JPH01229126A - disc rotor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a disc rotor, which is a component of a disc brake, and particularly relates to an improvement of a disc rotor with excellent wear resistance.

BACKGROUND OF THE INVENTION A conventional disc brake suppresses the rotation of a rotating body such as a wheel of an automobile, and a disc rotor has a metal disk shape, is attached to the rotating body, and rotates together with the rotating body. During braking, the friction band is pressed against the friction surface of the disc rotor, suppressing the rotation of the rotating body, but repeated braking causes wear.
It is desirable that the disc rotor has excellent wear resistance.

Therefore, in the disc rotor described in Japanese Patent Application Laid-Open No. 62-88829, a sprayed layer with excellent wear resistance is formed on the friction surface. The material for the sprayed layer is Fe-C.
Although an R-based alloy or the like is used, this thermal sprayed layer has 4 to 8% pores due to manufacturing reasons, and the surface of the friction pad is likely to be scraped by the pores generated on the friction surface. Also,
Part of the friction pad that has been scraped off or chipped enters these pores, and organic components such as resin and rubber dust contained in the band components are melted by the frictional heat and organic components are deposited on the surface of the disc cloak. A lubricating film may be formed and the coefficient of friction may decrease.

Therefore, in the invention disclosed in the above-mentioned publication, the pores on the surface of the sprayed layer are impregnated with copper or a copper alloy to fill the pores. In this way, it is possible to avoid a decrease in the coefficient of friction caused by pores on the surface of the sprayed layer.

Problems to be Solved by the Invention However, the disk cloak described in -1- has a problem in that it is difficult to make contact with a friction bat at the initial stage of use. Due to machining dimensional errors and assembly errors of the disc rotor and friction butt, the contact of the friction butt against the disc rotor during braking may become poor, and if it is a conventional disc rotor, braking will be repeated. Over time, the friction surfaces of both the disc rotor and the friction butt wear out, and the contact area between the two increases relatively quickly, resulting in better contact. The friction pad is made up of layers and is hard to wear out, and the pores are filled in so the friction pad is hard to wear out, so the contact area between the disc rotor and the friction pad increases unless braking is repeated many times compared to conventional methods. Therefore, the apparent coefficient of friction does not increase easily.

Against this background, the present invention aims to provide a disc rotor that has excellent wear resistance and can also avoid the lack of a coefficient of friction caused by poor contact with the friction bat in the initial stage of use. It is what was done.

Means for Solving the Problems The gist of the present invention is to provide a disc cloak in which a first coating layer made of a Pa wear-resistant coating material is formed on the friction surface.
The second coating layer, which is softer than the first coating layer, is formed on the first coating layer.

The second coating layer has Hinocurs hardness (hereinafter abbreviated as Hv)
It is preferable that it be made of a metal with a molecular weight of 150 or less.

Functions and Effects In the disc rotor configured as described above, the second coating layer forms the friction surface at the initial stage of use of the disc rotor, so even if the contact with the friction surface of the friction butt is poor, it will be relatively smooth. If braking is performed a few times, the second coating layer will wear out according to the slope and unevenness of the friction surface of the friction butt, or will be transferred onto the surface of the disc rotor, and the second coating layer will also form on the friction surface of the friction pad. The material transfers, the contact area between the disc claw and the friction butt increases rapidly, and the coefficient of friction increases. Since the second coating layer is softer than the first coating layer, the coefficient of friction increases faster than when the friction surface is formed of the first coating layer.

Moreover, the second coating layer will wear out if the braking is performed a certain number of times, but during that time the friction surfaces of the first coating layer and the friction butt become familiar and the contact between the two becomes good, so it remains stable. This results in a high coefficient of friction.

As described above, according to the present invention, it is possible to avoid insufficient braking force at the initial stage of use of a disc rotor having excellent wear resistance.

If a metal having an HV of 150 or less is used as the material of the second coating layer, the effects of the present invention can be particularly effectively enjoyed.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing a disc rotor (hereinafter simply referred to as rotor) 10, which is an embodiment of the present invention. This disc rotor 10 is of the Henchrette sodo type,
The main body 12 is cast from gray cast iron (JIS Fe12). The main body 12 includes a bottomed cylindrical portion 14 and a flange portion 16 extending radially outward from the open end of the cylindrical portion 14 . Bottomed cylindrical part 1
4 is fitted into the host portion of the axle hub through a fitting hole 18 formed at its bottom, and fixed to the flange portion of the axle hub with bolts not disclosed.

The outer diameter of the flange portion 16 is 26011. The thickness (dimension in the rotor rotation center line direction) is 22 mm, and a plurality of ventilation holes 20 extending from the center side of the rotor 10 to the outer circumferential side are spaced equidistantly in the circumferential direction in the central part in the thickness direction. It is formed.

A first coating layer 22 is provided on both surfaces of the flange 16, respectively.
A second covering layer 24 is formed on the first covering layer 22. Therefore, at the beginning of use of the rotor, the surface of the second coating layer 24 forms the friction surface 26,28. First coating layer 22° Composition and Hv of second coating layer 24
is as follows. Note that this composition is expressed in weight percent.

[First coating layer 22] Chromium: 30% Iron: 19% Carbon: 1% Copper: Remaining Hv: 250 [Second coating layer 24] Same as ε ・ ・ ・・ ・ 100%Hv: 113 First coating layer 22. The second coating layer 24 is formed by plasma spraying, and the first coating layer 22 is 0.35
After being formed with a thickness of ***, the second coating layer 24 is formed with a thickness of 0.
The second coating layer was formed to a thickness of 0.05 va and then ground to a thickness of 0.03 l.

In order to confirm the effect of the rotor 10 of this example, braking was performed using a disc brake equipped with this rotor 10, and the coefficient of friction was measured. The disc brake is a pin slide type caliper floating type with a cylinder diameter of 60 mm. The test method was to perform 200 braking operations to decelerate the vehicle from a speed of 65 km/h at a deceleration of 0.35 G under an inertia of 6 kg m s 2 . Note that the temperature of the rotor 10 before braking is 120°C. The change in the coefficient of friction during this test was shown by the solid line in Figure 2.

For comparison, a test similar to that of the rotor 10 of this embodiment was conducted on a rotor in which only the first coating layer 22 was formed on the flange portion 16, and the friction coefficient was as shown by the broken line in FIG. Ta.

As is clear from the results of this test, the rotor of the comparative example had a low coefficient of friction at the beginning of braking, and after 100 braking cycles it gradually became stable and a high coefficient of friction was obtained. In the rotor 10 of this embodiment, a high coefficient of friction can be obtained from the initial stage of braking.

When we observed the friction surfaces of both rotors and friction pads after braking was repeated 200 times, we found that the friction surfaces of the rotor of the comparative example had grinding marks from the rotor manufacturing process, and there were almost no friction marks caused by the friction pads. It was observed that approximately 50% of the friction surface of the friction pad was in contact with the rotor. In contrast, the friction surface of the rotor 10 is about 80% of the second coating layer 24.
was worn out, and friction marks caused by the friction pad were formed concentrically along the circumferential direction of the rotor 10 on the entire friction surface. Further, it was confirmed that about 80% of the friction surface of the friction bat was in contact with the rotor, and a large amount of copper in the second coating layer 24 was transferred.

As is clear from these, the rotor 1 of this embodiment
0, the soft second coating layer 24 wears out in the early stages of braking, and the copper that is its forming material is transferred onto the friction surface of the rotor 10 and further transferred to the friction surface of the friction pad, so that the contact area between the two is reduced. increases rapidly and a high coefficient of friction can be obtained. Then, the second coating layer 2
4 is completely worn away and the first covering layer 2 consists of a wear-resistant material.
2 comes into contact with the friction pad, but at this point the friction surfaces of the second coating N24 and the friction pad have become familiar and the bad contact has been resolved, so a stable high coefficient of friction is maintained thereafter. can get.

The compositions of the first coating layer and the second coating layer are not limited to those mentioned above, for example, [First coating layer] Chromium sesquioxide...50% i. . . . . . . . . . 50
%Hv: 600 [Second coating layer] Aluminum alloy...100% HV: 100 The first coating layer has excellent wear resistance, and the second coating layer is softer than the first coating layer. Preferably Hv15
It is sufficient if it is 0 or less.

Further, the first coating layer and the second coating layer may be formed by means other than thermal spraying.

Furthermore, the present invention can be applied to disc rotors other than the Henchrette sod type.

In addition, various modifications may be made based on the knowledge of those skilled in the art.

The invention can be practiced in modified forms.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a disc rotor which is an embodiment of the present invention. FIG. 2 is a graph showing changes in the friction coefficient of the disc rotor together with changes in the friction coefficient of the comparative example. 10: Disc rotor 12: Main body 22: First coating layer 24 Second coating layer 26.28: Friction surface

Claims (1)

[Claims] In a disc rotor in which a first coating layer made of a wear-resistant material is formed on the friction surface, a second coating layer that is softer than the first coating layer is formed on the first coating layer. A disc rotor characterized by: