JPS62146280A - Disk rotor and its manufacture - Google Patents

Abstract

PURPOSE:To efficiently manufacture a disk rotor superior in rust resistance, by degraphitization treating the disk rotor composed of flake graphite cast iron remove flake graphite near by the surface and impregnating a zinc into obtd. pore. CONSTITUTION:Raw material of disk rotor prepd. by casting while using flake graphite cast iron is machined to a prescribed dimension to obtain the disk rotor 1 having a prescribed shape. Next, the rotor 1 is fed into treating furnace and heated to 850-950 deg.C favorably, in carburization atmosphere of CO, H2, N2 where carbon potential becomes <=Acm line, degraphitization treatment is carried out to remove flake graphite near by the rotor 1 surface and the pore 2 is formed. Next, the rotor 1 after the treatment is dipped in molten zinc bath and pressure is applied to impregnate the zinc 3 into the pore 2. In this way, rust resistance of the rotor 1 is improved without deteriorating productivity, resistances for wear and friction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disc rotor (brake disc) used in a disc brake and a method for manufacturing the same.

[Conventional technology]

Disc brakes are widely used as brakes for automobiles and the like. One of the components of this disc brake is the disc rotor, which is a disc-shaped part against which pads are pressed to perform a braking action on the disc brake.

This disc rotor is a relatively large component, and its main body has conventionally been manufactured using metals such as cast iron and steel, but generally it is mainly made of flake graphite cast iron (gray cast iron: JIS F
e12-25) are used.

[Problem that the invention seeks to solve]

Incidentally, in recent years, in cold regions, snow-melting agents mainly composed of salts have been frequently sprayed to prevent road surfaces from freezing. However, since flake graphite cast iron does not have sufficient rust resistance, there is a problem in that rust is likely to occur under such conditions.

Therefore, there has been a desire for a device to improve the rust resistance without impairing the wear resistance and friction resistance of flaky graphite cast iron.

[Means for solving problems]

The above problem is solved by the disc rotor and manufacturing method thereof of the present invention, which will be described below.

That is, the disc rotor of the present invention is made of flake graphite cast iron, and is characterized in that the pores near the surface of the disc rotor are impregnated with zinc.・－・－・－First
In addition, the method for manufacturing a disc rotor of the present invention involves manufacturing a disc rotor rough material by casting using flake graphite cast iron, shaping it into a predetermined shape by machining, and then degraphitizing the disc rotor material near the surface of the disc rotor. It is characterized by removing the flaky graphite and impregnating the resulting pores with zinc. −・−
-Second Invention In the present invention, flake graphite cast iron is used as the material for the disc rotor body, and is usually produced by casting.

Near the surface of this disc rotor, degraphitization treatment,
Holes are formed by an appropriate method such as etching.

As the degraphitization treatment, a method such as heating the disc rotor to 850° C. to 950° C. in a carburizing atmosphere of carbon monoxide, hydrogen, and nitrogen where the carbon potential is below the Acm line can be used.

Zinc is impregnated into the pores formed on the surface of the disc rotor by degraphitization treatment or the like. This zinc impregnation can be achieved by simply immersing the disc rotor in molten zinc, but in order to achieve sufficient impregnation, it is desirable to apply pressure or reduce the pressure of the disc rotor.

[Effect]

According to the present invention, since the pores formed on the surface of the disc rotor are impregnated with zinc, the impregnated zinc is coated on the disc rotor surface every time the brake is used. The zinc coated on the surface of the disc rotor always maintains the rust-preventing effect, and even in cold regions where snow-melting agents and the like are sprayed, a sufficient rust-resistant effect is achieved.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

Here, FIG. 1 is a schematic configuration diagram of a disc rotor according to an example of the present invention, FIG. 2 is an enlarged view of the X section in FIG. 1, and FIG. 3 is a diagram of a disc rotor obtained in the present invention and a comparative example. It is a graph showing rust test results.

First, using flake graphite cast iron (JIS Fe12),
A disc rotor 1 with an outer diameter of 250 m was cast. The surface of the obtained disc rotor 1 was machined to a predetermined size. As a result, the disc rotor 1 shown in outline in Fig.
was gotten. Subsequently, the product was placed in a processing furnace, and after replacing the inside of the furnace with propane decomposition endothermic gas having a carbon potential of 0.4%, degraphitization treatment was performed at 900° C. for 8 hours. The degraphitized disc rotor was placed in a crucible of 500
The disc rotor was immersed in a pure zinc molten bath maintained at ℃, and the pure zinc molten bath was pressurized with argon gas at lOkg-f/csA. By removing this, a disc rotor A was obtained in which the pores 2 formed by the degraphitization treatment were impregnated with zinc 3, as shown in FIG.

(First Comparative Example) The difference from the example is that the surface of the disc rotor was coated with zinc without being subjected to degraphitization treatment.
Disc rotor B was manufactured in substantially the same manner as in the example except for the above.

(Second Comparative Example) The difference from the example is that the disc rotor was cast and finished as a finished product without being subjected to degraphitization treatment or zinc coating, and other aspects were substantially implemented. A disc rotor C was manufactured in the same manner as in the example.

(Comparative Test) An evaluation test was conducted under the following conditions using disc rotors A, B, and C obtained in Examples and Comparative Examples.

That is, a semi-metallic pad was used as a mating material, the pad was braked 20 times at a deceleration of 0.5 G at a speed of 100 km/H, and then removed from the vehicle and subjected to a rust test. Similarly, a rust test was also conducted on those that had been braked 200 times and those before the braking test.

In the rust test, 5% saline solution at 50°C was continuously sprayed onto the sliding surface of the disc rotor for 10 hours, and then dried for 2 hours.
After repeating the process four times, the rust on the surface of the disc rotor was scraped off with a scraper, and the weight was measured. The results are shown in FIG.

As is clear from Figure 3, disc rotor C, which has not been treated in any way, has a large amount of rust both before and after the brake test, and disc rotor B, which is simply coated with zinc, has poor rust resistance before the brake test. Although the results were as good as in this example, the amount of rust generated was comparable to that of disk rotor A after the brake test. On the other hand, it can be seen that the disc rotor A of this example has good rust resistance both before and after the brake test.

In addition, various wear characteristics such as wear resistance, wear coefficient, and thermal stability were tested and investigated for disc rotors A and C, but no particular difference was found between the two.

Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but includes various embodiments within the scope of the claims.

〔Effect of the invention〕

From the above, according to the disc rotor of the present invention, manufacturability,
The wear resistance, abrasion characteristics, etc. are maintained at the same level as conventional flake graphite cast iron disc rotors, while the rust resistance is significantly improved. Further, according to the method for manufacturing a disc rotor of the present invention, the above-mentioned disc rotor having excellent rust resistance can be efficiently manufactured.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a disc rotor according to an example of the present invention, Fig. 2 is an enlarged view of the X section in Fig. 1, and Fig. 3 is a rust test result of a disc rotor obtained in the present invention and a comparative example. This is a graph showing. 1---------Disc rotor 2------Vacancy 3----Zinc Applicant Toyota Motor Corporation Fig. 1/3 cars\2 empty λ

Claims (3)

[Claims] (1) A disc rotor made of flaky graphite cast iron, characterized in that voids near the surface of the disc rotor are impregnated with zinc. (2) A method for manufacturing a disc rotor made of flaky graphite cast iron, which involves producing a disc rotor rough material by casting using flaky graphite cast iron, shaping it into a predetermined shape by machining, and then degraphitizing it. Remove flaky graphite near the disc rotor surface,
A method for manufacturing a disc rotor, comprising impregnating the resulting pores with zinc. (3) In claim 2, the disc rotor is heated at 850°C to 950°C in a carburizing atmosphere of carbon monoxide, hydrogen, and nitrogen where the carbon potential is below the Acm line.
1. A method for manufacturing a disc rotor, characterized in that degraphitization treatment is performed by heating to .