JPH01120445A - Rotor for disc brake - Google Patents

Abstract

PURPOSE:To improve high temperature or thermal fatigue strength, mu stability and squalling resistance by impregnating a cavity in a preform disc brake rotor formed of porous graphite having three-dimensional mesh with spherical graphite cast iron and/or cast steel. CONSTITUTION:Porous body having three-dimensional mesh and formed of about 10vol.% of graphite is shaped into a sliding section as a disc brake rotor, then the form body 4 is contained in a san mold 5 and cast steel molten is poured through a pouring gate 6 at the upper end face of the sand mold 5. At the same time, the interior of the sand mold 5 is depressurized from the lower end face by means of a vacuum device through V process casting so as to manufacture a rotor where cast steel is impregnated in the cavity of the preform body 4. A disc brake rotor manufactured through this method has high temperature strength, high thermal fatigue strength, high mu stability and good squalling performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rotor for a disc brake of an automobile, etc., and particularly has excellent strength and friction characteristics.

[Prior art and problems to be solved by the invention] Conventionally, FC rotors or cast steel rotors have been used as rotors for disc brakes, but as the speeds of automobiles and other vehicles increase, the characteristics required for brakes have also changed. Things are getting tougher and tougher. Therefore, the following points to be improved regarding rotors made of these materials are also cited. In other words, FC rotors have excellent frictional properties, but have low room temperature and high temperature strength, and low thermal fatigue strength.On the other hand, cast steel rotors have high strength and thermal fatigue strength, but have poor frictional properties, poor μ stability, and low rotor strength. It has a disadvantage in that it tends to produce linear marks because it has poor scoring resistance, which represents resistance to the scoring phenomenon in which linear marks are produced by one movement on the surface of a store.

(Means for Solving the Problems) In view of this, the present invention has developed a rotor for disc brakes that has the advantages of each of the above rotors and eliminates the disadvantages as a result of various studies. The present invention is characterized in that spheroidal graphite cast iron and/or cast steel is infiltrated into the pores of a disc brake rotor preform formed of a mesh porous body.

[For production]

The three-dimensional network porous body has a skeleton (1
) are three-dimensionally branched in various directions and bonded to each other, and refer to a porous body (3) containing a large number of communicating pores (2), and are conventionally used in sponges, waste gas filters, and air conditioners. Resin-based products are known that are used in vehicle filters, engine air elements, and the like.

However, in the present invention, the main focus is on improving the characteristics of disc brake rotors, and a three-dimensional mesh porous body is formed of graphite, and spheroidal graphite cast iron or cast steel is infiltrated into the pores. When used in a rotor, graphite's excellent lubricity can be utilized to improve μ stability, wear resistance, and scoring resistance. Furthermore, such a three-dimensional network porous material provides a more uniform distribution of graphite, which greatly contributes to uniform wear of the rotor surface. Furthermore, even if it was attempted to mix graphite into conventional cast steel rotors to improve the friction characteristics, it would have been extremely difficult because cast steel does not originally contain free graphite. This purpose can be easily achieved by soaking.

On the other hand, when solid graphite cast iron is infiltrated into this porous body, in addition to the frictional performance of the original spheroidal graphite, the frictional performance of the graphite equivalent to flakes of graphite is added to the frictional performance of the graphite porous body, further improving the frictional characteristics. can be achieved. The size of the mesh and the thickness of the skeleton are not particularly limited, but should be adjusted according to the application of the rotor! It should be determined so as to secure the dormancy coefficient, and when expressed in volume % of graphite, 5 to 10 vol% is appropriate.

In addition, by infiltrating spheroidal graphite cast iron or cast steel into a porous graphite body, it is possible to improve the low strength of conventional FC rotors and obtain a high strength rotor, but this infiltration treatment is performed at high temperatures. Must be implemented. Therefore, the skeleton of the three-dimensional network porous body made of graphite must be caulked to prevent oxidation, and in order to make it easier for molten metal such as cast steel to enter the pores in the porous body, the graphite skeleton of the porous body must be treated with N1. It is an effective treatment to improve wettability with molten metal by plating. Further, as the infiltration method, a vacuum casting method generally referred to as V process casting is preferable.

〔Example〕

Next, the present invention will be explained in detail.

A three-dimensional mesh porous body made of 10 VO1% graphite as shown in Fig. 1 is made into the shape of a sliding product for a disc brake rotor, and this preform body (4) is molded into a sand mold (5
), pouring molten steel from the sprue (6) on the upper end of the core sand mold (5), and simultaneously reducing the pressure inside the sand mold (5) from the lower end using a vacuum device (not shown). We fabricated a rotor with cast steel infiltrated into the pores of the preform body (4), and investigated its frictional properties and strength, which were both excellent, surpassing the advantages of conventional FC rotors and cast steel rotors. I was able to draw it as well.

〔Effect of the invention〕

As described above, the disc brake rotor according to the present invention has excellent properties such as high high temperature strength and thermal fatigue strength, high μ stability, and good scoring resistance.

[Brief explanation of the drawing]

FIG. 1 is an external view showing a three-dimensional mesh porous body, and FIG. 2 is a side sectional view showing an example of the method for manufacturing a disc brake rotor according to the present invention. 1...Skeleton 2...Vacancies 3...Porous body 4...Preform body 5... ... Sand mold 6 ...... Sprue

Claims (1)

[Claims] A rotor for a disc brake, characterized in that spheroidal graphite cast iron and/or cast steel is infiltrated into the pores of a preform body for a disc brake rotor formed of a three-dimensional mesh porous body made of graphite.