JPH0525607A - Disk rotor - Google Patents

Abstract

PURPOSE:To provide the disk rotor which removes the resin film under formation in the prestage before the degradation of action (coefft. of friction), prevents the degradation in the action (coefft. of friction) and can hold good braking performance at the time of a braking operation under the conditions under which the temps. of the sliding surfaces of the disk rotor and the pressure contact surface of a brake pad rise abnormally high. CONSTITUTION:The thermally sprayed film 3 of the disk rotor 1 having the thermally sprayed film 3 formed by thermal spraying of a thermal spraying material on at least a part of the sliding surfaces 30, 30 is formed of the thermal spraying material consisting of Fe-Cr alloy powder, Cu powder or Cu alloy powder, powder of a hard material and a solid lubricating material. The above- mentioned solid lubricating material 32 is dispersed at 5 to 20wt.% into the thermally sprayed film 3 mentioned above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc rotor incorporated in a disc brake device such as an automobile.

[0002]

2. Description of the Related Art Conventionally, in order to improve wear resistance and corrosion resistance, Fe-Cr, stainless steel, Cu, etc. are sprayed on a sliding surface of a disk rotor which a brake pad of a disk brake device comes into pressure contact with. It is known to form a thermal spray coating. Further, for example, in Japanese Patent Application Laid-Open No. 1-116326, in order to enhance the effect (friction coefficient), which is a basic characteristic of the brake performance, Al ₂ O is contained in the thermal spray coating formed on the sliding surface of the disk rotor. A technique is disclosed in which hard particles such as ₃ are dispersed to generate abrasive friction (irregularities on a contact surface or wear in which a cutting effect of hard particles interposed between friction surfaces is significant).

[0003]

DISCLOSURE OF THE INVENTION A disk rotor having the above-mentioned thermal spray coating formed on its sliding surface is used, for example, when it is incorporated in a disk brake device of an automobile and used.
When the vehicle is operated under a braking condition such as traveling at a normal speed in an urban area (for example, 50 km / h-
In the case of decelerating from the traveling speed at 20 Km / h to 0 Km / h), good braking performance can be obtained. However, in the case where the braking operation is performed under the condition that the vehicle travels at a speed higher than the above traveling speed, or the braking operation is frequently performed under the condition that the vehicle travels down a mountain road or a long slope, the disclosure is performed. The temperature of the sliding surface of the rotor and the pressure contact surface of the brake pad that abuts on the sliding surface become abnormally high (about 250 ° C. or higher). Then, the resin in the pad material forming the break pad melts and adheres to the sliding surface side of the rotating disk rotor from the pressure contact surface, and is formed as a resin film. When the breaking operation is further repeated in this state, the resin coating formed on the sliding surface side of the disc rotor gradually grows to increase its thickness. When the thickness exceeds a certain value, a part of the resin coating is transferred to the pressure contact surface side of the brake pad, and the resin coating is formed on the pressure contact surface.

When the resin film is formed on the sliding surface of the disc rotor and the pressing surface of the brake pad by the molten resin in this manner, either or both of them are formed. -Effective during king operation (friction coefficient)
Deteriorates and there is no problem in practical use, but good break performance cannot be obtained. In order to solve the above problems, the present invention provides the resin coating which is being formed at the time of the breaking operation under the condition that the temperatures of the disc rotor sliding surface and the pressure contact surface of the brake pad become abnormally high. It is an object of the present invention to provide a disc rotor capable of removing the above-mentioned effect in a stage before the effect (friction coefficient) decreases and preventing the effect (friction coefficient) from decreasing and maintaining good braking performance.

[0005]

DISCLOSURE OF THE INVENTION The disc rotor of the present invention is a disc rotor having a sprayed coating formed by spraying a spraying material on at least a part of a sliding surface, wherein the sprayed coating is , Fe-Cr alloy powder, Cu powder or Cu alloy powder, hard material powder, solid lubricant,
And the solid lubricant is dispersed in the thermal spray coating in an amount of 5 to 20 wt%.

The reason why the amount of the solid lubricant dispersed in the thermal spray coating formed by thermal spraying on a part of the sliding surface of the disc rotor is within the range of 5 to 20 wt% is that the temperature is abnormal. When the brake is operated under extremely high conditions, the resin contained in the brake pad melts due to the high temperature and is released.
This is because it can be effectively adhered to the sliding surface of the tape and formed as a peeling material for the resin coating. That is, since the solid lubricant has a layered structure, if it is within the above range, it will fall out of the thermal spray coating together with the resin coating. For this reason,
It is possible to prevent the friction coefficient of the sliding surface from lowering due to the formation of the resin coating on the sliding surface. Further, when the solid lubricant drops off together with the resin coating, a concave portion is formed on the surface of the thermal spray coating, and the resin coating formed on the pressure contact surface of the pad is scraped off at the edge portion of the concave portion. Therefore, practically, the friction coefficient required under the above conditions can be maintained and the wear resistance can be maintained.

Solid lubricant dispersed in the sprayed coating is 5 w
If it is less than t%, the degree of bonding between the solid lubricant and other components contained in the thermal spray coating becomes stronger than necessary, so that the solid lubricant does not easily fall off and is formed on the sliding surface. The effect of removing the resin coating that is being developed is small, and the effect of preventing the reduction of the effect (friction coefficient) and the effect of maintaining good braking performance cannot be obtained.

When the solid lubricant exceeds 20 wt%, the degree of bonding between the solid lubricant and other components contained in the thermal spray coating becomes weak, so that each powder easily falls off and the thermal spray coating is formed. Wear resistance decreases and the amount of wear increases rapidly, making it unusable for practical use. 20 wt% in the thermal spray coating
%, The solid lubricant is continuously present, so when the solid lubricant falls off, the resin coating formed on the pressure contact surface of the pad can be scraped off when the solid lubricant falls off. However, the original lubricating effect of the conventional solid lubricant becomes dominant and the friction coefficient tends to decrease.

Therefore, the dispersion amount of the solid lubricant is 5 to 20 w.
A range of t% is preferred. As the solid lubricant, graphite, mica, molybdenum disulfide (MoS ₂ ), BN or the like can be used.

[0010]

In the disk rotor of the present invention, the sprayed coating formed on the sliding surface has the Fe--Cr alloy powder, the Cu powder or the Cu alloy powder, the hard material powder, and the solid lubricant. Is a layer that is joined in a semi-molten state,
In the layer, the solid lubricant is 5 to 5 in the thickness direction of the thermal spray coating (thickness direction of the disc rotor) and in the plane direction of the thermal spray coating (direction of the circumferential plane area of the sliding surface of the disc rotor). 20w
It exists by being dispersed by t%. Therefore, the solid lubricant can be peeled off when the resin coating being formed on the surface of the thermal spray coating adheres to the solid lubricant. Here, under the condition that the brake operation is frequently performed and the temperatures of the sliding surface of the disc rotor and the pressure contact surface of the pad become abnormally high, the resin component contained in the pad melts and Even in the case where a resin coating film is formed, in the disc rotor of the present invention, the solid lubricating material is present in a dispersed state, so that the resin coating film being formed is a solid lubricating material one after another. At the same time, it is peeled off and removed to the outside. And the part where the solid lubricant is dropped is
It becomes a recess. If a resin coating film is formed on the contact surface side of the pad at this stage, the resin coating film contacts the edge of the concave portion and is scraped off to be removed to the outside. Then, the hard particles are exposed on the contact surface of the pad, and the resin particles remaining on the sliding surface of the disk rotor are scraped off by the hard particles.

[0011]

As a result, the disk rotor of the present invention has the solid lubricant dispersed in the sprayed coating formed in the sliding surface of the disk rotor in an amount of 5 to 20% by weight. The resin film formed on the sliding surface of the pad and the pressure contact surface of the pad can be removed. Therefore, there is no phenomenon of reduction in the friction coefficient due to the formed resin film,
Good braking effect is obtained.

[0012]

EXAMPLE A disk rotor 1 of this example comprises a rotor body 2 and a thermal spray coating 3 as shown in FIG. The rotor body 2 is made of cast iron (JIS FC2
It is made of 0) and is provided with a ring-shaped sliding portion 20 with which the brake pads 4 and 4 come into sliding contact with each other when rotating around the central axis P. Then, the two vertical surfaces of the ring-shaped sliding portion 20 are machined into two machined surfaces 21 and 21.
The sprayed coatings 3 and 3 are formed on the respective surfaces.

Next, the specific contents of the formation of the sprayed coatings 3 and 3 will be described. First, the sprayed coatings 3 and 3 are prepared in advance.
A thermal spray material was prepared to form the. This thermal spray material (90 ^% {50 (Fe-65Cr-3) as a material composed of Fe-Cr alloy + Cu alloy + hard particles having excellent wear resistance
C) +50 (Cu-9Al-1Fe)} + 10 ^% Cr ₃
C ₂ ) and a predetermined amount of graphite added to this material. The amount of graphite added is the same as that of the test sample No. 1 corresponding to Examples 1 to 3 shown below. 1-No. 3 is set. That is, the amount of graphite added was 5 wt in Example 1.
%, 10 wt% in Example 2, 20 wt in Example 3
Plasma spraying was performed on the machined surfaces 21, 21 of the ring-shaped sliding portion 20 of the rotor body 2 under the following spraying conditions using three types of spraying materials. If the size of the graphite particles is too small, the particles sublime during spraying and do not exist in the sprayed coatings 3 and 3. Therefore, the average particle size is preferably about 100 to 200 μm.

Further, the thermal spraying conditions are: current: 500 A, voltage: 70 V, gas flow rate: N ₂ 150 ^{l / min} / H ₂ 20 ^{l / min,} thermal spraying distance: 130 mm.

The discs of the first, second and third embodiments are described below.
As shown in FIG. 2, Fe-Cr alloy powder is formed by spraying the sprayed material on the two processing surfaces 21, 21 on both vertical surfaces of the ring-shaped sliding portion 20 of the rotor 1 as shown in FIG. The sprayed coatings 3 and 3 having a thickness of about 300 μm were formed in which the mixture 31 composed of the Cu alloy powder and the hard material powder and the powder of the graphite 32 in the above addition amount were combined in a semi-molten state. The inside of the thermal spray coatings 3, 3 is in the thickness direction (thickness direction of the disc rotor) and the plane direction of the thermal spray coatings 3, 3 (disc rotor).
Graphite 32 is dispersed and present in the circumferential plane area of the sliding surface of the magnet (see FIG. 2). A typical metallographic photograph of the sprayed coating 3 is shown in FIG. The black portion is graphite 32.

Therefore, the graphite 3 in the thermal spray coatings 3, 3 is
The resin coating 42 is adhered to 2 and can be peeled off when a predetermined external force is applied. Here, in the disc rotor 1 of each of the first, second, and third embodiments, the brake operation is frequently performed, and the pressure contact surfaces 40, 4 of the pad 4 are
Under the condition that the temperature of the sliding surfaces 30, 30 to which 0 is pressed is abnormally high, the resin 41 contained in the pad 4 is melted and the sliding surfaces 30, 30 of the disc rotor 1 are coated with the resin film. Four
In the case where 2 is formed (see FIG. 3), since graphite 32 is dispersedly present in the layer below the resin coating 42 as a material that easily peels off, as soon as the resin coating 42 is formed, The graphite 32 is peeled off one after another (see FIG. 4) and is removed to the outside. Therefore, the growth of the resin coating 40 on the sliding surface 30 is stopped. The removed portion becomes the recess 33 (see FIG. 5). When the resin coating 43 formed on the pressure contact surfaces 40, 40 side of the pad 4 is being formed, the resin coating 43 forms the edge 330 of the recess 33.
It is scraped off by abutting against and is removed to the outside. Therefore, the growth of the resin coating 43 on the pressure contact surfaces 40, 40 of the pad 4 is stopped. . When the resin coating 43 on the pressure contact surfaces 40, 40 of the pad 4 is scraped off, the hard particles 44 are exposed, and the hard particles 44 are slid on the sliding surface 3 of the disc rotor 1.
The resin coating 42 is scraped off by coming into contact with the resin coating 42 remaining on 0 and 30 (see FIG. 6).

Therefore, when the disk rotor 1 of the first, second, or third embodiment is used, the brake operation is frequently performed, and the sliding surfaces 30, 30 and the pressure contact surface of the pad 4 are contacted. Even when the temperatures of 40 and 40 are abnormally high, the sliding surfaces 30 and 30 and the pressure contact surfaces 40 and 4 of the pad 4 are caused by the resin 41 melted from the pad 4 as the temperature rises.
A decrease in the friction coefficient due to the formation of the resin coatings 42 and 43 on the 0 surface is eliminated, and a good braking effect is obtained.

The sliding surface 3 of the disc rotor 1
The thermal spray coatings 3 and 3 formed in the regions 0 and 30 have
The addition of an appropriate amount of graphite 32 within the above range also improves the squealing phenomenon during braking. That is, since the squeal phenomenon occurs due to the resonance between the disc rotor 1 and the pads 4 and 4 during braking, the higher the damping capacity of the disc rotor 1, the more advantageous the squeal is, and the sprayed coating 3,
It is considered that a proper amount of graphite 32 dispersed in 3 enhances the damping ability. (Comparative Example) Next, in order to confirm the effect of the disc rotor 1 of the present embodiment, the test sample Nos. 1, No. 2, No. 3 and Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 test sample Nos. 4, N
o. 5, No. 6, No. 7 was prepared.

Incidentally, the test sample Nos. 4 to No. Reference numeral 7 is a disk rotor having a sprayed coating formed on each of the sliding surfaces 30, 30 by using a sprayed material in which the amount of graphite added is changed in four ways as described below.
That is, the amount of graphite added was 0 in Comparative Example 1, 1 wt% in Comparative Example 2, 30 wt% in Comparative Example 3, and Comparative Example 4
Then, plasma spraying was performed on the machined surfaces 21 and 21 of the ring-shaped sliding portion 20 of the rotor body 2 under the same spraying conditions as in the above-mentioned embodiment, except that the content was 40 wt%. ..

Then, the test sample No. 1 to N
o. 7 was used to perform a test under the following conditions to evaluate the friction coefficient (μ) and wear resistance [wear amount (μm)].
The test conditions are: pad: semi-meta system vehicle speed: 100 kw / h hydraulic pressure: 60 kg / cm ² braking frequency: 100 times.

(Evaluation) As a result of the above-mentioned test, as shown in FIG. 8, the friction coefficient (μ) with respect to the added amount wt% of graphite is 0 w.
t% about 0.23, 1 wt% about 0.27, 5 wt% about 0.37, 10 wt% about 0.4, 20 wt% about 0.39, 30 wt% about 0.3, 40 wt% About 0.
23 (see black circles).

As a result of the above test, as shown in FIG. 8, the wear amount with respect to the addition amount of graphite of wt% is 5 μ at 0 wt%.
m, 6 μm at 1 wt%, 8 μm at 5 wt%, 10 wt%
9 μm, 20 wt% 10 μm, 30 wt% 20 μm
m and 40 wt% changed to 30 μm (see black triangle mark). Then, the test sample Nos. Of Examples 1, 2, and 3 were used.
1, No. 2, No. 3 and the test sample Nos. Of Comparative Examples 1, 2, 3, and 4. 4, No. 5, No. 6, No. As a result of a comparative examination with No. 7, as for the friction coefficient of the sliding surface, a high friction coefficient is secured when 5% or more of graphite is added, as compared with when no graphite is added and when 1% is added. Graphite 1
%, It is presumed that the reason for the low friction number is that the proportion of graphite exposed from the sliding surface is small and the effect of peeling off the resin coating was not exhibited.

On the other hand, the amount of wear (μm) on the sliding surface rapidly increases when the amount of graphite added exceeds 20%. This is presumed to be because a large amount of graphite is present in the thermal spray coating, so that the degree of bonding of the other particles to each other is reduced and the particles are likely to fall off, and the amount of wear on the sliding surface is increased. Therefore, the test sample Nos. Nos. 4 and 5 were not suitable for practical use in the friction coefficient, and the test sample Nos. 6
Indicates that the wear amount is not suitable for practical use, and the test sample No. In No. 7, neither the coefficient of friction nor the amount of wear is suitable for practical use.

On the other hand, the test sample Nos. It was found that Nos. 1, 2, and 3 are suitable for practical use in terms of both the friction coefficient and the wear amount. Therefore, in order to secure the friction coefficient without lowering the wear resistance,
It was confirmed that it is effective to set the addition amount of graphite to 5 to 20%. In this example, graphite was used as the solid lubricant, but even if mica was used instead of graphite, as shown by the white circles in FIG. 7 and the white triangles in FIG.
Almost the same results as when using graphite were obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a part of a disc rotor and a brake pad according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a state in which a resin coating is not formed on the sliding surface of the disc rotor and the pressure contact surface of the brake pad in FIG.

FIG. 3 is a partially enlarged view showing a state in which a resin film is formed on the sliding surface in FIG.

FIG. 4 is a partially enlarged view showing a state where a part of the resin coating film is peeled off from the sliding surface in FIG.

FIG. 5 is a partial enlarged view showing an abutting state of an edge portion of a recess in which graphite is peeled off in a thermal spray coating forming a sliding surface of a disc rotor and a resin coating formed on an abutting surface of a brake pad. Fig.

FIG. 6 is a magnified view showing a state in which the resin coating in FIG. 5 is removed and particles of hard material are exposed on the contact surface and abut on the resin coating left on the thermal spray coating on the sliding surface of the disc rotor to scrape off. Fig.

FIG. 7 is an explanatory diagram showing the addition amounts (wt%) of graphite and mica on the horizontal axis and the friction coefficient (μ) on the vertical axis.

FIG. 8 is an explanatory diagram showing the amounts of graphite and mica added (wt%) on the horizontal axis and the amount of wear (μm) on the vertical axis.

FIG. 9 is a photograph showing an example of the metallographic structure of the sprayed coating at 100 times magnification.

[Explanation of symbols]

1 ... Disc rotor 2 ... Rotor body 3 ... Thermal spray coating
32 ... Graphite 30 ... Sliding surface 4 ... Break pad 40
... Pressure contact surfaces 42, 43 ... Resin coating

Claims (1)

Claim: What is claimed is: 1. A disk rotor having a sprayed coating formed by spraying a spraying material on at least a part of a sliding surface, wherein the sprayed coating is Fe-Cr alloy powder. And a Cu powder or Cu alloy powder, a hard material powder, and a solid lubricant, and the solid lubricant is dispersed in the thermal spray coating in an amount of 5 to 20 wt%. Disc rotor characterized by.