high kinetic energy. Compared to other bonding methods, the sprayed material has the advantage of not welding or melting on the surface. [Overview of the project] [Problems that the invention aims to solve]

[0006] Therefore, the fundamental object of the present invention is to provide a method for manufacturing brake discs that have particularly excellent properties in terms of wear resistance, temperature resistance, and corrosion resistance, and that can be produced cost-effectively and with high reliability. Another object of the present invention is to provide brake discs that possess multiple excellent physical and chemical properties. [Means for solving the problem]

[0007] The problems of the present invention are solved by a method for manufacturing a brake disc having the features described in claim 1 of the present invention, and a brake disc having the features described in claim 6 of the present invention. Advantageous embodiments of the present invention are described in the dependent claims.

[0008] The brake disc manufacturing method of the present invention includes the step of forming a wear-resistant outer layer (wear-resistant outer surface layer) on a substrate or an intermediate layer formed by spraying a particle mixture onto a substrate by a cold gas spraying method, wherein the particle mixture consists of 25% to 75% by weight of a metal base material and 75% to 25% by weight of carbides. The metal base material consists of one material selected from iron-based alloys, nickel-based alloys, titanium, and titanium alloys.

[0009] The carbide consists of one material selected from tungsten carbide, titanium carbide, iron carbide, silicon carbide, chromium carbide, and niobium carbide.

[0010] The brake disc manufacturing method of the present invention forms a highly wear-resistant outer layer on a substrate or an intermediate layer formed by spraying onto a substrate. By employing a cold gas spraying method and a composite material combination, wear can be reduced to 99% of that of conventional brake discs.

[0011] The risk of peeling of the wear-resistant outer layer, which is formed on the substrate or intermediate layer and has high adhesion strength, is significantly reduced. The wear-resistant outer layer also has high corrosion resistance. The amount of heat transferred to the substrate by the cold gas blowing method is extremely small, and thermal deformation or thermal strain of the substrate is suppressed to a minimum or does not occur at all. By using iron-based alloys, titanium, or titanium alloys as the metal base material, the use of environmentally hazardous substances such as nickel or copper can be avoided. Because the physical properties of the wear-resistant outer layer can be improved, the substrate of an extremely high-performance disc brake can be formed from lightweight materials such as light metals, for example, and the weight of the brake disc can be significantly reduced. Furthermore, by combining the highly efficient cold gas blowing method with the particle mixture proposed in this invention, a very cost-effective brake disc manufacturing method of the present invention can be proposed.

[0012] An abrasion-resistant outer layer can be formed by a spraying method on an intermediate layer that is either directly sprayed onto the substrate of a brake disc used in the implementation of the present invention or pre-sprayed onto the substrate. In an advantageous embodiment of the present invention, an intermediate layer can be formed by spraying a granular (particulate) metal base material onto the substrate by a cold gas spraying method, and the granular metal base material is composed of one material selected from iron-based alloys, nickel-based alloys, titanium, and titanium alloys.

[0013] The intermediate layer can be formed using the same metal base material as the wear-resistant outer layer, but it may also be formed using a different metal base material. For example, the intermediate layer can be formed from an iron-based alloy, while the wear-resistant outer layer, i.e., the metal base material of the composite material, can be made from a nickel-based alloy, titanium, or titanium alloy. By selecting the material for the intermediate layer, depending on the substrate material and also on the material of the wear-resistant outer layer, particularly good adhesion can be achieved in the bonding between adjacent layers and in the bonding with the substrate.

[0014] In an advantageous embodiment of the present invention, the iron-based alloy used for the metal base material of the wear-resistant outer layer and / or intermediate layer contains 5% to 40% by weight of chromium, thereby achieving particularly favorable corrosion resistance.

[0015] In an advantageous embodiment of the present invention, the titanium alloy used as the metal base material for the wear-resistant outer layer and / or intermediate layer contains 5.5% to 6.75% by weight of aluminum and 3.5% to 4.5% by weight of vanadium, thereby enabling the formation of a particularly stable and highly heat-resistant wear-resistant outer layer and intermediate layer.

[0016] In an advantageous embodiment of the present invention, the abrasion-resistant outer layer or intermediate layer can be well adhered to the substrate by a process in which the region of the substrate to which the particle mixture forming the abrasion-resistant outer layer or the granular metal base material forming the intermediate layer is sprayed is roughened before spraying by mechanical means, chemical means, or laser irradiation.

[0017] The problem of the present invention is solved by a brake disc for a disc brake having a substrate and a wear-resistant outer layer formed on at least one surface of the substrate, wherein a friction surface is formed on the wear-resistant outer layer. The wear-resistant outer layer of the brake disc is composed of a composite material formed by spraying a particle mixture onto the substrate or an intermediate layer formed by spraying onto the substrate using a cold gas spraying method. The particle mixture consists of 25% to 75% by weight of a metal base material and 75% to 25% by weight of carbides. The metal base material consists of one material selected from the group consisting of iron-based alloys, nickel-based alloys, titanium, and titanium alloys. The carbides consist of one material selected from tungsten carbide, titanium carbide, iron carbide, silicon carbide, chromium carbide, and niobium carbide.

[0018] When the brake disc of the present invention is used, technical effects and advantages related to the brake disc manufacturing method can be achieved similarly.

[0019] It is preferable to form the whole or a part of the base body with cast steel, gray cast iron, cast aluminum, polymer material or composite material.

[0020] With reference to the accompanying drawings, exemplary embodiments of the present invention will be described in detail below. The drawings show the following.

Brief Description of the Drawings

[0021] [Figure 1] Cross-sectional view of the brake disc according to the first embodiment of the present invention [Figure 2] Enlarged cross-sectional view of detail II shown in FIG. 1 [Figure 3] Cross-sectional view showing the second embodiment of the present invention corresponding to FIG. 2

Mode for Carrying Out the Invention

[0022] FIG. 1 shows a cross-section of a brake disc 1 used for a disc brake of a vehicle such as an automobile, a truck, a motorcycle, a bicycle or a railway vehicle.

[0023] In the illustrated embodiment, the brake disc 1 includes a base body 2 having a cup-shaped central portion 3 and an annular disc 4 extending radially outward from the central portion 3.

[0024] The base body 2 of the illustrated embodiment 1 shows an integrally formed structure, but it may be composed of a plurality of parts. It is preferable to form the base body 2 with cast steel, gray cast iron, cast aluminum, polymer or composite material.

[0025] As is well known, the central portion 3 has a function of fixing the brake disc 1 to a rotating part such as a hub of a vehicle, for example.

[0026] The annular disc 4 extending radially outward from the central portion 3 is positioned within the main plane (extending radially outward from the central axis 5 of the brake disc 1). In the illustrated embodiment, the disc 4 is composed of a pair of parallel annular discs 6a, 6b connected to each other by a known method with a certain angle between them, by a plurality of thin plate-shaped connecting portions 7 (preferably connecting portions 7 regularly arranged at equal angular intervals in the circumferential direction of the brake disc 1). The brake disc 1 is cooled by cooling air passing through the free space formed between adjacent annular discs 6a, 6b.

[0027] The brake disc manufacturing method of the present invention can also be easily applied to multi-disc brakes.

[0028] Abrasion-resistant outer layers 10a and 10b are formed on both outer surfaces 9a and 9b of the disc 4 by spraying with a cold gas. In the cold gas spraying method, it is preferable to form both abrasion-resistant outer layers 10a and 10b with the same material, the same spraying method, and the same thickness. The lateral outer surfaces of the abrasion-resistant outer layers 10a and 10b form friction surfaces 11a and 11b. In the illustrated embodiment, the rotating abrasion-resistant outer layers 10a and 10b contact a pair of brake pads (not shown) to brake the rotating wheels of the vehicle. The brake provided on the vehicle comprises a brake caliper fixed to the vehicle, a pair of brake pads provided on both sides of the friction surfaces 11a and 11b of the brake disc 1, and a brake lining attached to the brake pads. The pair of brake pads are attached to the brake pad so as to be able to move forward and backward or move relative to each other. When the brakes are applied, the pair of brake pads supported by the brake caliper move toward each other, pressing the brake lining against the friction surfaces 11a and 11b of the wear-resistant outer layers 10a and 10b, generating the frictional force necessary for braking between the brake pads and the disc 4, thereby stopping the rotation of the wheel.

[0029] The wear-resistant outer layers 10a and 10b are composed of a composite material of a metal base material and carbides. In the present invention, it is preferable to use an iron-based alloy, nickel-based alloy, titanium, or titanium alloy having 5% to 40% by weight of chromium (which may or may not contain additional alloying components) as the metal base material, for example, 64 titanium (Ti-6Al-4V) having 5.5% to 6.75% by weight of aluminum and 3.5% of vanadium.

[0030] Carbides are composed of tungsten carbide, titanium carbide, iron carbide, silicon carbide, chromium carbide, or niobium carbide.

[0031] The composite material of the wear-resistant outer layers 10a and 10b is produced by a spraying method of a powder mixture or particle mixture consisting of 25% to 75% by weight of a metal base material and 75% to 25% by weight of carbides.

[0032] The surfaces of the side surfaces 9a and 9b of the disc 4 can be treated using an appropriate method before coating to ensure that the wear-resistant outer layers 10a and 10b are well formed on the disc 4. In particular, surface roughening methods for the side surfaces 9a and 9b can be used. Surface roughening can be achieved by mechanical roughening, chemical pretreatment, laser beam treatment structuring, etc.

[0033] Figure 3 shows a second embodiment of the present invention, corresponding to the brake disc portion in Figure 2, which shows the first embodiment. For the configuration of the base body 2 of the second embodiment, which has the same configuration as the base body 2 of the first embodiment, please refer to the first embodiment.

[0034] In the second embodiment, unlike the first embodiment in which the wear-resistant outer layers 10a and 10b are formed by directly spraying onto the disc 4 of the base 2, intermediate layers 12a and 12b are formed on the side surfaces 9a and 9b of the disc 4 by a cold gas spraying method, and then the wear-resistant outer layers 10a and 10b are formed by spraying a particle mixture onto the intermediate layers 12a and 12b by a cold gas spraying method.

[0035] The two intermediate layers 12a and 12b can be formed in a similar manner. The intermediate layers 12a and 12b are composed of a metal matrix containing an iron-based alloy (preferably containing 5% to 40% chromium), a nickel-based alloy, titanium, or a titanium alloy (for example, titanium 64 (Ti6Al4V) containing 5.5% to 6.76% aluminum and 3.5% to 5.5% vanadium).

[0036] The metal base material of the intermediate layers 12a and 12b may be the same metal base material as the wear-resistant outer layers 10a and 10b, or it may be a different metal base material.

[0037] In the second embodiment as well, before spraying the two intermediate layers 12a and 12b, an appropriate pretreatment method for both sides 9a and 9b of the disc 4, particularly a method for roughening the surface, is suitable for the purpose of the present invention. This can be formed in the same manner as in the first embodiment.

Claims

1. A method for manufacturing a brake disc (1) having a base body (2) and an abrasion-resistant outer layer (10a, 10b) provided on at least one surface of the base body (2), wherein friction surfaces (11a, 11b) are formed on outer surfaces of the abrasion-resistant outer layers (10a, 10b), The method includes a step of spraying a particle mixture onto the surface of a substrate (2) or onto the surface of an intermediate layer (12a, 12b) formed on the substrate (2) by a cold gas spraying method to form an abrasion-resistant outer layer (10a, 10b), the particle mixture is composed of 25 wt% to 75 wt% of the metal matrix and 75 wt% to 25 wt% of the carbide; The metal base material is made of one material selected from an iron-based alloy, a nickel-based alloy, titanium, and a titanium alloy; and A method for manufacturing a brake disc, characterized in that the carbide is made of one material selected from tungsten carbide, titanium carbide, iron carbide, silicon carbide, chromium carbide, and niobium carbide.

2. a step of spraying a granular metal base material onto the surface of the substrate (2) by a cold gas spraying method to form an intermediate layer (12a, 12b); 2. The method for manufacturing a brake disc according to claim 1, wherein the granular metal base material is made of one material selected from the group consisting of an iron-based alloy, a nickel-based alloy, titanium, and a titanium alloy.

3. 3. The method for manufacturing a brake disc according to claim 1, wherein the iron-based alloy contains 5% to 40% by weight of chromium.

4. 2. The method of claim 1, wherein the titanium alloy contains 5.5 to 6.75 weight percent aluminum and 3.5 to 4.5 weight percent vanadium.

5. a step of spraying a granular metal base material onto a substrate (2) to form an intermediate layer (12a, 12b); a step of roughening the intermediate layer (12a, 12b) region on the substrate (2) formed by spraying the granular metal base material by mechanical treatment, chemical treatment or laser irradiation; and spraying the particle mixture onto the roughened area of ​​the intermediate layer (12a, 12b) to form the outer wear-resistant layer (10a, 10b).

6. A brake disc (1) for a disc brake, comprising a base (2) and an abrasion-resistant outer layer (10a, 10b) formed on at least one surface of the base (2), wherein friction surfaces (11a, 11b) are formed on the abrasion-resistant outer layer (10a, 10b), The abrasion-resistant outer layer (10a, 10b) is made of a composite material of a particle mixture sprayed by a cold gas spraying method onto the substrate (2) or onto the intermediate layer (12a, 12b) sprayed onto the substrate (2); the particle mixture comprises 25 wt% to 75 wt% of the metal matrix and 75 wt% to 25 wt% of the carbide; The metal base material is made of one material selected from an iron-based alloy, a nickel-based alloy, titanium, and a titanium alloy; A brake disc, wherein the carbide is made of one material selected from tungsten carbide, titanium carbide, iron carbide, silicon carbide, chromium carbide, and niobium carbide.

7. the intermediate layer (12a, 12b) is composed of a granular metal base material sprayed onto the substrate (2) at least primarily by a cold gas spraying method; 7. The brake disc according to claim 6, wherein the metal base material is made of one material selected from the group consisting of an iron-based alloy, a nickel-based alloy, titanium, and a titanium alloy.

8. 8. A brake disc according to claim 6 or 7, wherein the iron-based alloy contains 5% to 40% by weight of chromium.

9. 7. A brake disc according to claim 6, wherein the titanium alloy contains 5.5 to 6.75% by weight of aluminum and 3.5 to 4.5% by weight of vanadium.

10. 7. A brake disc according to claim 6, further comprising a step of roughening the areas of the substrate (2) onto which the particle mixture forming the outer wear-resistant layer (10a, 10b) is sprayed or the areas of the substrate (2) onto which the granular metal matrix forming the intermediate layer (12a, 12b) is sprayed by mechanical means, chemical means or laser light irradiation.

11. 7. A brake disc according to claim 6, wherein the substrate (2) is made entirely or partly of cast steel, grey cast iron, cast aluminium, polymer or composite material.

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