A brake pad and a method of manufacturing the same

Abstract

The application discloses a brake pad and a preparation method thereof, and aims at solving the problems of a large amount of high-temperature grinding dust and the decline of the friction coefficient of the brake pad during continuous braking under high speed and high load. The brake pad comprises a friction material and a supporting seat. The friction material component comprises 65-75 wt% of a matrix component, 3-5 wt% of a matrix strengthening component, 15-25 wt% of a friction component, and 6-15 wt% of a lubricating component. The matrix component is beryllium bronze powder or aluminum bronze powder. The matrix strengthening component is metal powder. The friction component is ceramic whisker. The lubricating component is solid lubricant. The beryllium bronze powder or aluminum bronze powder material has a high thermal conductivity coefficient, and the generated grinding dust has a low temperature. The ceramic whisker makes the brake pad have a high and stable friction coefficient, and the generated grinding dust is less and has a low temperature. The lubricating component improves the wear resistance, anti-decline, and high-temperature friction stability of the brake pad, and simultaneously reduces the noise during work.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of brake pads of brake systems, and particularly relates to a brake pad and a preparation method thereof. BACKGROUND

[0002] The intelligent and mechanized construction of coal mines in China is accelerating, especially in flammable and explosive mines. Single-track hoists are used to transport materials, equipment and equipment parts weighing less than 5 tons in underground fully-mechanized mining, which improves transportation efficiency, improves underground working environment and reduces labor intensity. However, due to the requirements of underground explosion prevention and space limitations, if a large amount of high-temperature grinding dust is generated by the brake pad friction during the braking process of the single-track hoist, and the surface temperature of the brake pad is too high, it will cause the explosion of flammable gas or dust. Generally, the increase of load or speed of the single-track hoist leads to the increase of braking energy, and the temperature of the conventional brake pad in the working state rises sharply, generating a large amount of high-temperature grinding dust, which is easy to cause mine explosion and other major accidents. High braking energy will also cause the friction coefficient of the friction material to decrease and the braking force to be insufficient. In order to improve the carrying capacity of the single-track hoist, relax the use conditions and increase the transportation speed, the development of a new generation of single-track hoist is imminent, and the performance requirements of the braking system are also correspondingly improved. SUMMARY

[0003] The application aims to solve the problem of a large amount of high-temperature grinding dust generated by the brake pad and the decline of the friction coefficient of the brake pad during continuous braking under high speed and high load, and provides a brake pad and a preparation method thereof.

[0004] In a first aspect, a brake pad adopts the following technical scheme:

[0005] A brake pad comprises a friction material and a support seat; the friction material component comprises 65-75wt% base component, 3-5wt% base strengthening component, 15-25wt% friction component and 6-15wt% lubricating component;

[0006] The base component is beryllium bronze powder or aluminum bronze powder;

[0007] The base strengthening component is a metal powder;

[0008] The friction component is a ceramic whisker;

[0009] The lubricating component is a solid lubricant.

[0010] In the above technical solution, the beryllium bronze powder or aluminum bronze powder material has a high thermal conductivity, so that the temperature of the abrasive particles generated by the impact and friction of the brake pad is low; at the same time, the beryllium bronze powder or aluminum bronze powder compound is stable, has a high melting point, and is resistant to oxidation. The addition of ceramic whiskers in the friction material can improve the explosion-proof performance of the material, and the friction material has stable friction performance, high mechanical strength, and good thermal decay and thermal recovery performance, so that the brake pad has a high and stable friction coefficient; the addition of ceramic whiskers makes the brake pad have less abrasive and low temperature, and is suitable for high explosion-proof environment application in the mine. The addition of the lubricating component improves the wear resistance, anti-decay, and high-temperature friction stability of the brake pad, and at the same time reduces the noise generated by the brake pad during operation.

[0011] Preferably, the matrix strengthening component is one or more of tin powder, zinc powder, chromium powder, and manganese powder; and the particle size is 200-250 mesh.

[0012] In the above technical solution, the beryllium bronze powder or aluminum bronze powder is a copper-based alloy, and a small amount of tin powder, zinc powder, chromium powder, or manganese powder is added to increase the fluidity of the alloy, adjust the plasticity and hardness of the alloy, and improve the impact toughness of the brake pad, thereby further improving the friction resistance of the brake pad.

[0013] Preferably, the ceramic whisker is one or more of silicon nitride, potassium titanate, and aluminum oxide; and the particle size is 300-350 mesh.

[0014] Preferably, the solid lubricant is one or more of lead oxide, bismuth sulfide, and boron nitride; and the particle size is 200-250 mesh.

[0015] Preferably, the thickness of the support seat is 3-5 mm, the material is carbon structural steel Q235, and the surface is plated with copper 3-10 μm.

[0016] In the above technical solution, the parameters of the support seat are limited, the yield strength of the material is not less than 235 MPa, which meets the strength requirement of the brake pad; the surface of the support seat is plated with copper, which has good affinity with the solder, so that the support seat and the friction material are combined more closely.

[0017] Preferably, the friction material and the support seat are welded by solder.

[0018] Preferably, the solder component includes 5-15 wt% low-density metal powder and 85-95 wt% copper powder; the low-density metal powder is one or more of molybdenum, zinc, lead, tin, and manganese; and the particle size of the solder is 500-600 mesh.

[0019] In the technical scheme, the solder and the friction material obtained by mixing the low-density metal powder and the copper powder have good affinity with the support seat, and the friction material and the support seat are tightly welded to form a whole, and meanwhile, the support seat enhances the impact strength of the brake pad to avoid cracks and damage of the brake pad due to overload of the impact strength.

[0020] In a second aspect, a preparation method of a brake pad comprises the following technical scheme.

[0021] A preparation method of a brake pad comprises the following steps.

[0022] Step 1), the base component, the base strengthening component and the friction component are mixed according to the formula amount to obtain a mixture.

[0023] Step 2), the lubricating component is mixed with the mixture obtained in step 1) to obtain the friction material.

[0024] Step 3), the low-density metal powder and the copper powder are mixed according to the formula amount to obtain the solder.

[0025] Step 4), the support seat is placed in a mold, 0.5-1.5mm of the solder is laid on the support seat, and 15-25mm of the friction material is laid on the solder, and a compact is obtained by pressing under a pressure of 10-16MPa.

[0026] Step 5), the compact obtained in step 4) is sintered, and 3.5-7.5KN is applied to the friction material, and a brake pad is obtained after cooling.

[0027] In the technical scheme, the base component, the base strengthening component and the friction component are mixed, and then the lubricating component is added, which prevents the particle size of the lubricating component from being damaged during high-speed mixing and reduces the mixing time; the solder is laid on the support seat, and the friction material is laid on the solder, and the compact is obtained by pressing, and the friction material and the support seat are tightly welded together during high-temperature sintering.

[0028] Preferably, in the sintering process of step 5), the protective gas is 15-25% hydrogen and 75-85% inert gas, the heating rate is 15-25℃ / min, the temperature is increased in steps to 400℃, 500℃, 600℃ and 700℃, and the temperature is maintained for 10-20min respectively, the sintering temperature is 750-850℃, and the holding time is 1-3h.

[0029] By adopting the technical scheme, in a reducing atmosphere, oxidation of the alloy at high temperature is prevented, the heating rate and the step heating mode are controlled, and the situation of uncooked material caused by uneven heating of the material due to too fast temperature rise is avoided. The pressure applied on the friction material makes the friction material and the support seat tightly welded, thereby enhancing the strength of the brake pad. DETAILED DESCRIPTION

[0030] The application will be further described in conjunction with the examples. For the sake of simple description, all alternative technical features and embodiments included in the application cannot be enumerated in this document, and therefore, any technical feature and embodiment in the examples should be known by those skilled in the art that the protection scope of the application includes any alternative technical feature and embodiment taken by those skilled in the art without creative labor. Specifically, any technical feature in the application or any combination of two or more technical features provided by the application should be within the protection scope of the application. If the specific technology and conditions are not specified in the examples, the technology and conditions described in the literature in the art or according to the product manual are used, and if the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be purchased in the market.

[0031] In the following examples, the base strengthening component is a mixed component of tin powder, zinc powder, chromium powder and manganese powder mixed with any raw material and in any proportion;

[0032] The ceramic whisker is a mixed component of silicon nitride, potassium titanate and aluminum oxide mixed with any raw material and in any proportion;

[0033] The solid lubricant is a mixed component of lead oxide, bismuth sulfide and boron nitride mixed with any raw material and in any proportion;

[0034] The solder component includes 5-15 wt% of low-density metal powder and 85-95 wt% of copper powder; the low-density metal powder is a mixed component of molybdenum, zinc, lead, tin and manganese mixed with any raw material and in any proportion.

[0035] In the following examples, the aluminum bronze powder and beryllium bronze powder used in the base component are as follows:

[0036] The aluminum bronze powder is produced by Jinjiang Spraying Material Co., Ltd. in Jinzhou, with a mesh size of 325, containing 90 wt% of copper and 10 wt% of aluminum.

[0037] The beryllium bronze powder is produced by Dongguan Jingyan Powder Technology Co., Ltd., with a mesh size of 325, containing 2.5 wt% of beryllium and a small amount of nickel, chromium, titanium and other elements, and the rest is copper.

[0038] Example 1

[0039] The brake pad provided in the embodiment 1 comprises 15wt% tin powder and 85wt% copper powder, the particle size of the solder is 500 mesh; the friction material comprises 67wt% of the matrix component, 3wt% of the matrix strengthening component, 20wt% of the friction component and 10wt% of the lubricating component; wherein the matrix component is beryllium bronze powder; the matrix strengthening component comprises 1 part of zinc powder and 2 parts of manganese powder by weight, and the particle size is 250 mesh; the friction component comprises 3 parts of silicon nitride whisker and 1 part of potassium titanate whisker by weight, and the particle size is 300 mesh; the lubricating component comprises 4 parts of manganese sulfide and 1 part of boron nitride by weight, and the particle size is 250 mesh.

[0040] The support seat has a thickness of 3mm and is made of Q235, and the surface is plated with copper of 3μm.

[0041] The embodiment 1 provides a preparation method of a brake pad, comprising the following steps:

[0042] Step 1), the beryllium bronze powder, zinc powder, manganese powder, silicon nitride whisker and potassium titanate whisker are weighed according to the formula amount, and are uniformly mixed by using a high-speed mixer, the rotating speed is 500rpm, and the mixing time is 15min;

[0043] Step 2), the formula amount of manganese sulfide and boron nitride is mixed with the mixture obtained in step 1) again by using a three-dimensional motion mixer, the mixing rotating speed is 60rpm, the mixing time is 60min, and the friction material is obtained;

[0044] Step 3), the tin powder and the ultra-fine copper powder are weighed according to the formula amount and are mixed by using a three-dimensional motion mixer, the mixing rotating speed is 60rpm, the mixing time is 60min, and the solder is obtained;

[0045] Step 4), the support seat is placed in the mold, 1mm of the solder mixed powder is laid on the support seat, and 15mm of the friction material is laid on the solder, and a compact is obtained by pressing under the condition that the pressure is 12MPa;

[0046] Step 5), the compact obtained in step 4) is sintered, the protective gas is 15% hydrogen and 85% nitrogen, the heating rate is 15℃ / min, the temperature is increased in steps to 400℃, 500℃, 600℃ and 700℃, and the temperature is kept for 10min, the sintering temperature is 830℃, the temperature is kept for 2h, and 5KN is applied to the compact in the sintering process, and the brake pad is obtained after cooling.

[0047] Embodiment 2

[0048] The brake pad provided in the embodiment 2 has a solder of 10wt% manganese powder and 90wt% copper powder, and the particle size of the solder is 550 mesh; the friction material contains 67wt% of the matrix component, 3wt% of the matrix strengthening component, 20wt% of the friction component, and 10wt% of the lubricating component; wherein the matrix component is aluminum bronze powder; the matrix strengthening component contains 1 part of chromium powder and 2 parts of tin powder in terms of weight parts, and the particle size is 225 mesh; the friction component contains 1 part of aluminum oxide whisker and 1 part of potassium titanate whisker in terms of weight parts, and the whisker particle size is 350 mesh; the lubricating component contains 2 parts of bismuth sulfide and 3 parts of boron nitride in terms of weight parts, and the particle size is 225 mesh.

[0049] The support seat has a thickness of 4mm and is made of Q235, and the surface is plated with copper of 6μm.

[0050] The embodiment 2 provides a preparation method of a brake pad, which comprises the following steps:

[0051] In step 1), aluminum bronze powder, chromium powder, tin powder, aluminum oxide whisker and potassium titanate whisker are weighed according to the formula amount, and are uniformly mixed by using a high-speed mixer at a rotating speed of 500rpm for 15min;

[0052] In step 2), the formula amount of bismuth sulfide and boron nitride is mixed with the mixture obtained in step 1) by using a three-dimensional motion mixer again, and the mixing rotating speed is 60rpm; the mixing time is 60min, and the friction material is obtained;

[0053] In step 3), manganese powder and ultra-fine copper powder are weighed according to the formula amount and are mixed by using a three-dimensional motion mixer, the mixing rotating speed is 60rpm, and the mixing time is 60min, and the solder is obtained;

[0054] In step 4), the support seat is placed in the mold, 1.5mm of the solder mixed powder is laid on the support seat, and 20mm of the friction material is laid on the solder, and the green body is obtained by pressing and forming under the pressure of 14MPa;

[0055] In step 5), the green body obtained in step 4) is sintered, the protective gas is 20% hydrogen and 80% nitrogen, the heating rate is 20℃ / min, the temperature is increased in steps to 400℃, 500℃, 600℃ and 700℃, and the temperature is kept for 15min, the sintering temperature is 850℃, the temperature keeping time is 2h, and 5KN is applied to the green body in the sintering process, and the brake pad is obtained after cooling.

[0056] Embodiment 3

[0057] The brake pad provided in this embodiment 3, the solder is 5wt% tin powder, 95wt% 600 mesh ultra-fine copper powder; the friction material contains 65wt% of the matrix component, 5wt% of the matrix strengthening component, 20wt% of the friction component, 10wt% of the lubricating component; wherein the matrix component is beryllium bronze powder; the matrix strengthening component contains 1 part of chromium powder and 2 parts of manganese powder by weight, and the particle size is 200 mesh; the friction component contains 5 parts of alumina whisker and 6 parts of potassium titanate whisker by weight, and the whisker particle size is 325 mesh; the lubricating component contains 1 part of manganese sulfide and 3 parts of boron nitride by weight, and the particle size is 200 mesh.

[0058] The support seat has a thickness of 5 mm and is made of Q235, and the surface is plated with copper to 10 μm.

[0059] The preparation method of the brake pad provided in this embodiment 3 comprises the following steps:

[0060] Step 1), the beryllium bronze powder, chromium powder, manganese powder, alumina whisker and potassium titanate whisker are weighed according to the formula amount and uniformly mixed by using a high-speed mixer, the rotating speed is 500 rpm, and the mixing time is 15 min;

[0061] Step 2), the formula amount of manganese sulfide and boron nitride is mixed with the mixture obtained in step 1) again by using a three-dimensional motion mixer, the mixing rotating speed is 60 rpm, the mixing time is 60 min, and the friction material is obtained;

[0062] Step 3), the tin powder and ultra-fine copper powder are weighed according to the formula amount and mixed by using a three-dimensional motion mixer, the mixing rotating speed is 60 rpm, the mixing time is 60 min, and the solder is obtained;

[0063] Step 4), the support seat is placed in the mold, 1 mm of the solder is laid on the support seat, and 25 mm of the friction material is laid on the solder, and the green body is obtained by pressing under the pressure of 16 MPa;

[0064] Step 5), the green body obtained in step 4) is sintered, the protective gas is 25% hydrogen and 75% nitrogen, the heating rate is 25 ℃ / min, the temperature is increased to 400 ℃, 500 ℃, 600 ℃ and 700 ℃ by using the stepwise heating mode, the temperature is kept for 20 min, the sintering temperature is 850 ℃, the temperature is kept for 1 h, the green body is applied with 3.5 KN during the sintering process, and the brake pad is obtained after cooling.

[0065] Embodiment 4

[0066] The brake pad provided in this embodiment 4 is prepared from 5wt% zinc powder and 95wt% 500-mesh ultra-fine copper powder as the solder; the friction material comprises 70wt% base component, 4wt% base strengthening component, 18wt% friction component and 8wt% lubricating component; wherein the base component is beryllium bronze powder; the base strengthening component comprises 1 part of chromium powder and 2 parts of manganese powder in terms of weight of the base strengthening component, and the particle size is 200 mesh; the friction component comprises 1 part of alumina whisker and 2 parts of potassium titanate whisker in terms of weight of the friction component, and the whisker particle size is 325 mesh; the lubricating component comprises 3 parts of manganese sulfide and 1 part of boron nitride in terms of weight of the lubricating component, and the particle size is 200 mesh.

[0067] The support seat has a thickness of 5 mm and is made of Q235, and the surface is plated with copper to a thickness of 10 μm.

[0068] The preparation method of the brake pad provided in this embodiment 4 comprises the following steps:

[0069] In step 1), the beryllium bronze powder, chromium powder, manganese powder, alumina whisker and potassium titanate whisker are weighed according to the formula amount, mixed uniformly by using a high-speed mixer, the rotating speed is 500 rpm, and the mixing time is 15 min.

[0070] In step 2), the formula amount of manganese sulfide and boron nitride is mixed again uniformly by using a three-dimensional motion mixer with the mixture obtained in step 1), the mixing rotating speed is 60 rpm, the mixing time is 60 min, and the friction material is obtained.

[0071] In step 3), the zinc powder and ultra-fine copper powder are weighed according to the formula amount and mixed by using a three-dimensional motion mixer, the mixing rotating speed is 60 rpm, the mixing time is 60 min, and the solder is obtained.

[0072] In step 4), the support seat is placed in the mold, 1 mm of the solder is laid on the support seat, and 25 mm of the friction material is laid on the solder, and then the pressure forming is carried out under the pressure of 15 MPa to obtain a compact;

[0073] In step 5), the compact obtained in step 4) is sintered, the protective gas is 20% hydrogen and 80% nitrogen, the heating rate is 25 ℃ / min, the temperature is increased in steps to 400 ℃, 500 ℃, 600 ℃ and 700 ℃, and the temperature is kept for 20 min, the sintering temperature is 850 ℃, the temperature keeping time is 3 h, and the compact is subjected to a force of 7.5 KN during the sintering process, and the brake pad is obtained after cooling.

[0074] The brake pads provided in embodiments 5-7 are different from the brake pad of embodiment 4 in that the components of the friction material are shown in Table 1.

[0075] Table 1

[0076]

[0077] Comparative Example 1

[0078] Comparative Example 1

[0079] Comparative Example 1 provides a brake pad which is different from Example 4 in that the base strengthening component in Comparative Example 1 is replaced by the base component in equal amount, and other components and preparation methods remain unchanged.

[0080] Comparative Example 2

[0081] Comparative Example 2 provides a brake pad which is different from Example 4 in that the friction component in Comparative Example 2 is replaced by the base component in equal amount, and other components and preparation methods remain unchanged.

[0082] Comparative Example 3

[0083] Comparative Example 3 provides a brake pad which is different from Example 4 in that the lubricating component in Comparative Example 3 is replaced by the base component in equal amount, and other components and preparation methods remain unchanged.

[0084] Comparative Example 4

[0085] Comparative Example 4 provides a brake pad which is different from Example 4 in that the zinc powder in the solder is replaced by ultra-fine copper powder in equal amount, and other components and preparation methods remain unchanged.

[0086] Comparative Example 5

[0087] Comparative Example 5 provides a brake pad which is different from Example 4 in that the ultra-fine copper powder in the solder is replaced by zinc powder in equal amount, and other components and preparation methods remain unchanged.

[0088] Comparative Example 6

[0089] Comparative Example 6 provides a brake pad which is different from Example 4 in that the preparation method of the brake pad provided in Comparative Example 5, in the sintering process, uses continuous one-time heating to 850°C sintering temperature.

[0090] Performance Test

[0091] Parking brake tests were performed on Examples 1-7 and Comparative Examples 1-6, and the friction coefficient, maximum loss, maximum brake temperature, and shear strength of the brake pad were tested, and the performance test data is shown in Table 2 below.

[0092] Table 2

[0093]

[0094] From the above test results, it is known that: 1. When the base strengthening component is replaced by the base component in equal amount, the strength of the brake pad prepared is significantly reduced. 2. When the friction component is replaced by the base component in equal amount, the friction performance of the brake pad prepared is significantly reduced. 3. When the lubricating component is replaced by the base component in equal amount, the friction performance of the brake pad prepared is significantly reduced, the highest braking temperature is too high, and the maximum wear is significantly increased. 4. After the solder component is replaced by a single component, the welding performance between the friction material and the support seat is affected, resulting in a decrease in the overall strength of the brake pad, and under high speed and high pressure, there is a risk of overall falling off between the friction material and the support seat. 5. When the segmented sintering is replaced by one-time temperature sintering, due to insufficient sintering time and poor furnace temperature uniformity, volatile components in the friction material may not be discharged, thereby causing pores in the material, the material is relatively loose, the friction coefficient is increased, and the strength is low.

[0095] Other variations and modifications can be made to the above-described embodiments within the scope of the present application. It is not necessary for all aspects of the application to be implemented or necessary for the application to achieve its advantages. The embodiments described above are illustrative, but not restrictive. Other variations and modifications can be made to the above-described embodiments within the scope of the present application.

Claims

1. A brake pad, characterized in that, It includes friction material and support base; the friction material composition includes 65-75wt% matrix component, 3-5wt% matrix reinforcing component, 15-25wt% friction component, and 6-15wt% lubricating component; The matrix component is beryllium bronze powder or aluminum bronze powder; The matrix strengthening component is one or more of tin powder, zinc powder, chromium powder, and manganese powder; The friction component is a ceramic whisker, which is one or more of silicon nitride, potassium titanate, and aluminum oxide. The lubricating component is a solid lubricant; The friction material and the support base are welded together using solder, the solder composition including 5-15wt% low-density metal powder and 85-95wt% copper powder; the low-density metal powder is one or more of molybdenum, zinc, lead, tin and manganese.

2. A brake pad according to claim 1, characterized in that, The particle size of the matrix reinforcing component is 200-250 mesh.

3. A brake pad according to claim 1, characterized in that, The ceramic whiskers have a particle size of 300-350 mesh.

4. A brake pad according to claim 1, characterized in that, The solid lubricant is one or more of lead oxide, bismuth sulfide, and boron nitride; the particle size is 200-250 mesh.

5. A brake pad according to claim 1, characterized in that, The support base is 3-5mm thick, made of Q235 carbon structural steel, and has a copper plating thickness of 3-10μm.

6. A brake pad according to claim 1, characterized in that, The solder particle size is 500-600 mesh.

7. A method for preparing a brake pad as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1): Weigh the matrix component, the matrix reinforcing component and the friction component according to the formula and mix them evenly to obtain a mixture; Step 2), mix the lubricating component of the formula with the mixture obtained in step 1) evenly to obtain the friction material; Step 3): Weigh the low-density metal powder and the copper powder according to the formula and mix them evenly to obtain the solder; Step 4): Place the support base in the mold, lay 0.5-1.5mm of the solder on top of the support base, lay 15-25mm of the friction material on top of the solder, and press it into a blank under a pressure of 10-16MPa. Step 5) Sinter the pressed blank obtained in step 4) Apply 3.5-7.5KN above the friction material and obtain brake pads after cooling.

8. The method for preparing a brake pad according to claim 7, characterized in that, In step 5), during the sintering process, the protective gas is 15-25% hydrogen and 75-85% inert gas, the heating rate is 15-25℃ / min, and the temperature is raised to 400℃, 500℃, 600℃ and 700℃ in stages, and then held for 10-20 min respectively. The sintering temperature is 750-850℃ and the holding time is 1-3 h.

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