disc brake pads

Abstract

A disc brake pad having a friction material having a scorched friction surface provides a disc brake pad capable of preventing fade during the initial use of the disc brake pad while obtaining sufficient braking performance. In a disc brake pad having a friction material having a friction surface that has received thermal history through scorching, the friction surface is mixed with a region with a large thermal history of scorching and a region with a relatively small thermal history of scorching. When the mass loss rate when performing thermogravimetric analysis at 500°C inside the friction material that has not received thermal history of scorching is A, the mass loss rate when performing thermogravimetric analysis at 500°C of the region with the largest thermal history of scorching on the friction surface is B1, and the mass loss rate when performing thermogravimetric analysis at 500°C of the region with a relatively small thermal history of scorching relative to the region with the largest thermal history of scorching on the friction surface is B2, the following equation is satisfied. Formula: 30≤B1 / A×100≤90 50≤B2 / A×100 B2 / A×100-B1 / A×100≤60

Description

Technology Field

[0001] The present invention relates to a disc brake pad used in a disc brake of a vehicle such as a passenger car or a truck, and in particular to a disc brake pad having a friction material having a scorched friction surface. Background Technology

[0002] Conventionally, disc brakes are used as braking devices for automobiles. As a friction member, the disc brake is equipped with a disc brake pad in which a friction material is integrally attached to a back plate.

[0003] The friction material of a disc brake pad is manufactured through a mixing process in which a friction material composition comprising a binder, a fiber substrate, a lubricant, an organic friction modifier, an inorganic friction modifier, a pH modifier, and a filler is mixed to obtain a friction material raw material mixture; a heat-press molding process in which the friction material raw material mixture and a back plate are overlapped and heat-press molded using a thermoforming die; and a heat treatment process in which the curing of the thermosetting resin serving as the binder is completed.

[0004] Disc brake pads are used in combination with a cast iron disc rotor, and braking force is generated by applying the friction material of the disc brake pad to both sides of the rotating disc rotor.

[0005] Generally, continuous use of the brakes leads to a phenomenon known as brake fade, in which braking performance deteriorates.

[0006] This brake fade phenomenon is a deterioration in braking performance caused by the thermal decomposition of organic materials, such as binders or organic friction modifiers, contained in the friction material of a disc brake pad due to exposure to high temperatures and high loads, which generates gaseous or liquid decomposition products; these decomposition products interposed between the friction material and the disc rotor then act as a lubricant.

[0007] It is known that in order to prevent fade in the early stages of use of a friction material, a scorch treatment is performed in the manufacturing process of the friction material by heating the friction surface of the friction material at a high temperature using a hot plate, flame, laser, etc., to burn and remove organic matter that causes the fade phenomenon.

[0008] Patent Document 1 discloses a method for manufacturing a friction material characterized by leaving a portion extending from the outer circumference of the friction material inwardly to a minimum of 1 mm and a maximum of 10 mm, and scorching the other portion, and a method for manufacturing a friction material characterized by scorching the entire surface of the friction material, and then leaving a portion extending from the outer circumference of the friction material inwardly to a minimum of 1 mm and a maximum of 10 mm, and scorching the other portion again.

[0009] According to the manufacturing method of Patent Document 1, by suppressing the decomposition of thermosetting resins, organic reinforcing fibers, etc., in the outer periphery of the friction material, the effect of braking performance during fade can be improved without lowering the friction coefficient and wear resistance performance, but there is a problem that sufficient braking performance of the brake is not obtained in the normal usage range.

[0010] Patent Document 2 discloses a disc brake pad that generates braking force by frictionally contacting a friction material with a disc rotor, wherein at least one side of the friction material with respect to the rotational direction of the disc rotor is scorched.

[0011] According to the disc brake pad of Patent Document 2, the generation of brake noise can be suppressed by causing a change in physical properties, such as a decrease in the coefficient of friction, a decrease in hardness, a decrease in strength, and an increase in hydrophobicity, on at least one side of the two sides of the friction material disc rotor in the direction of rotation, but there is a problem in that the fade phenomenon cannot be effectively prevented because the central part of the friction surface of the friction material is not scorched.

[0012] Meanwhile, cashew dust is used as an organic friction modifier in the friction material of disc brake pads. Cashew dust has the function of exhibiting good and stable braking performance by forming a film on the friction surface of the disc rotor and generating adhesive friction.

[0013] Although the fade phenomenon in the early stages of use of disc brake pads can be effectively suppressed by scorching the friction surface of the friction material and burning off organic matter such as cashew dust that causes the fade phenomenon, if the cashew dust component on the friction surface of the friction material is burned off, a film of cashew dust is not formed on the friction surface of the disc rotor, and there is a problem in that sufficient braking performance cannot be obtained. Prior art literature

[0014] Japanese Patent Publication No. H09-136971 Japanese Patent Publication No. H10-318307 The problem to be solved

[0015] The present invention is intended to solve the above problems and relates to a disc brake pad having a friction material having a scorched friction surface, used in disc brakes of automobiles such as passenger cars or trucks. The objective of the present invention is to provide a disc brake pad that can obtain sufficient braking performance while preventing fade in the early stages of use of the disc brake pad. means of solving the problem

[0016] Conventional scorch treatment involves high-temperature heating to ensure that the thermal history received by the friction surface of the friction material becomes uniform, thereby allowing the scorch treatment layer, from which organic matter is burned and removed, to have a uniform depth from the friction surface.

[0017] In this regard, the invention was completed by discovering that sufficient braking performance can be obtained while preventing fade during the initial use of the disc brake pad by partially differentiating the thermal history received by the friction surface through scorching treatment, thereby mixing the area where organic matter such as cashew dust has been removed within the friction surface with the area where organic matter such as cashew dust remains relatively abundant.

[0018] The present invention relates to a disc brake pad having a friction material having a scorched friction surface, used in disc brakes of automobiles such as passenger cars or trucks, and is based on the following technology.

[0019] (1) A disc brake pad having a friction surface that has received thermal history through scorching, and is characterized by having a mixture of large and relatively small areas of scorching thermal history on the friction surface. The large areas of scorching thermal history are arranged in multiple numbers spaced apart from each other on the friction surface, and the small areas of scorching thermal history can be arranged in each between adjacent areas of scorching thermal history.

[0020] (2) A mass reduction rate when thermogravimetric analysis is performed at 500°C inside the friction material that has not received the thermal history of scorch treatment, B1 mass reduction rate when thermogravimetric analysis is performed at 500°C in the part of the friction surface with the largest thermal history of scorch treatment, and B2 mass reduction rate when thermogravimetric analysis is performed at 500°C in the part of the friction surface with a relatively small thermal history of scorch treatment compared to the part with the largest thermal history of scorch treatment, and the disc brake pad of (1) above satisfies the following Equation 1.

[0021] [Mathematical Formula 1]

[0022]

[0023] (3) The disc brake pad of (2) above, in which the area ratio of the part with the largest heat history of scorching treatment among the friction surfaces of the friction material is 10~90%.

[0024] The disc brake pad of the present invention has a friction surface of the friction material that is scorched, so that some of the organic matter, such as cashew dust present near the friction surface of the friction material, is removed, thereby effectively preventing fade in the initial stage of use of the disc brake pad.

[0025] In addition, the friction material of the disc brake pad of the present invention has a friction surface in which a portion with a large thermal history of scorching treatment and a portion with a relatively small thermal history of scorching treatment relative to the portion with a large thermal history of scorching treatment are mixed.

[0026] While organic matter such as cashew dust is removed from the friction surface of the area with a large heat history of scorch treatment, a relatively large amount of organic matter such as cashew dust remains on the friction surface of the area with a relatively small heat history of scorch treatment.

[0027] Therefore, a film of cashew dust can be formed on the friction surface of the disc rotor, and good and stable braking performance can be obtained through the resulting adhesive friction. Effects of the invention

[0028] According to the present invention, a disc brake pad can be provided that can obtain sufficient braking performance while preventing fade during the initial use of the disc brake pad. Brief explanation of the drawing

[0029] FIG. 1 is an overall perspective view of a disc brake pad according to the present invention. FIG. 2 is a flowchart presenting an example of a method for manufacturing a disc brake pad. FIG. 3 is a cross-sectional view of a disc brake pad in a scorch treatment process using a surface-emitting laser module. FIG. 4 is an explanatory diagram of the planar shape of the scorched treatment layer viewed from the friction surface side of the friction material. FIG. 5 is an enlarged partial cross-sectional view of a disc brake pad after scorching treatment. Specific details for implementing the invention

[0030] A disc brake pad according to the present invention will be described with reference to FIG. 1.

[0031] (1) Disc brake pad

[0032] The disc brake pad (10) is equipped with a metal back plate (11) and a friction material (12) integrally attached to one side of the back plate (11).

[0033] In the present invention, the friction surface of the friction material is configured so that the thermal history received by the scorch treatment is not uniform, and areas with a large thermal history from the scorch treatment and areas with a relatively small thermal history are mixed.

[0034] (2) Scotch treatment

[0035] In the manufacturing process described later, the friction material (12) has a friction surface with a different thermal history in parts and has a part with a large thermal history of the scorch treatment (strong treatment part) (13) and a part with a relatively small thermal history of the scorch treatment (weak treatment part) (14) compared to the part with a large thermal history of the scorch treatment (13).

[0036] In the area (13) of the friction surface with a large thermal history of scorching treatment, organic matter such as cashew dust on the surface of the friction material is lost, whereas in the area (14) of the friction surface with a relatively small thermal history of scorching treatment, organic matter such as cashew dust remains relatively abundant.

[0037] Meanwhile, in the present invention, the “part (14) with a relatively small heat history of scorching treatment” includes cases where the friction surface has not received the heat history of scorching treatment.

[0038] (3) Reason for partially different composition of the thermal history of the scorch treatment on the friction surface of the friction material

[0039] In the present invention, the thermal history of the scorching treatment of the friction surface of the friction material (12) is configured to be partially different rather than uniform.

[0040] The reason for this configuration is to create a difference in the amount of organic matter, such as cashew dust, remaining on the friction surface of the friction material (12), and to utilize this difference in the amount of organic matter, such as cashew dust, to prevent fade during the initial use of the disc brake pad (10) while obtaining sufficient braking performance.

[0041] (3.1) Anti-fade

[0042] The friction surface of the friction material (12) is scorched, so that some of the organic matter, such as cashew dust present near the friction surface, is removed, thereby effectively preventing the fade phenomenon in the initial stage of use of the disc brake pad (10).

[0043] (3.2) Braking performance

[0044] The friction material (12) of the disc brake pad (10) of the present invention has a friction surface having a portion (13) with a large heat history of scorching treatment and a portion (14) with a relatively small heat history of scorching treatment compared to the portion (13) with a large heat history of scorching treatment.

[0045] A relatively large amount of organic matter, such as cashew dust, remains on the friction surface of the part (14) of the scorching treatment heat history, compared to the part (13) of the scorching treatment heat history.

[0046] Therefore, when using the brake, a film of cashew dust can be formed on the friction surface of the disc rotor, and good and stable braking performance can be obtained through the resulting adhesive friction.

[0047] [Method for manufacturing disc brake pads]

[0048] A method for manufacturing a disc brake pad is described with reference to Figures 2 and 3.

[0049] (1) Mixing process

[0050] A friction material composition is prepared by mixing a predetermined amount of friction material raw materials, such as a binder, a fiber substrate, a lubricant, an organic friction modifier, an inorganic friction modifier, a pH modifier, and a filler, and is introduced into a mixer such as a LOEDIGE MIXER or EIRICH MIXER and stirred until uniformly dispersed to obtain a friction material raw material mixture.

[0051] (2) Pre-forming process

[0052] The friction material raw material mixture obtained from the mixing process is fed into a pre-molding mold, and a pre-molded friction material is obtained by pressure molding using a press device.

[0053] Meanwhile, there are also cases where a mixing process is provided to obtain a mixed friction material by kneading the friction material raw material mixture with a pressure kneader before the pre-forming process, or a granulation process is provided to obtain a granulated friction material by granulating the friction material raw material mixture.

[0054] (3) Heated pressure molding process

[0055] A preformed product obtained from a preforming process and a steel back plate that has been pre-cleaned, surface-treated, and coated with adhesive are overlapped and inserted into a thermoforming die, and a press device is used to heat and press mold the product for 1 to 10 minutes under conditions of a temperature of 140 to 200°C, a pressure of 20 to 80 MPa, to obtain a molded product of a friction material.

[0056] Meanwhile, there are also cases where the pre-molding process is omitted, and any one of the friction material raw material mixture, the friction material raw material kneaded material, or the friction material raw material assembly is fed into a thermoforming mold and heat-pressurized molded.

[0057] (4) Grinding process and other processing processes

[0058] A friction surface is formed by grinding the surface of a friction material using a grinding device equipped with a grinding stone.

[0059] If necessary, chamfers or slits are machined on the surface of the friction material.

[0060] (5) Painting process

[0061] Paint is applied to the parts of the disc brake pad's friction material excluding the friction surface by spray painting or electrostatic powder coating. The baking of the paint is performed simultaneously during the subsequent heat treatment process.

[0062] (6) Heat treatment process

[0063] The painted molded product is heated in a heat treatment furnace at 180 to 250°C for 1 to 5 hours to complete the curing reaction of the thermosetting resin included as a binder in the friction material, and at the same time, the paint applied in the painting process is baked.

[0064] (7) Scotch treatment process

[0065] Referring to FIG. 3, the present invention uses a vertical resonator-type surface-emitting laser module (20), which is a type of semiconductor laser, as a heating means for scorching a friction material (12) formed on one side of a back plate (11) (hereinafter referred to as "surface-emitting laser module (20)"). By moving the surface-emitting laser module (20) and the disc brake pad (10) in relative parallel, and irradiating a plurality of lasers with different energy densities onto the friction surface of the friction material (12), a friction surface is formed in which a region (13) with a large thermal history of scorching and a region (14) with a relatively small thermal history of scorching are mixed with the region (13) with a large thermal history of scorching.

[0066] The scorch treatment process is explained in detail below.

[0067] (7.1) Surface-emitting laser module (VCSEL module)

[0068] A surface-emitting laser module (20) is formed by arranging a plurality of vertical cavity surface-emitting laser (VCSEL) elements (21) (hereinafter referred to as "surface-emitting laser elements (21)") on a single plane, and each surface-emitting laser element (21) can have a variable laser energy density.

[0069] Each surface-emitting laser element (21) positioned opposite the surface of the friction material (12) can be pre-set such that its energy density corresponds to the thermal history of the scorch treatment corresponding to the friction surface of the friction material (12), thereby easily forming a friction surface in which a region (13) with a large thermal history of the scorch treatment and a region (14) with a relatively small thermal history of the scorch treatment relative to the region (13) with a large thermal history of the scorch treatment are mixed.

[0070] As for the surface-emitting laser module (20), for example, a vertical resonator type surface-emitting laser module from Philips Photonics manufactured by the method described in Japanese Patent Publication No. 2015-510279 can be used. The surface-emitting laser element (21) is not limited to a vertical resonator type surface-emitting laser.

[0071] (7.2) Energy Density

[0072] The energy density forming the region (13) with a large thermal history of the scorch treatment is 150 to 1100 kW / m², and the energy density forming the region (14) with a relatively small thermal history of the scorch treatment relative to the region (13) with a large thermal history of the scorch treatment is 0 to 300 kW / m².

[0073] (7.3) Survey distance

[0074] When scorching the friction material (12), the distance (irradiation distance) (G) between the irradiation surface of the surface-emitting laser element (21) and the surface of the friction material (12) is 15 to 300 mm, preferably 30 to 200 mm, and more preferably 50 to 100 mm.

[0075] (7.4) Processing time

[0076] The time for scorching the friction material (12) is 0.5 to 60 seconds, preferably 3 to 10 seconds, and more preferably 4 to 8 seconds.

[0077] If the scorching time exceeds 60 seconds, a large amount of organic matter on the surface of the friction material is lost, and the strength is significantly reduced.

[0078] (7.5) Arrangement of surface-emitting lasers

[0079] The arrangement of the surface-emitting laser module (20) on the friction material (12) is not limited to the arrangement horizontally parallel to the disc brake pad (10) as exemplified in FIG. 3; the surface-emitting laser module (20) may be arranged vertically in alignment with the direction of the friction material (12), or a plurality of surface-emitting laser modules (20) may be arranged in an oblique figure-eight shape to surround the friction material (12).

[0080] (7.6) Planar shape of the scorched layer (planar shape)

[0081] By moving either or both of the surface-emitting laser module (20) or the disc brake pad (10) in parallel, a friction surface can be formed in which a region (13) with a large thermal history of scorching treatment and a region (14) with a relatively small thermal history of scorching treatment relative to the region (13) with a large thermal history of scorching treatment are mixed.

[0082] The planar shape formed by the large thermal history of the scorch treatment area (13) when viewing the friction material (12) from the friction surface side is not limited to the stripe shape along the longitudinal direction of the friction material (12) as exemplified in FIG. 1, and may be formed as any one of the stripe shape along the transverse direction of the friction material (12) (Fig. 4(a)), slanted stripe shape (Fig. 4(b)), grid shape (Fig. 4(c)), wave shape (Fig. 4(d)), houndstooth shape (not shown), or a combination of multiple types, as exemplified in FIG. 4.

[0083] In addition, the planar shape of the part (13) with a large heat history of the scorch treatment is not limited to a straight shape and may be curved.

[0084] In addition, the planar shape of the part (13) with a large heat history of the scorch treatment is not limited to a continuous band-shaped surface, but may be formed intermittently like a dashed line or in a dot shape like a teardrop.

[0085] The width dimension or formation spacing of the large heat history area (13) of the scorch treatment can be appropriately selected.

[0086] As described above, in the present invention, by moving the surface-emitting laser module (20) and the disc brake pad (10) relative to each other and irradiating a plurality of lasers with different energy densities onto the friction surface of the friction material (12), a disc brake pad (10) having a friction material (12) with a partially different thermal history of scorch treatment can be easily manufactured.

[0087] [Method for determining the magnitude of thermal history]

[0088] Referring to FIG. 5, a method for determining the thermal history of a friction material (12) that has undergone scorching treatment will be explained.

[0089] In the present invention, thermogravimetric analysis (Thermogravimetric analysis or Thermal gravimetric analysis, TGA) is employed as a method for determining the thermal history of a friction material (12) that has undergone scorch treatment.

[0090] (1) Principle of determining thermal history

[0091] The magnitude of the thermal history of the friction material (12) due to scorching treatment can be determined from the mass reduction rate when thermogravimetric analysis is performed using a surface sample taken from the surface of the friction material (12) that received the thermal history of scorching treatment and an internal sample taken from the interior of the friction material (12) that did not receive the thermal history of scorching treatment.

[0092] (1.1) Method for sampling the surface of friction material

[0093] Two surfaces of the friction material (12), one with a large heat history of scorching treatment (13) and the other with a relatively small heat history of scorching treatment (14) compared to the large heat history of scorching treatment (13), were drilled to a depth of 0.1 mm using a drilling machine with a diameter of 6 mm, and 20 mg of surface samples were taken from each.

[0094] (1.2) Method for collecting samples from the inside of the friction material

[0095] Using a grinder, the surface of the scorched friction material (12) was ground to a depth of 3 mm that had not received the heat history of the scorching treatment.

[0096] After that, the surface of the friction material (12) after grinding was cut to a depth of 0.1 mm with a 6 mm diameter drill using a drilling machine, and 20 mg of internal sample was collected.

[0097] (1.3) Definition of Mass Loss Rate

[0098] In performing thermogravimetric analysis of samples (surface sample, internal sample) taken from the friction material (12), the mass reduction rate of each sample is defined as follows.

[0099]

[0100] The mass reduction rate when thermogravimetric analysis is performed on each sample taken from the friction material (12) is as follows.

[0101] The interior of the friction material (12) that has not undergone the heat history of scorching treatment has the largest mass reduction rate A when thermogravimetric analysis is performed because organic matter such as cashew dust has not been removed.

[0102] The part (13) of the friction surface (12) with the largest thermal history of scorching treatment has the smallest mass reduction rate B1 when the surface thermogravimetric analysis of the friction material (12) is performed because the most organic matter, such as cashew dust, has been removed.

[0103] For the part (13) of the friction surface (12) with the largest heat history of scorching treatment, the part (14) with a relatively small heat history of scorching treatment has a relatively small amount of organic matter such as cashew dust removed, so the mass reduction rate B2 when thermogravimetric analysis of the friction material surface is greater than the mass reduction rate B1 mentioned above.

[0104] Meanwhile, if the portion (14) with a relatively small heat history of scorch treatment does not receive the heat history of scorch treatment, the mass reduction rate B2 when performing surface thermogravimetric analysis of the friction material (12) becomes nearly equal to the internal mass reduction rate A of the friction material (12).

[0105] From the above, the relationship of the mass loss rate when thermogravimetric analysis of the friction material surface at 500°C is A≥B2>B1.

[0106] (1.4) Relationship between mass reduction rates

[0107] The magnitude of the thermal history of the friction material (12) due to scorching treatment is such that the mass reduction rate by thermogravimetric analysis using a surface sample of the friction material (12) and an internal sample of the friction material (12) that has not received the thermal history of scorching treatment satisfies the following equation.

[0108] By satisfying the following equation, sufficient braking performance can be obtained while preventing fade during the initial use of the disc brake pad (10).

[0109] In addition, if the following equation is not satisfied, in addition to not being able to obtain the above effects, problems such as deterioration of wear resistance and deterioration of the flatness of the friction surface occur.

[0110] [Mathematical Formula 2]

[0111]

[0112] (2) Area ratio of the region with the largest thermal history of the scorch treatment

[0113] The present invention satisfies the above Equation 1, and ensures that the area ratio of the part (13) with the largest heat history of the scorch treatment among the friction surfaces of the friction material (12) satisfies the range of 10 to 90%.

[0114] The area ratio of the largest portion (13) of the heat history of the scorch treatment is preferably 30 to 70%, and more preferably 40 to 60%.

[0115] By setting the area ratio of the largest part (13) of the heat history of the scorch treatment to the above range, the fade resistance and braking performance are further improved.

[0116] (3) Thermogravimetric analysis

[0117] Thermogravimetric analysis was performed using a differential thermobalance (Thermo plus EVO TG8120 manufactured by Rigaku Corporation) under the following conditions. The thermogravimetric loss rate was calculated from the weight loss amount from room temperature to 500°C.

[0118]

[0119] Examples

[0120] The present invention will be specifically described below by presenting examples and comparative examples, but the present invention is not limited to the examples.

[0121] 1. Method for manufacturing disc brake pads of Examples 1–26 and Comparative Examples 1–9

[0122] The friction material composition of the composition shown in Table 1 was mixed with a LOEDIGE MIXER for 5 minutes, and pre-molded by applying pressure of 30 MPa for 10 seconds in a molding die.

[0123] This preform was superimposed on a steel back plate that had been pre-cleaned, surface-treated, and coated with an adhesive, and then molded for 10 minutes in a thermoforming mold under conditions of a molding temperature of 150°C and a molding pressure of 40 MPa, followed by electrostatic powder coating, heat treatment (post-curing) combined with paint baking at 200°C for 5 hours, and polishing to form a friction surface.

[0124]

[0125] Next, disc brake pads were manufactured by scorching under the conditions shown in Tables 2 and 3 (Examples 1 to 26, Comparative Examples 1 to 9).

[0126]

[0127]

[0128] 2. Evaluation Criteria

[0129] For the obtained disc brake pads, fade resistance, braking performance, wear resistance, and flatness were evaluated.

[0130] <1> Nephed

[0131] In accordance with JASO C406 "Passenger Cars - Brake Systems - Dynamometer Test Methods," the minimum friction coefficient (μ) in the first fade test was measured. The evaluation criteria are as follows.

[0132]

[0133] <2> Braking performance

[0134] In accordance with JASO C406 (Passenger Cars - Brake Systems - Dynamometer Test Method), the average friction coefficient (μ) in the second effectiveness test was measured. The evaluation criteria are as follows.

[0135]

[0136] <3> Wear resistance

[0137] In accordance with JASO C427 "Automotive Vehicles - Brake Lining and Disc Brake Pad - Dynamometer Wear Test Method," the amount of wear (mm) of the friction material was measured under conditions of an initial braking speed of 50 km / h, a braking deceleration of 0.3 G, an appropriate number of braking cycles, and a brake temperature of 200°C before braking, and converted into the amount of wear per 1,000 braking cycles.

[0138] The evaluation criteria are as follows.

[0139]

[0140] <4> Plan view of the friction surface

[0141] Three support blocks were placed on a surface plate and adjusted in height. The three ends of the back plate were supported by these blocks. Using a dial gauge, the heights of five points with the greatest thermal history of scorch treatment on the friction surface and five points with relatively less thermal history of scorch treatment relative to the greatest points were measured, and the difference between the highest and lowest heights was calculated. The evaluation criteria are as follows.

[0142]

[0143] 3. Evaluation Results

[0144] The evaluation results are shown in Tables 4 and 5.

[0145]

[0146]

[0147] From each of the above tables, it can be seen that the friction material (12) satisfying the conditions of the present invention is good in all evaluation items of fade resistance, braking performance of the brake, wear resistance, and flatness. Industrial applicability

[0148] According to the present invention, a disc brake pad having a friction material having a scorched friction surface can be provided, which prevents fade during the initial use of the disc brake pad while obtaining sufficient wear resistance and braking performance, thus having extremely high practical value. Explanation of the symbols

[0149] 10: Disc brake pads 11: Backplate 12: Friction material 13: The area with the greatest heat history from the scorch treatment 14: Area with a relatively small scorch heat history relative to the area with the largest scorch heat history 20: Surface-emitting laser module 21: Surface-emitting laser device

Claims

Claim 1 A disc brake pad comprising a friction material having a friction surface that has received thermal history through scorching treatment, wherein the friction surface has a mixture of areas with a large scorching thermal history and areas with a relatively small scorching thermal history, wherein the areas with a large scorching thermal history are arranged in multiple numbers spaced apart from each other on the friction surface, and the areas with a small scorching thermal history are each arranged between adjacently spaced areas with a large scorching thermal history, and wherein the following Equation 1 is satisfied when A is the mass loss rate when performing thermogravimetric analysis at 500°C inside the friction material that has not received the scorching thermal history, B1 is the mass loss rate when performing thermogravimetric analysis at 500°C of the area with the largest scorching thermal history on the friction surface, and B2 is the mass loss rate when performing thermogravimetric analysis at 500°C of the friction material surface area with a relatively small scorching thermal history relative to the friction surface area with the largest scorching thermal history. Pad. [Equation 1] 30 ≤ B1 / A×100 ≤ 90, 50 ≤ B2 / A×100, and B2 / A×100 - B1 / A×100 ≤ 60 Claim 2 delete Claim 3 A disc brake pad according to claim 1, characterized in that the area ratio of the region with the largest thermal history of scorch treatment among the friction surfaces of the friction material is 10 to 90%.

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