KR20070117241A - Brake drum for vehicle - Google Patents

Abstract

A brake drum for vehicle is provided to prevent deformation of the brake drum by improving tensile strength of a brake drum as compared with a conventional brake drum, and improve tensile strength and wear resistance of the brake drum at the same time by controlling contents of constituents of the brake drum. A brake drum for vehicle comprises: by weight percent, iron(Fe) as a principal component, and further comprises 3.3 to 3.7% of carbon(C), 1.3 to 2.5% of silicon(Si), 0.5 to 1.0% of manganese(Mn), 0.1% or less of phosphorous(P), 0.1% or less of sulfur(S), 1.2 to 2.0% of nickel(Ni), 0.3 to 0.6% of chromium(Cr), and 0.3 to 0.5% of molybdenum(Mo).

Description

Brake drum for vehicle

1 is a graph showing the wear test results between a brake drum for a vehicle and a conventional brake drum according to the present invention.

Figure 2 is a photograph illustrating the equipment for testing the amount of wear between the vehicle brake drum and the conventional brake drum according to the present invention.

3 is a schematic diagram illustrating a brake drum structure for a vehicle;

4 is a photograph illustrating a method of manufacturing a vehicle brake drum.

<Explanation of symbols for the main parts of the drawings>

1: drum brake 10: brake drum

20: Back Plate 30: Break Shoe

40: lining 50: wheel cylinder

The present invention relates to a brake drum for a vehicle, and more particularly, nickel (Ni), chromium (Cr), and at the same time to control the content of carbon (C), silicon (Si), manganese (Mn), the main components of the brake drum The invention relates to a brake drum for a vehicle in which molybdenum (Mo) is further added to increase tensile strength and improve wear resistance.

In general, a vehicle brake system is classified into a main brake used for deceleration during driving and a parking brake used for parking, and the main brake is configured to brake the hydraulic pressure generated by the operation of the brake pedal. Hydraulic brakes, hydraulic brakes designed to be used when a large braking force is required, such as large vehicles, and air brakes that generate braking force by using the pressure of compressed air. There is a drum type brake that generates a braking force by squeezing a brake shoe having a lining to a rotating brake drum from the inside.

Here, the general configuration of the drum-type brake (1) is, as shown in Figure 3, the brake drum 10 is installed on the wheel hub via a bolt to rotate with the wheel, and the back plate fixed to the axle ( 20), the cast iron brake shoe 30 provided on the back plate 20, and attached to the outer surface of the brake shoe 30 and in direct contact with the brake drum 10 of the brake drum 10 Lining 40, which is a friction material to stop rotation and change the kinetic energy into thermal energy, and the wheel cylinder 50 to compress the brake shoe 30 to the brake drum 10 through the hydraulic pressure generated from the master cylinder. Etc.

Therefore, when the driver steps on the brake pedal while driving, the hydraulic pressure generated in the master cylinder is transmitted to the wheel cylinder 50, and the brake shoe 30 is rotated together with the wheel by the piston movement of the wheel cylinder 50. The drum 10 is instantaneously moved, and at this time, the lining 40 attached to the outer surface of the brake shoe 30 is compressed to the brake drum 10 to rotate the brake drum 10 by using friction force. By stopping it, you can brake.

Here, the lining 40 is directly compressed to the brake drum 10 that is rotated during the operation of the brake to generate a strong friction force, wherein the temperature of the brake drum 10 at a high temperature of about 200 ~ 300 ℃ As it rises, there is a disadvantage in that a phenomenon occurs due to heat deformation.

The conventional brake drum material mainly applied to commercial vehicle trucks is FC250, which has a tensile strength of 25 to 27 kg / mm2. Looking at the content of the constituents, iron is the main component, and carbon ( C) 3.1 to 3.5% by weight, silicon (Si) 1.8 to 2.3% by weight, manganese (Mn) 0.6 to 0.9% by weight, phosphorus (P) 0.1% by weight or less, sulfur (S) 0.1% by weight or less.

The manufacturing process of the brake drum using the conventional brake drum material as described above includes the steps of providing a casting mold; Injecting molten metal in which a brake drum material is dissolved at 1500 to 1550 ° C. into a casting mold, while maintaining an injection temperature in a range of 1450 to 1380 ° C .; Inoculating with Fe-Si inoculum; Cooling to 300 ° C. or lower after casting and demolding; As a post-treatment process, shot blasting and grinding are performed.

However, the conventional brake drum material is produced by the lining is pressed directly to the brake drum is rotated during operation of the brake to generate a strong friction force, the temperature of the brake drum rises to a high temperature, bending or wear due to thermal deformation There is a disadvantage that large occurs.

The present invention has been made in view of the above, it can improve the tensile strength compared to the conventional brake drum to prevent deformation, carbon (C) which is the main component of the brake drum to increase wear resistance to reduce wear , By controlling the content of silicon (Si), manganese (Mn), etc., while adding nickel (Ni), chromium (Cr) and molybdenum (Mo) to increase the tensile strength and improve the wear resistance The purpose is to provide a brake drum.

The present invention for achieving the above object: iron (Fe) as a main component, carbon (C) 3.3-3.7% by weight, silicon (Si) 1.3-2.5% by weight, manganese (Mn) 0.5-1.0% by weight %, 0.1 wt% or less of phosphorus (P), 0.1 wt% or less of sulfur (S), 1.2 to 2.0 wt% of nickel (Ni), 0.3 to 0.6 wt% of chromium (Cr), and 0.3 to 0.5 wt% of molybdenum (Mo) Provided is a vehicle brake drum.

Hereinafter, the present invention will be described in more detail.

The present invention is to provide a brake drum material to improve the tensile strength and wear resistance of the brake drum compared to the conventional brake drum material, the content ratio between the conventional brake drum material and the brake drum material of the present invention is It is as described in Table 1.

As shown in Table 1 above, the brake drum material according to the present invention contains iron (Fe) as a main component, carbon (C) 3.3 ~ 3.7% by weight, silicon (Si) 1.3 ~ 2.5% by weight, manganese ( Mn) 0.5 to 1.0 wt%, phosphorus (P) 0.1 wt% or less, sulfur (S) 0.1 wt% or less, nickel (Ni) 1.2 to 2.0 wt%, chromium (Cr) 0.3 to 0.6 wt%, molybdenum (Mo) When it contains 0.3 to 0.5% by weight, the reason for the content limitation for each component is as follows.

(1) 3.3 to 3.7% by weight of carbon (C)

Carbon is contained for strength improvement, deformation resistance, and thermal crack resistance, and if it is 3.3 wt% or less, there is a possibility of chilling in the thin portion, and deformation resistance and thermal crack resistance may be lowered, and 3.7 wt% or more If the back surface of the coarse graphite crystallization strength may occur.

(2) 1.3 to 2.5% by weight of silicon (Si)

If the content is less than 1.3% by weight, the tendency of the chilling of the matrix structure is increased, so that the deformation resistance is small. If the content is more than 2.5% by weight, the tendency of the chilling process is thickened, so that the content of silicon (Si) is 1.3-. It is preferable to keep it at 2.5% by weight.

(3) 0.5 to 1.0% by weight of manganese (Mn)

The reason for the addition of manganese is to increase the rigidity. If the amount is less than 0.5% by weight, deoxidation and dehydration of the molten metal are insufficient, and if the amount is more than 1.0% by weight, chilling may occur reversely. It is limited to 0.5 to 1.0% by weight.

(4) 0.1 wt% or less of phosphorus (P)

Phosphorus deteriorates formability in the presence of steel and precipitates at grain boundaries, thereby lowering the impact strength. Therefore, phosphorus is preferably controlled as low as possible and preferably limited to 0.1 wt% or less.

(5) 0.1 wt% or less of sulfur (S)

Sulfur (S) is an element that is inevitably contained in the production of steel, and because it is brittle when present in the steel, it is preferable to be managed as low as phosphorus, so it is preferable to limit the content of sulfur to 0.1% by weight or less.

(6) 1.2 to 2.0 wt% of nickel (Ni)

Nickel is preferably limited to 1.2 to 2.0% by weight, and the reason is that if the content is less than 1.2% by weight, the pearlite of the matrix structure is coarsened, and the strength is lowered. Because of this.

(7) chromium (Cr) 0.3-0.6 wt%

It is preferable to limit the chromium to 0.3 to 0.6% by weight, because the reinforcing effect is less at 0.3% by weight or less, and carbide formation is increased at 0.6% by weight or more.

(8) Molybdenum (Mo) 0.3-0.5 wt%

Molybdenum is preferably limited to 0.3 to 0.5% by weight, since the reinforcing effect is less at 0.3% by weight or less, and 0.5% by weight or more inhibits graphitization and increases carbide formation.

Hereinafter, the embodiment of the present invention will be described in more detail with a comparative example, but the present invention is not limited by the following examples.

Example

Iron (Fe) as a main component, carbon (C) 3.54% by weight, silicon (Si) 1.37% by weight, manganese (Mn) 0.56% by weight, phosphorus (P) 0.058%, sulfur (S) 0.037% by weight Casting mold while inoculating the molten metal with Fe-Si inoculum according to the conventional method as described above for a material containing 1.7 wt% of nickel (Ni), 0.6 wt% of chromium (Cr), and 0.33 wt% of molybdenum (Mo). After injection, it cooled to 300 degrees C or less after casting, demoulded, and performed shot blasting and grinding as a post-processing process, and manufactured the brake drum.

Comparative example

Iron (Fe) as a main component, carbon (C) 3.22% by weight, silicon (Si) 2.17% by weight, manganese (Mn) 0.82% by weight, phosphorus (P) 0.049% by weight, sulfur (S) 0.03% by weight Using the current brake drum material (FC250) containing the brake drum was prepared in a conventional manner as in the embodiment.

Component comparison of the brake drum material according to the Example and Comparative Example is as described in Table 2 below.

Test Example

Abrasion test and tensile strength test was carried out for the brake drums prepared according to the Examples and Comparative Examples, the equipment used for the wear test Ogoshi (OGOSHI) wear tester having the specifications shown in Table 3 below (Fig. The equipment used for the tensile strength test used a conventional tensile strength meter, the wear test results are as shown in the accompanying Figure 1, the tensile test results are shown in Table 4 below. As described.

As shown in Table 4 above, the tensile strength of the brake drum according to the present invention was 37.2kg / mm 2, which was 1.4 times higher than the existing tensile strength of 27kg / mm 2 of the brake drum. As can be seen from the average wear amount of the brake drum according to the present invention is 0.013g, it was found that the wear resistance can be improved by 2.4 times lower than the average wear amount of the conventional brake drum 0.031g.

As described above, according to the vehicle brake drum according to the present invention, the content of carbon (C), silicon (Si), manganese (Mn), etc., which are the main components of the brake drum, while controlling the content of nickel (Ni), chromium (Cr) ), By adding molybdenum (Mo), it is possible to prevent deformation by improving the tensile strength compared to the conventional brake drum material, and provides an effect of reducing wear by increasing the wear resistance.

Claims (1)

In a vehicle brake drum, Iron (Fe) as the main component, carbon (C) 3.3-3.7% by weight, silicon (Si) 1.3-2.5% by weight, manganese (Mn) 0.5-1.0% by weight, phosphorus (P) 0.1% by weight or less, A vehicle brake drum comprising 0.1 wt% or less of sulfur (S), 1.2 to 2.0 wt% of nickel (Ni), 0.3 to 0.6 wt% of chromium (Cr), and 0.3 to 0.5 wt% of molybdenum (Mo).

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