| (11) | EP 3 088 764 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) | FRICTION MATERIAL REIBUNGSMATERIAL MATÉRIAU DE FRICTION |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[Field of the Invention]
[0001] This invention relates to a friction material for a disc brake pad of an automobile or the like, which is manufactured by forming a non-asbestos-organic (NAO) friction material composition.
[Background of Invention]
[0002] Conventionally, a disc brake is used as a brake device of an automobile, and a disc brake pad manufactured by fixing the friction material on a metallic base member is used as a friction member of the disc brake.
[0003] The friction material is classified into three types, i.e., a semi-metallic friction material containing, as a fiber base material, 30 weight % or more but less than 60 weight % of a steel fiber relative to the total amount of the friction material composition, a low steel friction material containing a steel fiber in a part of the fiber base material as well as less than 30 weight % of the steel fiber relative to the total amount of the friction material composition, and the NAO friction material containing no steel-based fiber such as the steel fiber and a stainless steel fiber.
[0004] The friction material causing less braking noise is demanded late years, it is a recent trend to use the disc brake pad that uses the NAO friction material that does not contain the steel fiber and/or the steel-based fiber but mainly contains such as a binder, a fiber base material, a lubricant, a titanate, an inorganic friction modifier, an organic friction modifier, pH adjuster, and a filler.
[0005] For the NAO friction material for the disc brake pad, in order to secure the required performance, about 5-20 weight % of a copper component such as fibers and/or particles of copper and/or copper alloy in total relative to the total amount of the friction material composition, is added as a necessary component.
[0006] However, recently, the above-described friction material, when braking, discharges the copper as abrasion powder, and it is suggested that the discharged copper flows in a river, lake, and/or ocean and then the copper possibly contaminates an area around the discharged copper.
[0007] Because of these background, for example, California State (CA) and Washington State (WA) of the United States of America passed a bill to prohibit the sales of the friction member using the friction material containing 5 weight % or more of the copper component relative to the total amount of the friction material composition and an act of assembling the subject friction material in a new car from the year of 2021, and the sales of the friction member using the friction material containing 0.5 weight % or more of the copper component relative to the total amount of the friction material composition and an act of assembling the subject friction material in a new car several years later from above year of 2021.
[0008] Then, as this type of laws and regulations is expected to be spread out in the world from now on, the elimination of the copper component contained in the NAO friction material is urgently needed, and an issue is to suppress the chipping of an edge of the friction materia! that occurs under the high speed and high load braking conditions.
[0009] The Patent Document 1 discloses the friction material, which is manufactured by forming the friction material composition containing 0.5-50 weight % of the metallic tin or tin alloy relative to the total amount of the friction material composition and 0.001-4.999 weight % of the copper relative to the total amount of the friction material composition
[0010] However, the friction materials disclosed in the Patent Document 1 satisfies the laws and regulations relating to the required amount of the content of the copper component contained therein but cannot be said to solve the problem of a chipping of the edge of the friction material that occurred under the high speed and high load braking conditions.
[0011] The Patent Document 2 discloses the non-asbestos friction material comprising a fiber base, a friction modifier, and a binder, which containing 0.5 - 2.5 volume % of a partial graphitized cokes. The Patent Document 3 discloses the friction material comprising a fiber base, a binder, and a filler, which containing a resilient graphite as the filler and further not containing an organic dust. The Patent Document 4 discloses copper-free NAO friction material compositions containing graphitic components. The Patent Document 5 discloses a NAO friction material comprising a fibrous base material, a friction modifier, a binder, and a partially graphitized coke. These compositions contain up to 4 wt% copper.
[0012] However, neither Patent Document discuss the problem of the chipping of the edge of the friction material that occurred under the high speed and high load braking conditions.
[Prior Arts]
[Patent Documents]
[0013]
Patent Document 1: US Provisional Patent Publication No. 2010/0331447
Patent Document 2: Japanese Provisional Patent Publication No. 2007-326999
Patent Document 3: Japanese Provisional Patent Publication No. 2009-155439
Patent Document 4: WO 2013/054857 A1
Patent Document 5: US 2007/287768 A1
[SUMMARY OF INVENTION]
[PROBLEMS TO BE RESOLVED THE INVENTION]
[0014] An object of this invention is to provide a friction material manufactured by forming a non-asbestos-organic (NAO) friction material composition, which is used for a disc brake pad, in which the friction material is able to suppress chipping of an edge of the friction material that occurs under the high speed and high load braking conditions while satisfying laws and regulations relating to the required amount of the content of the copper component contained therein.
[MEANS TO RESOLVE THE PROBLEMS]
[0015] This invention relates to a friction material utilized for a disc brake pad, which is manufactured by forming the NAO friction material composition as defined in present claim 1. contains in one embodiment of the invention
[0016] The friction material contains in one embodiment of the invention 1-10 weight % of one or any combination of two or more items selected from the group consisting of an aluminum particle, an aluminum fiber, an alloy particle containing aluminum, and an alloy fiber containing aluminum relative to the total amount of the friction material composition as an inorganic friction modifier. 90 % or more of
[ADVANTAGE OF THE INVENTION]
[0017] The present invention, with respect to the friction material utilized for a disc brake pad, which is manufactured by forming the non-asbestos organic friction material composition, can provide the friction material which is able to suppress chipping of an edge of the friction material that occurs under the high speed and high load braking conditions and further to suppress the deterioration of the braking effectiveness under the high speed and high load braking conditions while satisfying laws and regulations relating to the amount of the content of the copper component.
[EMBODIMENT OF THE INVENTION]
[0018] The graphitic carbon particle as defined in present claim 1 has a characteristic of showing a higher recovery ratio of the volume thereof when removing the added compressive load, and such graphitic carbon particle is made by expanding and forming a carbonaceous mesophase or cokes and then graphitizing at 1900 - 2700 centigrade to make the graphitization degree of 80 - 95% according to the X-ray analysis.
[0019] A process of expanding and foaming may be such as (1) a method of acid treating the carbon material with nitric acid or mixed acid of nitric acid and sulfuric acid; dissolving in the alkali aqueous solution; extracting in nitric acid solution to obtain an aqua mesophase; and finally heating the aqua mesophase at about 300 centigrade, (2) a method of heating the carbon material rapidly by contacting the same nitric acid to rapidly heat the same, and (3) a method of contacting the carbon material with nitrogen dioxide gas.
[0020] As the friction material composition after adding the graphitic carbon particle is heat press formed, while compressive load is being applied to the graphitic carbon particle, the thermosetting resin contained in the friction material composition functioning as a binder is cured to form an outline of the friction material. As a result, the inside of the friction material is maintained the condition where a recovering force of the graphitic carbon particle is maintained therein.
[0021] The chipping of an edge of the friction material that occurs under the high speed and high load braking conditions is presumed to be generated based on cracks caused because of pores that are formed by decomposing the organic substance contained in the friction material because of the high temperature of the friction material due to the own friction heat caused by the high speed and high load breaking.
[0022] The friction material containing the graphitic carbon particle is such that the graphitic carbon particle with an effective recovering force functions to fill in the pores therearound to suppress the causation of the cracks that are the causes of the chipping.
[0023] Because the graphitic carbon particle is a carbon type lubricant and has high lubricating ability, there is a problem of the deterioration of the braking effectiveness under the high speed and high load braking conditions when the large amount of the graphitic carbon particle is added to the friction material composition in order to suppress the causes of the chipping. to the friction material of
[0024] Accordingly, the present invention, so as to suppress the aforementioned deterioration of the braking effectiveness under the high speed and high load braking conditions, 1-15 weight % of ferrous sulfide relative to the total amount of the friction material composition as a metal sulfide type lubricant is also added. Furthermore, 1-10 weight % of one or any combination of two or more items selected from the group consisting of an aluminum particle, an aluminum fiber, an alloy particle containing aluminum, and an alloy fiber containing aluminum relative to the total amount of the friction composition as the inorganic friction modifier, are added in one embodiment of the invention. 90% or more of
[0025] In the normal using range of the brake, the ferrous sulfide acts as a lubricant, and for the purpose of improving the braking effectiveness under the high speed and high load braking conditions in the present invention, the ferrous sulfide acts as the friction modifier.
[0026] Also, the aluminum and the alloy containing aluminum act as the friction modifier in order to improve the braking effectiveness by causing an adhesive friction under the high speed and high load braking conditions.
[0027] As the alloy containing 90% or more of aluminum an alloy such as aluminum-zinc type alloy, aluminum-copper type alloy, aluminummanganic type alloy, aluminum-silicon type alloy, aluminum-magnesium type alloy, aluminum-magnesium-silicon type alloy, aluminum-zinc-magnesium type alloy may be utilized.
[0028] If the aluminum-copper type alloy is needed to be used, the total amount of the copper component is designed to be less than 5 weight % relative to the total amount of the friction material composition.
[0029] In addition, in a view of reducing the environmental impac\t or load, the copper component is preferably not included in the friction material composition.
[0030] In the present invention, the friction material is made from the friction material composition as defined in the present claims as well as the binder, the fiber base material, the titanate, the lubricant, the inorganic friction modifier, the inorganic friction modifier, pH adjusting agent, and the filler normally used for the friction material.
[0031] The binder may be one or any combination of two or more of the conventionally used material for the friction material binder such as a straight phenolic resin, a resin modified by a cashew oil, a silicone oil, or various elastomers such as an acrylic rubber, an aralkyl modified phenolic resin obtained by reacting the phenolic compound, an aralkyl ethyl compound, and an aldehyde compound, a thermosetting resin dispersing such as various elastomer or fluoropolymer in the phenolic resin. The amount of the binder contained therein is preferably 4 - 12 weight %, more preferably 5 - 8 weight % relative to the total amount of the friction material composition.
[0032] The fiber base material may be one or any combination of two or more of the conventionally used organic fiber for the friction material containing such as an aramid fiber, a cellulose fiber, a poly-phenylene-benzobisoxazole (PBO) fiber, and/or an acrylic fiber. The amount of the fiber base material contained therein is preferably 1 - 7 weight %, more preferably 2 - 4 weight % relative to the total amount of the friction material composition.
[0033] The titanate is preferably in a plate like or indefinite shape having multiple convex portions and may be one or any combination of two or more of the conventionally used titanate for the friction material containing such as a potassium titanate, a lithium potassium titanate, and a magnesium potassium titanate. The amount of the titanate contained in the friction material composition is preferably 7 - 35 weight %, more preferably 17 - 25 weight % relative to the total amount of the friction material composition.
[0034] For the lubricant, other than the above-described graphitic carbon particle, the ferrous sulfide, the lubricant may be one or any combination of two or more of the lubricant conventionally used for the friction material such as the metal sulfide type lubricant such as a molybdenum disulfide, a zinc sulfide, a tin sulfide, an and a composite metal sulfide and the carbon type lubricant such as an artificial graphite, a natural graphite, a petroleum coke, an activated carbon, and a polyacryonitrile oxidized fiber pulverized powder. The amount of the lubricant contained in the friction material composition is preferably 2 - 21 weight %, more preferably 4 - 17 weight % relative to the total amount of the friction material composition.
[0036] For the inorganic friction modifier, other than the above-described aluminum particle, aluminum fiber, alloy particle containing aluminum, and alloy fiber 90 % or more of 90% or more of containing aluminum, the inorganic friction modifier may be one or any combination of two or more of the particle inorganic friction modifier such as a talc, a mica, a vermiculite, a triiron tetroxide, a calcium silicate hydrate, a glass bead, a magnesium oxide, a zirconium oxide, a zirconium silicate, γ-alumina, α-alumina, and a silicon carbide and a fiber inorganic friction modifier such as a wollastonite, the sepiolite , the basalt fiber, the glass fiber, the biosoluble artificial mineral fiber, and the rock wool, and one or any combination of two or more of the above may be used. The amount of the inorganic friction modifier contained therein, together with the above-described aluminum particle, alloy particle containing the aluminum, aluminum fiber, and alloy fiber containing the aluminum, is preferably 15 - 50 weight %, more preferably 20 - 45 weight % relative to the total amount of the friction material composition.
[0037] The organic friction modifier may be one or any combination of two or more of the organic friction modifiers conventionally used for the friction material such as a cashew dust, a pulverized powder of tire tread rubber, a vulcanized or an unvulcanized rubber powder of such as a nitrile rubber, an acrylic rubber, a silicone rubber, and a butyl rubber. The amount of the organic friction modifier contained therein is preferably 3 - 8 weight %, more preferably 4 - 7 weight % relative to the total amount of the friction material composition.
[0038] A calcium hydroxide which is conventionally utilized for the friction material may be used as the pH adjusting agent. The amount of the pH adjusting agent is preferably 2 - 6 weight %, more preferably 2 - 3 weight % relative to the total amount of the friction material composition.
[0039] As the reminders of the friction material composition, filler such as a barium sulfate and a calcium carbonate may be used.
[0040] The friction material of this invention used in the disc brake is manufactured through the mixing step of uniformly mixing the predetermined amount of friction material composition oriented therein using a mixer, the heat press forming step of heat press forming the obtained raw friction material mixture positioned in the heat forming die superposed on the separately pre-cleaned, surface treated, and adhesive applied back plate, the heat treatment step of heating the obtained molded product to complete the cure reaction of the binder, the electrostatic powder coating step of coating the powder coating thereon, the baking step of baking the coating, and the grinding step of forming the friction surface by the rotary grinding wheel. Also, after the heat press forming step, the heat treatment step performing both the coating step and baking step may be replaced before the grinding step.
[0041] As necessary, prior to the heat press forming step, the granulation step of granulating the raw friction material mixture, the kneading step of kneading the raw friction material, and the pre-forming step of forming an unfinished preformed article by positioning the raw friction material mixture or the granulation obtained through the granulation step and the kneaded article obtained through the kneading step into the pre-forming die, are performed, and after the heat press forming step, the scorching step is performed.
[EMBODIMENT]
[0042] In the following sections, the embodiments and the comparative examples are shown; however, this invention is not limited to the embodiments described below.
[0043] [Manufacturing Method for Friction Material in Embodiments 1-14 and Comparative Examples 1 - 3]
[0044] The friction material composition shown in TABLE 1 and TABLE 2 is mixed for 5 minutes by the Loedige mixer and is pressed in the forming die under 30MPa for 10 seconds to perform the preforming. This preforming product is superposed on the pre-cleaned, surface treated, adhesive coated steel back plate to form for 10 minutes in the heat forming die at the forming temperature of 150 centigrade under the forming pressure of 40MPa, to heat treatment (post-curing) for 5 hours at 200 centigrade, and to grind to form the friction surface for the disc brake pad of the automotive (Embodiments 1 - 14 and Comparative Examples 1 - 3).
[TABLE 1]
| Embodiments | |||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |
| Aralkyl Modified Phenolic Resin (Phenol Aralkyl resin) | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 |
| Straight Phenolic Resin | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| Copper Fiber | 3.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Aramid Fiber | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| Ferrous Sulfide | 0.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 0.5 | 1.0 | 15.0 |
| Molybdenum Disulfide | 5.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Graphitic Carbon | 1.0 | 0.5 | 2.0 | 3.0 | 5.0 | 10.0 | 3.0 | 3.0 | 3.0 |
| Petroleum Coke | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Graphite | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Potassium Hexatitanate (Indefinite Shape) | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 |
| Aluminum Particle | 0.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 0.0 | 0.0 | 0.0 |
| Aluminum - Zinc Alloy Particle | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Zirconium Oxide | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 |
| Triiron Tetroxide | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 |
| Zirconium Silicate | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| Mica | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 |
| Pulverized Powder of Tire Tread Rubber | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Cashew Dust | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
| Calcium Hydroxide | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| Barium Sulfate | 15.0 | 15.5 | 14.0 | 13.0 | 11.0 | 6.0 | 20.5 | 20.0 | 6.0 |
| Total | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
[TABLE 2]
| Embodiments | Comparative Examples | |||||||
| 10 | 11 | 12 | 13 | 14 | 1 | 2 | 3 | |
| Aralkyl Modified Phenolic Resin (Phenol Aralkyl Resin) | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 |
| Straight Phenolic Resin | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| Copper Fiber | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Aramid Fiber | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| Ferrous Sulfide | 17.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
| Molybdenum Disulfide | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Graphitic Carbon | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 0.3 | 12.0 | 0.0 |
| Petroleum Coke | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 3.0 |
| Graphite | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Potassium Hexatitanate (Indefinite Shape) | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 | 17.0 |
| Aluminum Particle | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 3.0 | 3.0 | 3.0 |
| Aluminum - Zinc Alloy Particle | 0.0 | 0.5 | 1.0 | 10.0 | 12.0 | 0.0 | 0.0 | 0.0 |
| Zirconium Oxide | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 | 25.0 |
| Triiron Tetroxide | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 |
| Zirconium Silicate | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| Mica | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 | 4.0 |
| Pulverized Powder of Tire Tread Rubber | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Cashew Dust | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
| Calcium Hydroxide | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 | 3.0 |
| Barium Sulfate | 4.0 | 15.5 | 15.0 | 6.0 | 4.0 | 15.7 | 4.0 | 13.0 |
| Total | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
[0045] In the resulted friction material, the braking effectiveness and wear resistance under the high speed and high load braking conditions were evaluated. The evaluation results are shown in the TABLE 3 and TABLE 4, and the evaluation standard is shown in the TABLE 5.
[TABLE 3]
| Embodiments | ||||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | ||
| Evaluation Result | Chipping | Ⓞ | Δ | ○ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ |
| Wear Resistance | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | ○ | ○ | Ⓞ | |
| Agressiveness against the Facing Member | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | ○ | ○ | ○ | |
| Speed and High Load Braking Performance | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | ○ | Δ | ○ | Ⓞ | |
| Braking Performance in the Normal Working Range | Ⓞ | Ⓞ | Ⓞ | Ⓞ | ○ | Δ | Δ | ○ | Ⓞ | |
[TABLE 4]
| Embodiments | Comparative Examples | ||||||||
| 10 | 11 | 12 | 13 | 14 | 1 | 2 | 3 | ||
| Evaluation Result | Chipping | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | × | Ⓞ | × |
| Wear Resistance | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Δ | Ⓞ | ○ | |
| Agressiveness against the Facing Member | Δ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | Ⓞ | |
| Speed and High Load Braking Performance | Ⓞ | ○ | Ⓞ | Ⓞ | Ⓞ | ○ | Δ | ○ | |
| Braking Performance in the Normal Working Range | Ⓞ | Ⓞ | Ⓞ | Ⓞ | ○ | Ⓞ | × | Ⓞ | |
[TABLE 5]
| Evaluation Items | Chipping | Wear Resistance | Agressiveness against the Mating Member | Effectiveness under High Speed and High Load Braking | Effectiveness in the Normal use Range |
| Evaluation Method | JASO C406 auto motor und sport (AMS), German Automobile Journal High Speed Pattern Simulation Test, 150% condition 240 km/h → 5km/h (Deceleration 0.6G) × 1 Cycle | JASO C406 Second Effect Test 50 km/h → 0 km/h Hydraulic Pressure (4MPa) | |||
| Maximum Width of the Chipping | Amount of Wear of Friction Material | Amount of Wear of the Mating Member | Average µ min value of Final Braking | Average µ of Five Cycle | |
| Ⓞ | none | 2.0mm or less | 10µm or less | 0.20 or more | 0.42 or more, less than0.46 |
| o | Less than 1.0mm | 2.0mm or more, less than 3.0mm | 10µm or more, less than 15µm | Less than 0.20, 0.15 or more | 0.38 or more, less than 0.42 |
| Δ | 1.0mm or more, less than 5.0mm | 3.0mm or more, less than 4.0mm | 15µm or more, less than 20µm | Less than 0.15, 0.10 or more | 0.34 or more, less than 0.38 |
| × | 5.0mm or more | 4.0mm or more | 20µm or more | Less than 0.10 | Less than 0.34 |
[0046] From the evaluation results of the TABLE 3 and TABLE 4, the friction material in the embodiments, although the compositions used therein has no copper component contained or has very minor amount, if ever contained, the friction material is expected to provide sufficient evaluation results. Therefore, no practical problem can be seen in the evaluation results.
[INDUSTRIAL APPLICABILITY]
[0047] According to the present invention, in the friction material utilized for disc brake pad, which is manufactured by forming the NAO friction material composition, the obtained friction material, while satisfying laws relating to the required amount of the content of the copper component contained therein, can suppress the chipping of the edge of the friction material that occurs under the high speed and high load braking conditions and further can suppress the deterioration of braking effectiveness, which provides an extremely practical and valuable solution to the friction material.
1. A NAO friction material which is a non-asbestos-organic friction material utilized for a disc brake pad, which is manufactured by forming a non-asbestos organic friction material composition comprising a copper component of less than 5 weight % in total relative to the total amount of the friction material composition, characterized in that said friction material composition comprises 0.5 - 10 weight % of a graphitic carbon particle having a graphitization degree of 80-95 % according to the X-ray analysis relative to the total amount of the friction material composition as a carbon type lubricant, and 1-15 weight % of ferrous sulfide relative to the total amount of the friction material composition as a metal sulfide type lubricant.
2. The friction material according to Claim 1, characterized in that said friction material composition contains 1 - 10 weight % of one or any combination of two or more items selected from the group consisting of an aluminum particle, an aluminum fiber, an alloy particle containing 90 % or more of aluminum, and an alloy fiber containing 90 % or more of aluminum relative to the total amount of the friction material composition as an inorganic friction modifier.
1. NAO-Reibungsmaterial, das ein asbestfreies organisches Reibungsmaterial zur Verwendung für einen Scheibenbremsbelag ist, welches durch Bilden einer asbestfreien organischen Reibungsmaterialzusammensetzung, umfassend einen Kupferbestandteil von weniger als 5 Gew.-%, bezogen auf die Gesamtmenge der Reibmaterialzusammensetzung, hergestellt ist, dadurch gekennzeichnet, dass die Reibungsmaterialzusammensetzung 0,5 - 10 Gew.-% von graphitartigen Kohlenstoffpartikeln mit einem gemäß Röntgenanalyse bestimmten Graphitisierungsgrad von 80 - 95 %, bezogen auf die Gesamtmenge der Reibungsmaterialzusammensetzung, als Schmiermittel vom Kohlenstofftyp, und 1 - 15 Gew.-% Eisen(II)-sulfid, bezogen auf die Gesamtmenge der Reibungsmaterialzusammensetzung, als Schmiermittel vom Metallsulfidtyp, umfasst.
2. Reibungsmaterial nach Anspruch 1, dadurch gekennzeichnet, dass die Reibungsmaterialzusammensetzung 1 - 10 Gew.-% eines oder einer beliebigen Kombination von zwei oder mehreren Bestandteilen enthält, ausgewählt aus der Gruppe bestehend aus einem Aluminiumteilchen, einer Aluminiumfaser, einem Legierungsteilchen, enthaltend 90 % oder mehr Aluminium, und einer Legierungsfaser, enthaltend 90 % oder mehr Aluminium, bezogen auf die Gesamtmenge der Reibmaterialzusammensetzung, als anorganischer Reibungsmodifikator.
1. Matériau de friction NAO qui est un matériau de friction organique non-amiante utilisé pour une plaquette de frein à disque, qui est fabriqué en formant une composition de matériau de friction organique non-amiante comprenant un composant de cuivre de moins de 5% en poids au total par rapport à la quantité totale de la composition de matériau de friction, caractérisé en ce que ladite composition de matériau de friction comprend 0,5 à 10% en poids d'une particule de carbone graphitique ayant un degré de graphitisation de 80 à 95% selon l'analyse aux rayons X par rapport à la quantité totale de la composition de matériau de friction en tant que lubrifiant de type carbone, et 1-15 % en poids de sulfure ferreux par rapport à la quantité totale de la composition de matériau de friction en tant que lubrifiant de type sulfure métallique.
2. Matériau de friction selon la revendication 1, caractérisé en ce que ladite composition de matériau de friction contient 1-10 % en poids d'un ou de toute combinaison de deux ou plusieurs éléments choisis parmi le groupe constitué par une particule d'aluminium, une fibre d'aluminium, une particule d'alliage contenant 90 % ou plus d'aluminium, et une fibre d'alliage contenant 90 % ou plus d'aluminium par rapport à la quantité totale de la composition de matériau de friction en tant que modificateur de friction inorganique.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
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