JPS6297757A - Sliding member and its production - Google Patents

Abstract

PURPOSE:To cast high damping capacity sliding surface parts having good quality to a light weight and high strength by pouring the melt of flake graphite casting structure having high damping capacity to the sliding surface of a casting mold and near the same, then filling the melt of flake graphite casting structure having high strength into the other mold cavity. CONSTITUTION:The molten metal of, for example, about FC10-15 having the flake graphite casting structure of the high damping capacity is poured at about 1,400-1,410 deg.C through a sprue 4 to the sliding surface 2 of the casting mold 1 and near the same in production of a sliding member such as rotor hub for a brake, etc. The molten metal of, for example, FC20 having the high- strength flake graphite casting structure is thereafter poured at about 1,450-1,480 deg.C to fill the other mold cavity 3. Since both molten metals are the flake graphite cast irons, both cast irons are satisfactorily jointed without the generation of abnormality in the adhered part and the rotor hub having the high damping capacity sliding surface is cast to the small thickness, light weight and high strength. The production cost is thereby reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sliding member such as a rotor hub for a brake and a method for manufacturing the same.

[Conventional technology]

Rotor hubs for brakes are required to have smooth sliding surfaces and low wear, vibration, and noise.

In other words, the brake material is required to have good thermal conductivity and wear resistance, as well as high damping ability. Common sense suggests that these properties are contradictory to each other, and it is extremely difficult to satisfy the above properties with the same material.

As a material that can meet the above-mentioned characteristics, high damping capacity cast iron of about FCIO to FC15 having a flaky graphite structure is said to be most preferable.

[Problem that the invention seeks to solve, α]

However, this high-damping cast iron does not have good mechanical properties, and in order to maintain the necessary strength as a brake, the wall thickness must inevitably increase, which is undesirable as it goes against the current trend of weight reduction. It has consequences.

On the other hand, spheroidal graphite cast iron, vermicular cast iron, and even flake graphite cast iron with an FC of 20 or higher are used for brake materials that require strength, but these sacrifice the original brake performance and are not used in the industry. Therefore, it is strongly desired to develop a brake material that combines the braking performance of high-damping flake graphite electric iron with the strength of spheroidal graphite cast iron, vermicular cast iron, and even high-strength flake graphite cast iron with an FC of 20 or higher. This is where I am.

The present inventors have made the sliding surface and its vicinity made of flaky graphite cast iron, which was previously applied for in VR-Application No. 58-115266,
We have developed a sliding member in which other parts have a spheroidal graphite structure and/or a vermi-A gill graphite structure.

However, for spheroidal graphite cast iron or vermicular cast iron, the molten metal treatment such as spheroidization treatment or permicular treatment is complicated, and the joining of spheroidal graphite cast iron or vermicular cast iron and flaky graphite cast iron is difficult. Compared to J) when joining Y4 materials, abnormalities tend to appear at the boundary between J) and initial manufacturing is difficult, and joining with high-damping flake graphite cast iron at the joint requires delicate control such as the timing of casting. It has the disadvantage that it requires

Therefore, the present inventors have developed a new technique that can overcome the drawbacks of the conventional techniques described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sliding member and a method for manufacturing the same, in which desired parts are provided with the characteristics necessary for a sliding member, and other parts are made of a material with excellent mechanical properties.

[Means for solving problems]

The sliding member of the present invention has a flaky graphite structure with high damping capacity on the sliding surface and the vicinity thereof, and has a flaky graphite structure with high strength in other parts, and the manufacturing method thereof is as follows: After injecting molten metal with flaky graphite cast iron composition with high damping capacity into the mold cavity corresponding to the moving surface and its vicinity, other mold cavities are filled with molten metal with high strength flake graphite cast iron composition. It is.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a sectional view of the mold.

<1) Chemical composition A molten metal having a composition of high damping flake graphite cast iron consisting of iron, unavoidable impurities, and the components listed in Table 1 is placed in the mold chamber-gap 2 corresponding to the sliding surface and its vicinity in the mold 1. Injected from sprue 4. The injection temperature at that time was 1,400 to 1,410°C.

fISi table (11t%) Next, a high-strength flaky 21 lead cast iron composition consisting of iron, impurities, and the components shown in Table 2 is injected into the other mold cavity 3 in the mold 1 through the sprue 5. did. The injection temperature at that time was 1,450 to 1.460°C.

Part 2 Table (wt%) (2) Mold A green mold was used as the mold.

(3) Hardness: Prinell hardness of high-damping flake graphite structure: 149. 156 High strength flake graphite structure part 1 Linell hardness 201. 197 (4) Results As is clear from Figure 2, the sliding surface and its vicinity are a high-damping flake graphite structure with a large amount of graphite, which has excellent braking performance, and the other parts are mechanical as shown in Figure ptS3. A high-strength flaky graphite structure containing fine graphite with good mechanical properties was obtained.

Further, in FIG. 4, the boundary between the high-damping-ability flake graphite structure and the high-strength flake graphite structure was not clearly recognized, and it was confirmed that the material had sufficient strength as a sliding member.

In the embodiments described above, a green mold was used, but the present invention is not limited to this, and the same purpose can be achieved by using a metal mold or a pond sand mold.

[Effects of the Invention] As is clear from the above description, the sliding member of the present invention has a high-damping flake graphite structure on the sliding surface and its vicinity, and has a high-strength flake graphite structure in other parts. This material has extremely excellent properties as a rotor hub material for brakes.

In other words, the sliding surface having a flaky graphite structure with high damping ability not only has good thermal conductivity and Ps wear resistance, and has a large damping ability and can satisfy all the characteristics required as a brake material. The other parts have a high-strength flaky graphite structure, so the mechanical properties are extremely good.

Therefore, compared to conventional brake materials, it has many ripple effects such as weight reduction due to reduced wall thickness, noise reduction, fuel efficiency improvement, safety improvement, 9＠ reduction in man-hours, and even lower manufacturing costs. This has extremely excellent industrial effects.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the mold, and Figures 2.3.4 are both micrographs of the metal structure at 50x magnification. 1: Mold, 2.3: Mold cavity, 4, 5: Sprue

Claims (2)

[Claims] (1) A sliding member characterized by having a flake graphite structure with high damping capacity on the sliding surface and its vicinity, and having a flake graphite structure with high strength in other parts. (2) When manufacturing a sliding member in which the sliding surface and its vicinity are made of a flaky graphite structure with high damping capacity, and other parts are made of a flaky graphite structure with high strength, the above-mentioned sliding surface and its vicinity are A molten metal having a composition of flaky graphite cast iron with high damping ability is injected into a mold cavity corresponding to the mold cavity, and then other mold cavities are filled with molten metal having a composition of flaky graphite cast iron with high strength. Manufacturing method for moving parts.