High-viscoelasticity low-noise friction material, brake pad and preparation method of high-viscoelasticity low-noise friction material

Abstract

The invention provides a high-viscoelasticity low-noise friction material, a brake pad and a preparation method of the high-viscoelasticity low-noise friction material. The high-viscoelasticity low-noise friction material is prepared from the following raw materials in parts by weight: 7 to 12 parts of organic binder, 10 to 25 parts of reinforcing material fiber, 10 to 20 parts of friction performance regulator, 15 to 25 parts of anti-wear lubricant, 4 to 10 parts of elastic toughening agent, 8 to 18 parts of friction increasing agent, 6 to 10 parts of porous material and 20 to 30 parts of space filler. A brake pad produced by the high-viscoelasticity low-noise friction material has the characteristics of high damping, low noise, high strength, high temperature resistance, wear resistance and the like, is comfortable to brake in the use process, is free of noise and long in service life, and meets the requirements of customers.

Description

Technical Field

[0001] The present invention relates to the technical field of friction materials, and particularly relates to a high viscoelastic low-noise friction material, a brake pad and a preparation method thereof. Background Art

[0002] Friction materials are widely used for various purposes. For example, braking devices or clutch devices require friction materials, and friction materials are used in the form of brake linings, disc pads, brake shoes, brake pads and clutch facings. Examples of suitable application fields are industrial machinery and transportation systems or vehicles, such as elevators, passenger cars, motorcycles, bicycles, trucks, rail vehicles, aircraft, luggage carts and cable cars.

[0003] However, existing friction materials still have a problem of high noise during braking, so it is necessary to develop a friction material with less noise. Summary of the Invention

[0004] The present invention provides a high viscoelastic low-noise friction material, a brake pad and a preparation method thereof, which solve the defect of high noise of existing friction materials during braking.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a high viscoelastic low-noise friction material, which comprises the following raw materials in parts by weight: 7-12 parts of an organic binder, 10-25 parts of a reinforcing material fiber, 10-20 parts of a friction performance regulator, 15-25 parts of an anti-wear lubricant, 4-10 parts of an elastic toughening agent, 8-18 parts of a wear-increasing agent, 6-10 parts of a porous material, and 20-30 parts of a space filler.

[0007] Preferably, the organic binder comprises, in parts by weight: 20-60 parts of an acrylic acid modified resin, 20-60 parts of a silicon-rubber modified resin, and 10-20 parts of an aralkyl modified resin.

[0008] Preferably, the reinforcing fiber comprises, in parts by weight: 30-50 parts of an aramid fiber, 15-30 parts of a mineral fiber, 20-40 parts of a brass fiber, and 10-25 parts of a copper fiber. The aramid fiber comprises at least one of p-phenylenediamine or terephthaloyl chloride; the mineral fiber comprises at least one of silicon dioxide, magnesium oxide, aluminum oxide, iron oxide or calcium oxide.

[0009] Preferably, the friction performance regulator comprises, in parts by weight: 40-60 parts of a cashew shell oil friction powder and 30-50 parts of potassium titanate.

[0010] Preferably, the anti-wear lubricant, by weight, comprises: 20-35 parts of metal sulfide, 30-60 parts of flake graphite, and 20-35 parts of calcined petroleum coke. The metal sulfide comprises at least one of bismuth sulfide, iron sulfide, tin sulfide, or zinc sulfide.

[0011] Preferably, the elastic toughening agent, by weight, comprises: 40-60 parts of tire powder and 30-50 parts of rubber powder.

[0012] Preferably, the friction increasing agent, by weight, comprises: 30-50 parts of zirconium silicate, 25-50 parts of zirconia, and 10-20 parts of alumina.

[0013] Preferably, the porous material is aluminum silicate hollow spheres.

[0014] Preferably, the space filler, by weight, comprises: 40-70 parts of barium sulfate, 20-40 parts of mica, and 15-30 parts of calcium hydroxide.

[0015] On the other hand, the present invention provides a brake pad comprising the above-mentioned high-viscoelastic low-noise friction material.

[0016] On yet another aspect, the present invention provides a method for preparing a brake pad, comprising the following preparation steps:

[0017] (1) Weighing: Weigh the materials according to the raw materials and parts by weight of the high-viscoelastic low-noise friction material for standby.

[0018] (2) Mixing: Put the weighed raw materials into a vertical mixer for mixing to form a mixed material, and the mixing time is 5-9 minutes.

[0019] (3) Pre-pressing: Weigh the corresponding weight of the mixed material according to the brake pad model, pour it into a pre-pressing mold, set the pre-pressing pressure to 120-200 kgf / cm 2 , and keep the pressure for 4-8 seconds to form a pre-pressed block.

[0020] (4) Hot pressing: Put the pre-pressed block and the steel back into a hot pressing mold, set the pre-pressing pressure to 250-320 kgf / cm 2 , the hot pressing temperature is 145-155 °C, exhaust for 2-4 seconds every 3-6 seconds of pressing, and the number of pressing and exhaust cycles is 5-8 times, and keep the pressure for 240-330 seconds.

[0021] (5) Heat treatment: Put the brake pad formed by the above hot pressing into a heat treatment furnace, the temperature in the furnace is 200 °C - 240 °C, bake for 6-7 hours, and then take out the brake pad and place it indoors until it cools to room temperature.

[0022] (6) High-temperature ablation: Put the above-cooled brake pads into a stepped heating furnace for stepped heating. The stepped heating temperatures are: 200 ± 10 °C, 240 ± 10 °C, 280 ± 10 °C, 320 ± 10 °C, 500 ± 10 °C, and each temperature is heated for 30 - 40 s;

[0023] (7) Post-processing: Then grind, chamfer, cut grooves, powder, attach a noise reduction sheet and rivet the above-heated brake pads according to technical requirements.

[0024] Advantages of the present invention: The organic binder of the high viscoelastic and low-noise friction material of the present invention uses different modified resin binders. The acrylic modified resin has high viscoelastic and high damping characteristics in the low-temperature section, the silicon-rubber modified resin has high viscoelastic and high damping characteristics in the high-temperature section, and the arylalkyl modified resin has high temperature resistance and decomposition resistance characteristics. Add several modified resins to the brake pads in an appropriate ratio, combine the advantages of several modified resins, and add porous materials, rubber powder, and various reinforcing fibers, so that the brake pads have the characteristics of high damping, low noise, high strength, high temperature resistance, wear resistance, etc. During use, the braking is comfortable, there is no noise, and the service life is long, meeting the requirements of customers. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a flowchart of a preparation method of a brake pad in the present invention;

[0027] Figure 2 It is a viscoelasticity data graph of acrylic modified resin, silicon-rubber modified resin and arylalkyl modified resin at different temperatures;

[0028] Figure 3 It is a TGA thermogravimetric analysis data graph of acrylic modified resin, silicon-rubber modified resin and arylalkyl modified resin at different temperatures;

[0029] Figure 4 It is a SAE J2521 noise analysis report graph of a brake pad using a common phenolic resin binder;

[0030] Figure 5 It is a SAE J2521 noise analysis report graph of a brake pad prepared with the high viscoelastic and low-noise friction material of Example 1;

[0031] Figure 6SAE J2521 noise analysis report diagram of the brake pads prepared with the high-viscoelastic and low-noise friction material of Example 2;

[0032] Figure 7 SAE J2521 noise analysis report diagram of the brake pads prepared with the high-viscoelastic and low-noise friction material of Example 3. Detailed implementation manners

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] A high-viscoelastic and low-noise friction material, by weight, comprises the following raw materials: 7-12 parts of an organic binder, 10-25 parts of a reinforcing material fiber, 10-20 parts of a friction property regulator, 15-25 parts of an anti-wear lubricant, 4-10 parts of an elastic toughening agent, 8-18 parts of an abrasion increasing agent, 6-10 parts of a porous material, and 20-30 parts of a space filler.

[0035] Preferably, the organic binder, by weight, comprises: 20-60 parts of an acrylic modified resin, 20-60 parts of a silicon-rubber modified resin, and 10-20 parts of an aralkyl modified resin.

[0036] Preferably, the reinforcing fiber, by weight, comprises: 30-50 parts of an aramid fiber, 15-30 parts of a mineral fiber, 20-40 parts of a brass fiber, and 10-25 parts of a copper fiber. The aramid fiber comprises at least one of p-phenylenediamine or terephthaloyl chloride; the mineral fiber comprises at least one of silicon dioxide, magnesium oxide, aluminum oxide, iron oxide or calcium oxide.

[0037] Preferably, the friction property regulator, by weight, comprises: 40-60 parts of a cashew shell oil friction powder and 30-50 parts of potassium titanate.

[0038] Preferably, the anti-wear lubricant, by weight, comprises: 20-35 parts of a metal sulfide, 30-60 parts of flake graphite, and 20-35 parts of calcined petroleum coke. The metal sulfide comprises at least one of bismuth sulfide, iron sulfide, tin sulfide or zinc sulfide.

[0039] Preferably, the elastic toughening agent, by weight, comprises: 40-60 parts of a tire powder and 30-50 parts of a rubber powder.

[0040] Preferably, the friction increasing agent, by weight, comprises: 30-50 parts of zirconium silicate, 25-50 parts of zirconia, and 10-20 parts of alumina.

[0041] Preferably, the porous material is a hollow aluminosilicate sphere.

[0042] Preferably, the space filler, by weight, comprises: 40-70 parts of barium sulfate, 20-40 parts of mica, and 15-30 parts of calcium hydroxide.

[0043] A brake pad comprises the above-mentioned high-viscoelastic and low-noise friction material.

[0044] A preparation method of a brake pad comprises the following preparation steps:

[0045] (1) Weighing materials: Weigh the raw materials of the high-viscoelastic and low-noise friction material according to the raw materials and parts by weight, and set aside for use.

[0046] (2) Mixing materials: Put the weighed raw materials into a vertical mixer for mixing to form a mixed material, and the mixing time is 5-9 minutes.

[0047] (3) Pre-pressing: Weigh the corresponding weight of the mixed material according to the brake pad model, pour it into a pre-pressing mold, set the pre-pressing pressure to 120-200 kgf / cm 2 , and keep the pressure for 4-8 seconds to form a pre-pressed block.

[0048] (4) Hot pressing: Put the pre-pressed block and the steel back into a hot pressing mold, set the pre-pressing pressure to 250-320 kgf / cm 2 , the hot pressing temperature is 145-155 °C, exhaust for 2-4 seconds every 3-6 seconds of pressing, the number of pressing and exhausting cycles is 5-8 times, and keep the pressure for 240-330 seconds.

[0049] (5) Heat treatment: Put the brake pad formed by the above hot pressing into a heat treatment furnace, the temperature in the furnace is 200 °C - 240 °C, bake for 6-7 hours, and then take out the brake pad and place it indoors until it cools to room temperature.

[0050] (6) High-temperature ablation: Put the cooled brake pad into a step-type heating furnace for step-type heating, and the step-type heating temperatures are: 200 ± 10 °C, 240 ± 10 °C, 280 ± 10 °C, 320 ± 10 °C, 500 ± 10 °C, and heat at each temperature for 30-40 seconds.

[0051] (7) Post-processing: Then grind, chamfer, cut grooves, powder, paste a sound-absorbing sheet and rivet the heated brake pad according to the technical requirements.

[0052] Example 1

[0053] A high-viscoelastic and low-noise friction material, by weight, comprises the following raw materials: 8 parts of an organic binder, 15 parts of a reinforcing material fiber, 10 parts of a friction property regulator, 17 parts of an anti-wear lubricant, 5 parts of an elastic toughening agent, 14 parts of an abrasion increasing agent, 6 parts of a porous material, and 25 parts of a space filler.

[0054] Preferably, the organic binder, by weight, comprises: 40 parts of an acrylic acid modified resin, 40 parts of a silicone-rubber modified resin, and 20 parts of an aralkyl modified resin.

[0055] Preferably, the reinforcing fiber, by weight, comprises: 50 parts of an aramid fiber, 20 parts of a mineral fiber, 20 parts of a brass fiber, and 10 parts of a copper fiber. The aramid fiber comprises p-phenylenediamine and terephthaloyl chloride; the mineral fiber comprises silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, and calcium oxide.

[0056] Preferably, the friction property regulator, by weight, comprises: 60 parts of a cashew shell oil friction powder and 40 parts of potassium titanate.

[0057] Preferably, the anti-wear lubricant, by weight, comprises: 25 parts of a metal sulfide, 40 parts of flake graphite, and 35 parts of calcined petroleum coke. The metal sulfide comprises bismuth sulfide, iron sulfide, tin sulfide, and zinc sulfide.

[0058] Preferably, the elastic toughening agent, by weight, comprises: 60 parts of a tire powder and 40 parts of a rubber powder.

[0059] Preferably, the abrasion increasing agent, by weight, comprises: 40 parts of zirconium silicate, 50 parts of zirconia, and 10 parts of aluminum oxide.

[0060] Preferably, the porous material is a hollow aluminosilicate sphere.

[0061] Preferably, the space filler, by weight, comprises: 60 parts of barium sulfate, 25 parts of mica, and 15 parts of calcium hydroxide.

[0062] Example 2

[0063] A high-viscoelastic and low-noise friction material, by weight, comprises the following raw materials: 8 parts of an organic binder, 15 parts of a reinforcing material fiber, 12 parts of a friction property regulator, 18 parts of an anti-wear lubricant, 6 parts of an elastic toughening agent, 10 parts of an abrasion increasing agent, 6 parts of a porous material, and 25 parts of a space filler.

[0064] Preferably, the organic binder, by weight, comprises: 25 parts of an acrylic acid modified resin, 60 parts of a silicone-rubber modified resin, and 15 parts of an aralkyl modified resin.

[0065] Preferably, by weight, the reinforcing fibers include: 55 parts of aramid fiber, 15 parts of mineral fiber, 20 parts of brass fiber, and 10 parts of copper fiber. The aramid fiber includes p-phenylenediamine and terephthaloyl chloride; the mineral fiber includes silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, and calcium oxide.

[0066] Preferably, by weight, the friction property regulator includes: 50 parts of cashew shell oil friction powder and 50 parts of potassium titanate.

[0067] Preferably, by weight, the anti-wear lubricant includes: 20 parts of metal sulfide, 40 parts of flake graphite, and 40 parts of calcined petroleum coke. The metal sulfide includes bismuth sulfide, iron sulfide, tin sulfide, and zinc sulfide.

[0068] Preferably, by weight, the elastic toughening agent includes: 50 parts of tire powder and 50 parts of rubber powder.

[0069] Preferably, by weight, the friction increasing agent includes: 40 parts of zirconium silicate, 45 parts of zirconia, and 15 parts of alumina.

[0070] Preferably, the porous material is a hollow alumina silicate sphere.

[0071] Preferably, by weight, the space filler includes: 60 parts of barium sulfate, 30 parts of mica, and 10 parts of calcium hydroxide.

[0072] Example 3

[0073] A high-viscoelastic and low-noise friction material, by weight, comprises the following raw materials: 10 parts of organic binder, 16 parts of reinforcing material fiber, 10 parts of friction property regulator, 16 parts of anti-wear lubricant, 7 parts of elastic toughening agent, 12 parts of friction increasing agent, 6 parts of porous material, and 23 parts of space filler.

[0074] Preferably, by weight, the organic binder includes: 40 parts of acrylic acid modified resin, 50 parts of silicone-rubber modified resin, and 10 parts of aralkyl modified resin.

[0075] Preferably, by weight, the reinforcing fibers include: 45 parts of aramid fiber, 25 parts of mineral fiber, 15 parts of brass fiber, and 15 parts of copper fiber. The aramid fiber includes p-phenylenediamine and terephthaloyl chloride; the mineral fiber includes silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, and calcium oxide.

[0076] Preferably, by weight, the friction property regulator includes: 45 parts of cashew shell oil friction powder and 55 parts of potassium titanate.

[0077] Preferably, the anti-wear lubricant, by weight, comprises: 15 parts of metal sulfide, 60 parts of flake graphite, and 25 parts of calcined petroleum coke. The metal sulfide includes bismuth sulfide, iron sulfide, tin sulfide, and zinc sulfide.

[0078] Preferably, the elastic toughening agent, by weight, comprises: 40 parts of tire powder and 60 parts of rubber powder.

[0079] Preferably, the friction increasing agent, by weight, comprises: 40 parts of zirconium silicate, 45 parts of zirconia, and 15 parts of alumina.

[0080] Preferably, the porous material is a hollow aluminosilicate sphere.

[0081] Preferably, the space filler, by weight, comprises: 65 parts of barium sulfate, 20 parts of mica, and 15 parts of calcium hydroxide.

[0082] Example 4

[0083] A brake pad comprises the high-viscoelastic and low-noise friction material of Example 1, Example 2, or Example 3.

[0084] Example 5

[0085] A preparation method of a brake pad comprises the following preparation steps:

[0086] (1) Weighing ingredients: According to the raw materials and parts by weight of the high-viscoelastic and low-noise friction material of Example 1, Example 2, or Example 3, weigh the materials and set aside.

[0087] (2) Mixing: Put the weighed raw materials into a vertical mixer for mixing to form a mixed material, and the mixing time is 7 minutes.

[0088] (3) Pre-pressing: Weigh the corresponding weight of the mixed material according to the brake pad model, pour it into a pre-pressing mold, set the pre-pressing pressure to 180 kgf / cm 2 , and keep the pressure for 6 seconds to form a pre-pressed block.

[0089] (4) Hot pressing: Put the pre-pressed block and the steel back into a hot pressing mold, set the hot pressing pressure to 290 kgf / cm 2 , the hot pressing temperature to 150 °C, exhaust for 3 seconds every 5 seconds of pressing, and the number of pressing and exhaust cycles is 7 times, and keep the pressure for 300 seconds.

[0090] (5) Heat treatment: Put the brake pad formed by the above hot pressing into a heat treatment furnace, the temperature in the furnace is 225 °C, bake for 6 hours, and then take out the brake pad and place it indoors until it cools to room temperature.

[0091] (6) High-temperature ablation: The above-cooled brake pads are placed in a stepped heating furnace for stepped heating. The stepped heating temperatures are: 200°C, 240°C, 280°C, 320°C, 500°C, and each temperature is heated for 30 s;

[0092] (7) Post-processing: Then, the above-heated brake pads are ground, chamfered, grooved, powdered, sound-absorbing sheets are pasted, and riveted according to technical requirements, and packaged to obtain brake pads.

[0093] Such as Figure 2 and Figure 3 , for the organic binder of the high viscoelastic and low-noise friction material of the present invention, different modified resin binders are used. The acrylic modified resin has high viscoelastic and high damping characteristics in the low-temperature section, the silicon-rubber modified resin has high viscoelastic and high damping characteristics in the high-temperature section, and the aralkyl modified resin has high temperature resistance and decomposition resistance characteristics. Several modified resins are added to the brake pads in appropriate proportions, combining the advantages of several modified resins, and adding porous materials, rubber powder, and various reinforcing fibers, so that the brake pads have the characteristics of high damping, low noise, high strength, high temperature resistance, and wear resistance. During use, the braking is comfortable, there is no noise, and the service life is long, meeting the requirements of customers.

[0094] Figure 3 The aralkyl, acrylic acid, and silicon-rubber in Figure 3 respectively represent aralkyl modified resin, acrylic modified resin, and silicon-rubber modified resin,

[0095] Noise test

[0096] The high viscoelastic and low-noise friction materials of Example 1, Example 2, and Example 3 are respectively prepared into brake pads through the preparation method of the brake pads in Example 5, and are respectively subjected to the SAE J2521 brake dynamometer noise test with the brake pads using ordinary phenolic resin binder. The specific noise analysis report is as Figures 4 - 7 .

[0097] Refer to the test comparison data records of each embodiment shown in the appendix Figures 4 to 7 . From the test results, the conclusion is drawn:

[0098] In Example 1, the acrylic modified resin and the silicon-rubber modified resin are in a ratio of 1:1. The brake pads prepared by this formula can effectively adjust the NVH performance of the material, and Figure 5 Comparing the SAE J2521 noise analysis report diagram of the brake pads prepared from the high viscoelastic and low-noise friction material of Example 1 with Figure 4 the SAE J2521 noise analysis report diagram of the brake pads with ordinary phenolic resin binder, the cold and hot state noise incidence rates are significantly reduced, and the improvement effect is obvious.

[0099] In Example 2, the ratio of acrylic modified resin to silicone-rubber modified resin is 2.5:6. The brake pads prepared with this formulation can effectively adjust the NVH performance of the material, and Figure 6 The SAE J2521 noise analysis report diagram of the brake pads prepared with the high viscoelastic and low-noise friction material of Example 2 is compared with Figure 4 the SAE J2521 noise analysis report diagram of the brake pads with ordinary phenolic resin binder. The incidence of hot-state noise is further reduced, and the improvement effect is obvious.

[0100] In Example 3, the proportion of the organic binder is increased and the ratio of acrylic modified resin to silicone-rubber modified resin is 4:5. The brake pads prepared with this formulation can effectively adjust the NVH performance of the material, and Figure 7 The SAE J2521 noise analysis report diagram of the brake pads prepared with the high viscoelastic and low-noise friction material of Example 3 is compared with Figure 4 the SAE J2521 noise analysis report diagram of the brake pads with ordinary phenolic resin binder. The incidence of cold-state noise is further reduced, and the improvement effect is obvious.

[0101] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-viscoelastic and low-noise friction material, characterized in that, By weight, it includes the following raw materials: 7-12 parts of organic binder, 10-25 parts of reinforcing material fiber, 10-20 parts of friction performance regulator, 15-25 parts of anti-wear lubricant, 4-10 parts of elastic toughening agent, 8-18 parts of abrasion-increasing agent, 6-10 parts of porous material, and 20-30 parts of space filler; Among them, the organic binder, by weight, includes: 20-60 parts of acrylic acid modified resin, 20-60 parts of silicone-rubber modified resin, and 10-20 parts of aralkyl modified resin.

2. The highly viscoelastic and low-noise friction material according to claim 1, wherein The reinforcing fiber, by weight, includes: 30-50 parts of aramid fiber, 15-30 parts of mineral fiber, 20-40 parts of brass fiber, and 10-25 parts of red copper fiber.

3. The highly viscoelastic and low-noise friction material according to claim 1, characterized in that The friction performance regulator, by weight, includes: 40-60 parts of cashew shell oil friction powder and 30-50 parts of potassium titanate.

4. A high-viscoelastic and low-noise friction material according to claim 1, characterized in that, The anti-wear lubricant, by weight, includes: 20-35 parts of metal sulfide, 30-60 parts of flake graphite, and 20-35 parts of calcined petroleum coke.

5. The high-viscoelastic and low-noise friction material according to claim 1, wherein The elastic toughening agent, by weight, includes: 40-60 parts of tire powder and 30-50 parts of rubber powder.

6. The high-viscoelastic and low-noise friction material according to claim 1, wherein The abrasion-increasing agent, by weight, includes: 30-50 parts of zirconium silicate, 25-50 parts of zirconia, and 10-20 parts of alumina.

7. The high-viscoelastic and low-noise friction material according to claim 1, wherein The porous material is aluminum silicate hollow sphere.

8. The highly viscous and elastic low-noise friction material according to claim 1, wherein The space filler, by weight, includes: 40-70 parts of barium sulfate, 20-40 parts of mica, and 15-30 parts of calcium hydroxide.

9. Brake pads, characterized in that, It includes the high-viscoelastic and low-noise friction material as described in any one of claims 1-8.

10. A method for preparing a brake pad, characterized in that, It includes the following preparation steps: (1) Weighing: Weigh the materials according to the raw materials and weight parts of the high-viscoelastic and low-noise friction material for standby; (2) Mixing: Put the weighed raw materials into a vertical mixer for mixing to form a mixed material, and the mixing time is 5-9 minutes; (3) Preloading: Weigh the corresponding weight of the mixture according to the brake pad model, pour it into the preloading mold, set the preloading pressure to 120 - 200 kgf / cm 2 , keep the pressure for 4 - 8 s to form a preloaded block; (4) Hot pressing: Put the pre-pressed block and the steel back into the hot pressing die, set the hot pressing pressure to 250 - 320 kgf / cm 2 , the hot pressing temperature is 145 - 155 °C, exhaust air for 2 - 4 s every 3 - 6 s of pressing, the number of pressing and exhaust cycles is 5 - 8 times, and the pressure holding time is 240 - 330 s; (5) Heat treatment: Put the above-mentioned brake pads after hot pressing into a heat treatment furnace, the temperature in the furnace is 200°C - 240°C, bake for 6-7 hours, and then take out the brake pads and place them indoors until they cool to room temperature; (6) High-temperature ablation: Put the above-mentioned cooled brake pads into a stepped heating furnace for stepped heating. The stepped heating temperatures are: 200±10°C, 240±10°C, 280±10°C, 320±10°C, 500±10°C, and each temperature is heated for 30-40 seconds; (7) Post-processing: Then grind, chamfer, groove, powder, paste a sound-absorbing sheet and rivet the above-mentioned heated brake pads according to technical requirements.

Images