JPH1030666A - Brake pad excellent in heat insulating performance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance heat insulating performance by forming plural cavity parts in a liner and/or a friction plate in the vicinity of a fixing boundary part containing a plating layer. SOLUTION: A molding is obtained by performing compression molding on a mixture of Cu, Sn, Ni, SiO2 , mica and graphite. A molding to make a friction plate is obtained by molding a groove to become a cavity part having a width of 3mm and a depth of 3mm on one surface of this molding so as to become an interval of 5mm. This molding is placed on a liner composed of a hot rolling steel plate (SAPH 440) for an automobile structure on which Cu plating having a layer thickness of 5μm is performed, and is sintered in a hydrogen atmosphere, and a brake pad is obtained. Due to such a structure, heat insulating performance is improved, and heat generated particularly at frictionally actuated time is cut off, and a restraining effect of a brake squeal is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

The present invention relates to a brake pad excellent in heat insulation, and more particularly to a brake pad excellent in heat insulation which insulates heat generated at the time of frictional operation and has a high brake noise suppression effect.

[0002]

2. Description of the Related Art A brake pad composed of a back plate and a friction plate has two types: a friction plate formed of an organic friction material in which a filler is bonded by a matrix of an organic substance such as resin or rubber; -Is formed of a metal-based sintered friction material which is bonded with a matrix of a metal, an alloy or an intermetallic compound.

[0003] Of these conventional brake pads, in the case of a friction plate made of a metal-based sintered friction material, frictional heat generated during braking is transmitted to the entire brake system,
There is a problem of deteriorating the caliber and brake oil. Further, when the frictional heat is further increased, the brake oil boils and becomes bubbles, causing a phenomenon of paper lock, which causes a state in which the brake cannot be operated.

A number of proposals have been made to solve these problems.
There are JP-A-7-154536, JP-A-62-37530 and JP-A-62-209235.

[0005]

Japanese Patent Laying-Open No. 57-154536, which is a prior art relating to a brake pad, discloses that a groove is formed on a surface of a back plate to be bonded to a lining.
There is disclosed a friction pad configured so that a groove is filled and buried by running by molding of a lining and a back plate. The friction pad disclosed in the publication also has a number of through holes formed in the back plate, and improves the adhesive strength and shear strength between the lining pad and the back plate in the same manner as the one in which the lining material of this through hole is embedded. However, there is a problem that the frictional heat generated during operation easily causes the boiling of the brake oil and the paper lock phenomenon, resulting in an increase in squealing.

Japanese Patent Application Laid-Open No. 62-37530 discloses that a lining pad is welded to a back plate, a groove is formed in a welding surface of the lining pad, and a groove is formed from a sliding contact surface between the groove and the lining pad. Discloses a friction pad in which a slit formed in communication with the friction pad is communicated. The friction pad disclosed in the publication has a large number of divided lining pads, so that the residual stress is greatly reduced and the heat resistance is improved, but consideration is given to heat insulation. Therefore, there is a problem that the frictional heat generated during operation easily causes the boiling of the brake oil and the paper lock phenomenon, and as a result, the occurrence of squeal increases.

Further, Japanese Patent Application Laid-Open No. Sho 62-209235 discloses the production of a disc brake pad in which a concave groove is formed on a disk sliding contact surface by a ridge having a height of several mm or less formed in a press die. A method is disclosed. In the brake pad obtained by the manufacturing method disclosed in the publication, the effect of preventing the fade phenomenon is enhanced by the concave groove formed in the sliding contact surface, but no consideration is given to heat insulation. For this reason, there is a problem that the friction heat generated during operation easily causes the boiling of the brake oil and the paper lock phenomenon, and as a result, the occurrence of squeal increases.

The present invention has solved the above-mentioned problems. Specifically, the present invention has an excellent heat insulating property in which a plurality of hollow portions for enhancing the heat insulating effect are formed near the fixed boundary between the back plate and the friction plate. The purpose of this is to provide a brake pad.

[0009]

SUMMARY OF THE INVENTION The inventor of the present invention has proposed an improvement in a brake pad, in which the friction coefficient does not decrease or fluctuate even under a high-load use condition where the material temperature reaches about 500 ° C., and the wear resistance is improved. For many years, the requirements of higher insulation and higher productivity without lowering the noise and lowering the squeal during frictional operation have been studied over the years. Based on the premise of a brake pad structure that does not lower it, paying special attention to heat insulation, it is possible to enhance the reduction of squeal by the air cooling effect of the cavity, and the stable friction characteristics of the brake pad (particularly at high temperatures) It has been found that the present invention is able to maintain the frictional characteristics, and the present invention has been completed.

That is, a brake pad according to the present invention is a brake pad in which a back plate and a friction plate are fixed with a plating layer made of metal or alloy interposed therebetween. A plurality of cavities are formed in the back plate and / or the friction plate in the vicinity.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The back plate of the brake pad of the present invention has no problem as long as it can retain the strength as a brake pad, and has the same heat resistance and strength as the conventionally used back plate. Materials, specifically, for example, heat-resistant steel represented by cast iron, carbon steel, alloy steel, steel for machine structural use, and stainless steel.

The friction plate fixed to the back plate is not problematic as long as it is a material having friction characteristics as a brake pad, and is a conventionally known and used sintered friction material having excellent heat conductivity. Is preferable, for example, in the case of a sintered friction material having a thermal conductivity higher than 1 W / (m.K), particularly in the case of a metal-based sintered friction material having a thermal conductivity higher than 3 W / (m.K). The effect is high and preferable. Further, when judged from the material of the friction plate, specifically, for example, at least 30% by volume of one or more of metals of Fe, Co, Ni, and Cu and alloys containing these metals are contained. This is particularly preferable because the effect is enhanced in the case of a metal-based sintered friction material containing the following filler.

When the metal-based sintered friction material is used for a friction plate, fillers to be contained in the metal-based sintered friction material include oxides, carbides and nitrides of metals (including semimetals of Si and B). , Fluorides, sulfides, silicides and their mutual solid solutions, carbonates of metals, mineral substances, intermetallic compounds, graphite, carbon, short fibers and at least one of inorganic fibers, specifically, For example, barium sulfate, talc, diatomaceous earth, serpentine, coke, MgO, Fe ₂ O ₃ ,
Friction modifiers represented by TiO ₂ and B ₂ O ₃ , SiO ₂ and A
1N, Al ₂ O ₃ , Si ₃ N ₄ , SiC, B ₄ C, mullite, carbides, nitrides, oxides, silicides of metals belonging to groups 4a, 5a and 6a of the periodic table and their mutual solid solutions. Ceramics, NiSi ₂ , TiSi ₂ , TiAl
_{3, NiAl 3, CuAl 2,} Ni 3 Al, Co 3 Al, Z
intermetallic compounds represented by r ₃ Al, Fe ₃ Al, FeAl ₃ , graphite, MoS ₂ , WS ₂ , BaF ₂ , CaF ₂ , hB
Examples are solid lubricants represented by N, PbO and fluorinated graphite, pulp fibers, rayon fibers, carbon fibers, silica-alumina fibers, potassium titanate fibers, silicon carbide fibers, and boron fibers. It is made of at least one selected from reinforcing materials represented by various fibers or various whiskers.

The plating layer interposed between the back plate and the friction plate is not particularly limited in material and layer thickness as long as it is a material to which the back plate and the friction plate are strongly fixed. Specifically, for example, Ni, Co, C
u, Ni—P, Cu—Zn, and Cu—Sn. The layer thickness is preferably 20 μm or less, and particularly preferably 1 to 10 μm from the viewpoint of the process time and the fixing strength. .

The hollow portion formed at the fixed boundary portion between the back plate and the friction plate has a high effect of air-cooling the heat from the friction sliding surface of the friction plate as a formed position and shape. Any position and shape that does not cause a decrease in the fixing strength between the back plate and the friction plate may be used. Specifically, for example, the shape is, for example, a cross section perpendicular to the fixing surface between the back plate and the friction plate. The shape should be circular, elliptical, semi-circular, semi-elliptical, or polygonal, such as triangular or quadrangular, taking into account the ease of manufacturing, fixing strength, and air cooling effect. It is preferable that one or more types of semicircular, semielliptical or square shapes are arranged in a well-balanced manner. Further, the position where the hollow portion is formed may be located on the back plate side, the friction plate side, or both, and the positions of these hollow portions are uniform considering the fixing strength and the air cooling effect. It is preferable to disperse them in

When observing the shape of these cavities from different directions, the maximum length in the vertical direction to the fixing surface between the friction plate and the back plate (hereinafter referred to as “t”) and the shape on the fixing surface are shown. The relationship with the minimum length (hereinafter, referred to as “h”) is t
≧ h is preferable from the viewpoint of the fixing strength, and the total area of the hollow portion on the fixing surface (hereinafter, referred to as “P”)
It is preferable that the ratio with respect to the total area of the fixing portion on the fixing surface (hereinafter, referred to as “S”) is P: S = 2: 1 to 3:10 from the viewpoint of the fixing strength and the air cooling effect.
It is preferable that the ratio be 1: 1 to 1: 3.

The position and shape of the cavity will be described with reference to the illustrated drawings. First, FIG. 1 is a front view of a friction plate (1) shown from a fixing surface side in which a groove serving as a cavity (3a) is formed in a fixing surface opposite to a frictional action surface. FIG. 2 is a front view of the back plate (2). FIG. 3 shows a state in which a plating layer is formed on the fixing surface on which the groove of FIG.
It is a front view of a brake pad showing the state where it was fixed to back plate (2). FIG. 4 shows the brake pad A shown in FIG.
FIG. 4 is a vertical cross-sectional view with respect to the friction plate surface, which is shown from the -A cross section. 5 to 8 are vertical cross-sectional views similar to FIG. 3 showing a modification of the shape of the cavity (3a). FIG. 9 and FIG. 10 are front views of the back plate from the side of the fixing surface shown as a modification of the shape and position of the cavity (3a) on the fixing surface side of the back plate (2).

The brake pad of the present invention can be manufactured by applying a conventional manufacturing method of a brake pad, but it is preferable to perform the following method from the viewpoint of quality control. That is, in the method for manufacturing a brake pad according to the present invention, a first step of applying metal plating to one surface of a back plate, and a second step of forming a plurality of recesses from the metal plating surface of the back plate to form cavities A third step of placing a molded body obtained by molding the friction composition on the metal plating, and placing the metal-plated back plate and the molded body placed on the metal plating in a non-oxidizing atmosphere. And a fourth step of fixing the back plate and a friction plate obtained by sintering the formed body by heating and sintering.

The brake pad of the present invention is preferably manufactured by the following method in order to simplify and shorten the manufacturing process. That is, the method for manufacturing a brake pad of the present invention includes:
A first step of molding a molded body made of a friction composition having a plurality of recesses for forming a cavity on one surface, metal plating is performed on one surface of a back plate, and the molded body is placed on the metal plating. A second step of placing, the metal-plated back plate and the molded body placed on the metal plating are heated and sintered in a non-oxidizing atmosphere, and the back plate and the molded body are sintered. And a third step of fixing the obtained friction plate.

The non-oxidizing atmosphere in the production method of the present invention specifically represents, for example, vacuum, hydrogen gas, decomposed ammonia gas, nitrogen gas, modified hydrocarbon gas, and inert gas. , Hydrogen gas, cracked ammonia gas, and modified hydrocarbon gas. Further, the temperature for heating and sintering in the production method of the present invention needs to be selected mainly according to the material of the friction plate, and the friction plate is hardened, and may be any temperature at which the friction plate and the back plate are fixed, Specifically, for example, when a friction plate made of a metal-based sintered friction material is used, the temperature is 700 to 1100 ° C.

[0021]

The brake pad of the present invention has a function of air-cooling heat such as frictional heat generated on the frictional action surface of the friction plate when the hollow portion operates, and this air-cooling cuts off or transfers heat to the back plate. The effect of reducing the thermal expansion such as warpage due to the difference in thermal expansion between the friction plate and the back plate increases.As a synergistic effect of these effects, the brake squeal generated during operation from the brake pad is suppressed or damped. This is the function of causing

[0022]

EXAMPLES Using various commercially available starting materials, 2
7% Cu-3% Sn- 10% Ni-15% SiO 2 -5
% Mica-40% graphite (vol%) was weighed and mixed, and the mixture obtained was subjected to pressure molding at a pressure of ² ton / cm ² to obtain a molded body. A groove for forming a hollow part having a width of 3 mm and a depth of 3 mm is formed on one side of the molded body by 5 mm.
Forming was performed so as to form an interval to obtain a formed body for producing the friction plate shown in FIG. The compact was placed on a back plate made of a hot-rolled steel plate for automotive structure (SAPH440) having a thickness of 5 μm and plated with Cu as shown in FIG.
850 in a hydrogen atmosphere with a pressure of 0 kg / cm ²
C. to obtain the brake pad of the product 1 of the present invention shown in FIGS.

Next, in the product 1 of the present invention, no groove was formed on one surface of the molded body, and a groove for forming a hollow portion having a width of 3 mm and a depth of 3 mm was formed on one surface of the back plate by 5 mm.
A brake pad of the product 2 of the present invention shown in FIG.

As a comparative product, of the product 1 of the present invention, the diameter 1
The back plate shown in FIG. 11 in which five 0 mm through holes were formed was used. The through hole was also prepared so that the mixture serving as a friction plate was completely embedded. A brake pad of a comparative product 1 shown in FIG. 12 was obtained in the same manner as the product 1 of the present invention except that molding was not performed.

As a comparative product, of the product 1 of the present invention,
A brake pad of a comparative product 2 was obtained in the same manner as the product 1 of the present invention, except that the groove was not formed on one surface of the molded product.

Further, as a comparative product, of the product 1 of the present invention, as shown in FIG. 13, it was formed into a state in which it was cut from the surface of the formed body to become a friction plate at intervals of 10 mm with grooves of 3 mm width. A brake pad of a comparative product 3 shown in FIG.

The thus obtained products 1 and 2 of the present invention and comparative products 1 to 3 were obtained by using a dynamometer with a moment of inertia of 6.75 kg. m. S ² , friction action area: 50c
m ² , after mating with the partner material: FC25, speed: 50 km / h, surface pressure: 10 kg / cm ² , temperature before braking 100, 150, 200, 250 ° C.
The brake is applied one time at a time, the coefficient of friction at that time, the temperature of the friction plate at a depth of 1 mm from the friction surface on the brake pad side, the temperature of the back plate at a depth of 3 mm from the back of the brake pad, and the temperature of the brake oil in the caliber The measurement was performed, and the results are shown in Table 1.

Next, products 1 and 2 of the present invention and comparative products 1 to 3
Inertia moment: 6.75 kgmsec
^2. Friction action area: 50 cm ² , mating plate: FC25, and after rubbing, speed: 40 km / h, surface pressure:
^{2 to 20} kg / cm ² , temperature before braking: 50 to 200 ° C.
Brake frequency: A friction test was performed under the condition of 100 times, the brake noise at that time was measured by a sound level meter, and it was judged that brake noise occurred when the sound pressure exceeded a certain level, and the brake occurrence rate at that time was calculated. Table 1 shows the results. The thermal conductivity of the friction plates of the products 1 and 2 of the present invention was 3.
5 W / (m.K).

[0029]

[Table 1]

[0030]

According to the brake pad of the present invention having excellent heat insulating properties, the heat generated on the frictional action surface during operation is more likely to be applied to the back plate than the conventional brake pad having no cooling cavity. There is an effect that transmission is suppressed, an increase in oil temperature is also suppressed, and the occurrence rate of squeal is significantly reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a friction plate having grooves for forming a cavity of a product 1 of the present invention in an embodiment.

FIG. 2 is a front view of a back plate of the product 1 of the present invention in the embodiment.

FIG. 3 is a front view showing a state in which a friction plate is fixed on a back plate.

FIG. 4 is a vertical cross-sectional view with respect to the friction plate surface observed along the line AA in the state of FIG. 3;

FIG. 5

FIG. 8 is a vertical cross-sectional view illustrating a modified example of the shape of the cavity observed in the same manner as in FIG. 4;

FIG. 9 and

FIG. 10 is a front view of a back plate exemplified as a modification of a groove for forming a cavity on one side of the back plate.

FIG. 11 is a front view of a back plate in which a through-hole of the comparative product 1 in the embodiment is formed.

12 is a vertical cross-sectional view of a comparative product 1 in which a friction plate is fixed to the back plate of FIG. 11 and observed as in FIG. 4;

FIG. 13 is a front view of a friction plate having a cut groove of the comparative product 3 in the embodiment.

14 is a vertical cross-sectional view of a comparative product 3 in which the friction plate of FIG. 13 is fixed to a back plate and observed in the same manner as in FIG.

[Explanation of symbols]

 Reference Signs List 1 friction plate, 2 back plate, 3a cavity, 3b through hole, 3c cutting groove, 4 plating layer

Claims (12)

[Claims] 1. A brake pad in which a back plate and a friction plate are fixed with a metal or alloy plating layer interposed therebetween, wherein the back plate and / or the friction plate near the fixing boundary including the plating layer. A brake pad having excellent heat insulating properties, wherein a plurality of cavities are formed in a friction plate. 2. The friction plate has a thermal conductivity of 1 W / (m.
2. The brake pad according to claim 1, wherein the brake pad is made of a friction material comprising K) or more. 3. The brake pad according to claim 1, wherein the friction plate is made of a metal-based sintered friction material containing Cu. 4. The device according to claim 1, wherein the cavity is formed near a fixing boundary of the friction plate.
Or the brake pad excellent in heat insulation described in 3. 5. The brake pad having excellent heat insulating properties according to claim 1, wherein said hollow portion is formed near a fixing boundary portion of said back plate. 6. A brake having excellent heat insulating properties according to claim 1, wherein said hollow portion is formed both in the vicinity of a fixed boundary portion between said friction plate and said back plate. pad. 7. The hollow portion has a triangular shape, a quadrangular shape, or a semicircular shape having a minimum area in a cross section perpendicular to a fixing surface of the friction plate and the back plate. A brake pad having excellent heat insulating properties according to any one of claims 1, 2, 3, 4, 5 and 6. 8. The cavity has a maximum length (hereinafter, referred to as “t”) in a direction perpendicular to a fixing surface between the friction plate and the back plate, and a minimum length (hereinafter, referred to as “t”) on the fixing surface.
The brake pad having excellent heat insulating properties according to claim 1, 2, 3, 4, 5, 6, or 7, wherein the relationship with t is represented by t ≧ h. 9. A total area (hereinafter, referred to as a “cavity”) of a cavity formed in a fixing surface between the friction plate and the back plate at the fixing boundary.
"P") and the total area of the fixing portion of the fixing surface (hereinafter, referred to as "P").
P: S = 2: 1 to 3:10
4. The method according to claim 1, wherein:
A brake pad having excellent heat insulating properties according to 6, 7, or 8. 10. The method according to claim 1, wherein said plating layer has a thickness of 20 μm or less.
The brake pad having excellent heat insulating properties described in 8 or 9. 11. A first step of applying metal plating to one surface of the back plate, a second step of forming a plurality of recesses from the metal plating surface of the back plate to form cavities, and friction on the metal plating. A third step of placing a molded body formed from the composition, heating and sintering the metal-plated back plate and the molded body placed on the metal plating in a non-oxidizing atmosphere; A fourth step of fixing a back plate and a friction plate obtained by sintering the formed body to each other, the method comprising the steps of: 12. A first step of forming a molded body made of a friction composition having a plurality of recesses for forming a cavity on one surface, wherein one surface of a back plate is subjected to metal plating, and A second step of placing the compact, heating and sintering the metal-plated back plate and the compact placed on the metal plating in a non-oxidizing atmosphere; And a third step of fixing a molded body to a friction plate obtained by sintering the molded body.