JPH0742563B2 - Aluminum alloy disc brake rotor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a disc brake rotor for vehicles, particularly for automobiles.

Conventional technology At present, disc brake rotors for disc brakes generally have good wear resistance and heat resistance, so cast iron made from FC20 to FC30 standards is required, and further wear resistance and heat resistance are required. In this case, a cast product made of a material obtained by adding a required amount of one or more components such as chromium, molybdenum, nickel, copper and silicon to the above cast iron component is used. Further, in addition to the usual shape, for the purpose of improving the cooling property, for example, the actual construction of Shokai 57-13974 is used.
A ventilation type is also used, as described in the publication.

Problems to be solved by the invention As described above, the alloy element added is expensive, and the ventilation type has a complicated structure, and at the time of casting, requires a high-cost core, etc. None of them are advantageous in terms of price, there are various problems in terms of manufacturing control, and there is a problem that all of them, including those made of cast iron, are heavy.

As a result of various studies in view of the above points, the present invention forms a rotor base from an aluminum alloy that is lightweight and has good thermal conductivity, and forms a plasma on the friction surface with the pad. The inventors have found that a rotor having a wear-resistant alloy sprayed layer formed by a jet spraying method can solve the above-mentioned problems, and completed the present invention. In the present specification, the composite fine particles refer to a mixture of plural kinds of fine particles having different components from each other. The main point is that the disc brake rotor is made of an aluminum alloy, and the friction surface of the rotor with the pad of the rotor is made of composite fine particles containing aluminum, iron, chromium, or nickel or alloy fine particles of the same component. The first sprayed layer is formed by spraying by the spraying method, and then the fine particles of the cast iron-based component or the alloy fine particles of the same component are sprayed on the first sprayed layer by the plasma jet spraying method. An aluminum alloy disc brake rotor is characterized in that a thermal sprayed layer is formed on the aluminum alloy disc brake rotor.

Although the rotor is formed as described above, as the aluminum alloy for forming the rotor, that is, the rotor matrix by casting, an appropriate alloy may be selected from the standards JISH 5202, JISH 5302, etc. Things have a specific gravity of 2.
The rotor has a specific gravity of 7.0 to 7.8, which is about 7 to 3.0. The weight of the rotor according to the invention is about 40%, and the weight can be reduced by about 60% as compared with the conventional rotor.

The alloy layer of the component having good wear resistance is spray-formed by the method of plasma jet on the friction surface of the pad of the rotor base, but if it is directly formed, thermal expansion is caused by the large difference in the component. Since the coefficients are different, peeling and deformation are likely to occur, and a sufficient adhesion force between the rotor base and the alloy layer formed by thermal spraying cannot be obtained, and the function as a wear resistant layer cannot be exhibited.

Therefore, during plasma jet spraying, the high temperature of the plasma gas causes an exothermic reaction to form an intermetallic compound, which can cause a metallurgical bond between the sprayed layer and the base aluminum alloy surface. Moreover, heat-generating type composite fine particles containing alloy components forming the second layer and common components, that is, aluminum, iron, chromium, and nickel, or alloy fine particles containing the same components, are used as the rotor friction surface. Is sprayed by the method of plasma jet spraying on the aluminum alloy surface to form a first sprayed layer.
By using heat-generating type fine particles like this,
A metallurgical bond is formed with the rotor base made of an aluminum alloy to prevent the base from breaking and delamination from the base.

Generally, in the case of thermal spraying with a plasma jet, the temperature of the thermal spraying material falls between the thermal spraying nozzle and the mother body, and it is difficult to form a metallurgical bond with the thermal spraying material itself. By using the above-mentioned heat-generating type fine particles as the thermal spray material, the thermal spray reaction of the plasma gas due to the high temperature of the plasma gas melts and a metallurgical bond can be formed between the thermal spray material itself and the base material.

In the above case, the thickness of the sprayed layer formed cannot be unconditionally determined in relation to the roughness of the surface of the rotor matrix, but for example, if the surface is 3
If the finish is μ, it is necessary to be at least double that of 6 μ or more.

Next, the second sprayed layer is formed on the first sprayed layer. Since the second sprayed layer forms a friction surface with the pad, the fine particles used as the spraying material are generally rotors. The fine particles made of a cast iron-based component having wear resistance and the alloy fine particles having the same component are used. These fine particles can form a sprayed layer excellent in the prevention of seizure of the pad and the rotor and the stability of the surface.

In the above case, the bonding between the second sprayed layer and the first sprayed layer is mechanical, and the first sprayed layer and the second sprayed layer are formed as a mixed structure, but Since the thermal spray layer is formed of a material having a high hardness and a component common to that of the second thermal spray layer, the bond is strong and the second thermal spray layer does not peel off when used as a rotor. Not at all.
Further, the thickness of the second sprayed layer is preferably about 0.5 mm to 0.7 mm. If it is thinner than this, it cannot be said that it is desirable from the life of the rotor, and it may be 0.7 mm or more, but from the viewpoint of cost. Not preferred.

EXAMPLES The present invention will be described in detail below based on examples shown in the drawings.

Example A rotor was formed by casting using an aluminum alloy (JISH 5302-ASTM-S12A). The friction surface with the pad, that is, the sprayed surface, is used to enhance the anchoring effect and the fusion effect of the sprayed material.
After finishing with μ, water, oil, oxide film and other dirt were removed and cleaned.

Then, as composite fine particles forming the first sprayed layer, aluminum 55.5 wt% iron 25.0〃 nickel 5.0〃 chromium 7.0〃 residual binder was sprayed by plasma jet.

As the jet equipment, Metco 9MB type manufactured by Metco was used.

Spraying conditions Working gas Mixed gas of argon and hydrogen Working current 600Amp Spraying distance 70mm Nozzle outlet temperature 10.000 ° C The first sprayed layer having a thickness of 0.2mm was formed as described above. In this case, the temperature of the rotor was about 150 ° C., but since the components of the composite fine particles, such as iron and aluminum, are of the exothermic type, that is, iron and aluminum melt and react at high plasma temperatures, and Fe ₃ Al or FeAl Were generated, and due to the heat of formation, they were fused to each other on the sprayed surface to form a strong metallurgical bond.

Then, under the same operating conditions as described above, composite fine particles of 3.5% by weight of carbon, 0.35 〃 iron and 96.15 〃 of carbon were sprayed onto the first sprayed layer to form a second layer having a thickness of 0.6 mm. The bonding between this layer and the first layer is mechanical unlike the above-mentioned bonding between the rotor and the first layer, but the degree of bonding is strong, and there is no peeling at all. .

As described above, the rotor base is formed of an aluminum alloy which is lightweight and has good heat conductivity, and the intermediate layer (first layer) is interposed on the friction surface by the plasma spraying method, which is the same as the conventional one. Was able to form a layer with better abrasion resistance.

The composite fine particles according to the present invention are used by evaporating each of the required metals or elements into the high temperature of the plasma jet to obtain fine particles by rapid cooling and condensation, and mixing the fine particles in the mixing ratio. It goes without saying that the same results are obtained even if the fine alloy particles produced in the same manner as above are used.

Comparative Test Next, the results of the comparative test of the temperature increase due to the number of times of braking of the rotor manufactured according to the above-described embodiment and the conventional rotor having the same structure as that of the rotor will be described together with the temperature increase of the corresponding pad with reference to the drawing of the graph. All tests were automated based on JASO standards.

Fig. 1 shows the temperature when the braking interval is 40 seconds and the number of braking is 10 times. Fig. 2 shows the temperature when the interval is 40 seconds and the number of braking is 15 times. Fig. 3 shows the temperature when the braking interval is 20 seconds and the number of braking is 40 times. Show rise.

In each figure, the curve indicated by the reference numeral 1 is a temperature rise of the rotor according to the present invention, the similar curve indicated by the reference numeral 1'is a curve showing the temperature rise of the pad corresponding to the above, and the reference numeral 2 is a solid line. The curve shows the temperature rise of the conventional cast iron rotor, and the similar curve shown by the reference numeral 2'is the curve showing the temperature rise of the corresponding pad.

As is clear from each figure, the rotor according to the present invention has a good heat dissipation, so that the temperature rise is remarkably slower than that of the conventional one, and the temperature can be kept as low as about 150 ° C. at the final stage. it can.

Effects of the Invention As described above, a rotor base is formed of an aluminum alloy which is lightweight and has good thermal conductivity, and an aluminum alloy and a friction material and an alloy layer having a good bonding property are formed on the rotor base by a plasma jet spraying method. By developing a rotor with a friction layer, it is possible to significantly reduce the surface temperature of the rotor as compared with the conventional cast iron rotor, and therefore, the life of the rotor is extremely extended and the wear of pads is also reduced. Significantly reduced and longer life can be achieved. Needless to say, the weight of the rotor has been significantly reduced (about 60%), which contributes to the weight reduction of the automobile. However, the unsprung weight of the rotor is lightened, and the stability and riding comfort of the steering wheel are improved. Improved. Furthermore, in terms of manufacturing from casting to products, the process control becomes easy, and the manufacturing cost can be reduced. Furthermore, there is no fear of troubles due to the occurrence of heat cracks peculiar to cast iron castings.

[Brief description of drawings]

FIGS. 1, 2, and 3 show the results of a comparative test of temperature rise with the number of times of braking of the rotor according to the present invention and the conventional rotor. FIG. If the number of braking times is 10 times per second, and Fig. 2 is the same for 40 seconds and 15 times,
FIG. 3 is a diagram showing a case where the interval is 20 seconds and the number of times is 40 times. DESCRIPTION OF SYMBOLS 1 ... Temperature rise curve of rotor according to the present invention 2 ... Temperature rise curve of conventional rotor

Claims (2)

[Claims] 1. A disc brake rotor is formed of an aluminum alloy, and a composite particle containing aluminum, iron, chromium, and nickel or an alloy particle containing the same component is plasma jet sprayed on a friction surface with a pad of the rotor. To form a first sprayed layer, and then fine particles of a cast iron-based component or alloy fine particles of the same component are sprayed on the first sprayed layer by a plasma jet spraying method. An aluminum alloy disc brake rotor characterized in that two sprayed layers are formed. 2. The aluminum alloy disc brake rotor according to claim 1, wherein the composite fine particles are a mixture of fine particles of aluminum, iron, chrome and nickel.