JP3262365B2 - Manufacturing method of brake disc - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a lightweight aluminum alloy brake disc used in vehicles such as railways and automobiles, and more particularly to a method of using a metal-containing alloy powder which is more active than aluminum to reduce the adhesion of a flame sprayed coating. The present invention relates to a method for manufacturing an improved brake disk.

[0002]

2. Description of the Related Art Since a brake disk is a component that is frequently rubbed against a brake lining which is a mating material, a surface slid on the brake lining must have excellent heat resistance and wear resistance. Is required.

[0003] Conventional brake discs are mainly made of cast iron or stainless steel, and those utilizing the wear resistance and heat resistance of the material are used. However, the specific gravity of an iron-based brake disc is as high as 7.2 to 7.8, and it is not possible to cope with a reduction in the weight of the brake disc.

[0004] For this reason, materials have been changed from iron-based to aluminum alloy-based in response to a demand for a lighter brake disk. When this aluminum alloy is used, there is a problem that heat resistance and wear resistance are extremely poor.

Therefore, a coating is formed by spraying a wear-resistant material onto a brake disk or an aluminum alloy having improved heat resistance and wear resistance by dispersing ceramic particles and the like in an aluminum alloy, and forming a coating only on the surface. Brake discs having properties equivalent to those of materials have been proposed.

However, when manufacturing a brake disc using an aluminum composite material in which ceramic particles and the like are dispersed, machining such as cutting and grinding of extremely hard ceramic particles is difficult, and the processing cost becomes extremely high. .

On the other hand, when an abrasion-resistant material is formed on the surface of an aluminum alloy, there is a problem in that thermal spraying in the atmosphere does not have a high adhesion force, so that peeling occurs. That is,
In flame spraying on an aluminum alloy, oxygen in the atmosphere lowers the adhesion, so it is necessary to improve the adhesion by using a reduced pressure plasma spraying method. However, this low-pressure plasma spraying method has a problem that equipment cost and running cost are much higher than flame spraying.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the sliding surface has good abrasion resistance and heat resistance, and is excellent in economy and weight reduction. An object of the present invention is to provide a method of manufacturing a brake disc in which the adhesion is improved even by simple flame spraying.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a brake disk made of an aluminum alloy containing 0.2 to 5.0 wt% of lithium and / or magnesium.
This is achieved by applying a flame-sprayed nickel-aluminum-based alloy powder to form a sprayed coating without melting the applied metal after applying the contained alloy powder.

[0010]

Hereinafter, the production method of the present invention will be described in more detail. In the present invention, as a material of the brake disc,
Aluminum alloys are used to reduce the weight. The composition of the aluminum alloy is not particularly limited. As described above, in the present invention, since the brake disk body is formed of an aluminum alloy, the weight can be reduced by about 65% when compared only with the specific gravity of the brake disk, and the thermal conductivity is 7%. The value is about twice as high, and the heat dissipation can be improved.

On the other hand, the modulus of elasticity of an aluminum alloy is about 35% of that of cast iron, so that a thickness about 1.5 times is required to obtain cast iron-grade strength. Even taking this into account, the weight of the aluminum alloy brake disc is
The weight can be reduced by about 50% as compared with the conventional iron-based brake disc.

In the present invention, an alloy powder containing 0.2 to 5.0 wt% of lithium and / or magnesium is applied to the sliding surface of the aluminum alloy brake disk. Specific alloy powders include, for example, aluminum-lithium and / or magnesium, zinc-lithium and / or magnesium, aluminum-silicon-lithium and / or magnesium, aluminum-copper-lithium and / or magnesium, etc. Aluminum-lithium and / or magnesium are most preferred in terms of adhesion between the aluminum alloy and the thermal spray coating. The content of lithium and / or magnesium in these alloy powders is desirably 0.2 to 5.0% by weight.

The method of applying the alloy powder containing 0.2 to 5.0 wt% of lithium and / or magnesium to the sliding surface of the brake disk is not particularly limited, and may be merely sprayed on the sliding surface, You may apply | coat using a binder. The coating thickness at this time is desirably about 5 to 30 μm.

In the present invention, the nickel-aluminum-based alloy powder is flame-sprayed on the surface coated with the alloy powder containing 0.2 to 5.0 wt% of lithium and / or magnesium without melting the coated metal. To form a thermal spray coating excellent in heat resistance and wear resistance. The flame spraying is a simple thermal spraying method using a flame of oxygen / acetylene gas combustion usually used in a thermal spraying method.

The nickel-aluminum base alloy powder used here is selected from molybdenum, chromium, iron, boron, silicon, copper, aluminum oxide, titanium dioxide, dichromium trioxide, magnesium oxide, zirconium oxide and nickel oxide. It may contain at least one kind,
The content is preferably 1 to 10% by weight.

[0017] If necessary, the above-mentioned lithium and / or magnesium may be added to the sprayed coating in an amount of 0.
An alloy powder containing 2 to 5.0 wt% may be applied, and a thermal spray coating may be formed by flame spraying to form a laminated thermal spray coating.

In this way, a low-cost and lightweight brake disk having excellent wear resistance and heat resistance of the sliding surface can be obtained.

[0019]

EXAMPLES Hereinafter, the present invention will be specifically described based on examples and the like.

Example 1 A plate-like test piece of aluminum alloy 5083 (size: 10 mm
× 100 mm × 100 mm), a 1.0% by weight lithium-aluminum alloy powder was sprayed thereon to a coating thickness of 10 μm.

Next, 6.0% by weight chromium-7.0% by weight aluminum-
A sprayed coating of nickel alloy powder was formed.

The adhesion between the obtained thermal spray coating and the plate-shaped test piece was measured by the following method. The results are shown by comparing the used lithium and / or magnesium with 0.2 to 5.0 w.
Table 1 shows the composition, the coating thickness, and the spraying method of the alloy powder containing t%.

[Adhesion Test Method] An adhesion tester shown in FIG. 1 was used. In the figure, 1 is a plate-shaped test piece of an aluminum alloy, 2 is a thermal spray coating, 3 is an adhesive, 4 is a jig, and 5 is a material fixing jig. The bonding surface uses an aluminum jig 4 having a diameter of 20 mm. The bonding method is to bond the bottom of the jig 4 and the thermal sprayed coating 2 using a two-part type strong adhesive 3 and hold it indoors for at least 24 hours. An adhesion test was performed, and the breaking force of the contact surface was defined as the adhesion force.

Examples 2 to 16 As shown in Table 1, the same procedure as in Example 1 was carried out except that the type and coating thickness of the alloy powder containing 0.2 to 5.0 wt% of lithium and / or magnesium were changed. A thermal spray coating was formed on the plate-like test piece. The adhesion was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 17 A plate-like test piece was prepared in the same manner as in Example 1 except that 5.0% by weight of molybdenum-7.0% by weight of aluminum-nickel alloy powder was used as the nickel-aluminum-based alloy powder for flame spraying. Then, a thermal spray coating was formed. The adhesion was measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 Lithium and / or magnesium were added at 0.2 to 5.0.
A thermal spray coating was formed on a plate-like test piece by flame spraying in the same manner as in Example 1 except that the alloy powder containing wt% was not applied. The adhesion was measured in the same manner as in Example 1, and the results are shown in Table 1.

[0027]

[Table 1]

As is clear from the results in Table 1, Example 1
No. 17 to 17 have improved adhesion as compared with Comparative Example 1.

Test Example 1 (Wear Test) The wear amount was measured by the following test materials and test methods.

(1) Test Material Treated material of the present invention: 1.0 wt% lithium-aluminum alloy powder was sprayed on a test piece of aluminum alloy 5083 having a diameter of 55 mm and a thickness of 5 mm so as to have a coating thickness of 10 μm. Next, flame spraying on this spray surface
A thermal spray coating of 6.0% by weight chromium-7.0% by weight aluminum-nickel alloy powder was formed. Aluminum alloy + reduced pressure plasma: 55mm diameter x
50T for aluminum alloy 5083 specimen with thickness of 5mm
Plasma spraying was performed under reduced pressure in an argon atmosphere under an orr reduced pressure to form a sprayed coating of 6.0% by weight chromium-7.0% by weight aluminum-nickel alloy powder. Cast iron: 55 mm diameter x 5 mm thick cast iron (FC2
5) was used. Aluminum alloy material: diameter 55mm x thickness 5mm
Was used as it was.

(2) Test Method A test was performed using a pin-on-disk tester under the following conditions. Lining test piece of mating material: diameter 8 mm x length 15
mm of the current copper-based sintered alloy was used. Lubrication: No lubrication Friction speed: 6 m / sec Contact surface pressure: 0.5 MPa Friction distance: 3 Km (weight was measured every 0.5 Km to determine the amount of wear)

(3) Test Results The results are shown in FIG. As shown in FIG. 2, the amount of wear is
It is about 1/5 that of cast iron, which is currently used, and it is understood that it is excellent as in the case of using the reduced pressure plasma method.

Test Example 2 (Thermal Stability Test) In order to evaluate the effect of thermal shock due to frictional heat on the sprayed coating, the thermal stability of the sprayed coating was measured by the following test materials and test methods.

(1) Test Material Treated material of the present invention: The sample obtained in Example 1 was used. Reduced pressure plasma material: 50 pieces were added to the test piece used in Example 1.
Under reduced pressure of Torr, reduced pressure plasma spraying was performed in an argon atmosphere to form a sprayed coating of 6.0% by weight chromium-7.0% by weight aluminum-nickel alloy powder. Flame sprayed material: The sample obtained in Comparative Example 1 was used.

(2) Test Method Each test material is kept at 450 ° C. for one hour, and then rapidly cooled to 20 ° C. water. This operation was repeated 200 times, and the state of peeling of the sprayed coating was observed.

(3) Test results The results are shown below. Treatment material of the present invention: not peeled Low-pressure plasma material: not peeled Flame sprayed material: large peeled

As described above, in the conventional flame spraying method,
Peeling of the coating is observed, but in the treatment method of the present invention, peeling of the coating is not seen as in the case of the reduced pressure plasma method, and it is understood that the thermal stability is excellent.

From the results of Test Examples 1 and 2, it can be seen that the brake disk obtained according to the present invention can sufficiently withstand use in terms of wear resistance and heat resistance.

[0039]

As described above, in the aluminum alloy brake disk obtained by the manufacturing method of the present invention, the sliding surface and the sprayed coating are firmly adhered.
The thermal spray coating does not peel off. Therefore, the sliding surface has high heat resistance and wear resistance, and the weight of the brake disk can be reduced. Further, since expensive equipment costs and running costs are not required as in the case of using the reduced pressure plasma spraying method, it is extremely economically advantageous.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an adhesion tester used in Examples and Comparative Examples.

FIG. 2 is a graph showing a relationship between a wear amount and a friction distance in Test Example 1.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-99447 (JP, A) JP-A-63-175986 (JP, A) JP-A-63-145761 (JP, A) JP-A-2- 57672 (JP, A) JP-A-51-83842 (JP, A) JP-A-58-164775 (JP, A) JP-A-62-253779 (JP, A) JP-A-1-240677 (JP, A) JP-A-62-60855 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16D 65/12 C23C 4/00

Claims (2)

(57) [Claims] An alloy powder containing 0.2 to 5.0 wt% of lithium and / or magnesium is applied to a sliding surface, and a nickel-aluminum-based alloy powder is applied to a frame without melting the applied metal. A method for manufacturing an aluminum alloy brake disc, which is sprayed. 2. The nickel-aluminum base alloy powder is at least one selected from molybdenum, chromium, iron, boron, silicon, copper, aluminum oxide, titanium dioxide, dichromium trioxide, magnesium oxide, zirconium oxide, and nickel oxide. The method for producing a brake disk according to claim 1, wherein the seed contains 1 to 10% by weight.