CN110360254B - Friction particles for friction material, preparation method of friction particles and high-porosity light-weight drum brake pad prepared from friction particles - Google Patents

Abstract

The invention relates to a brake pad, in particular to friction particles for a friction material, a preparation method of the friction particles and a high-porosity light-weight drum brake pad prepared by the friction particles. A friction particle for a friction material is prepared from the following raw materials in parts by weight: 4-8 parts of butyronitrile latex, 3-6 parts of 1220 resin, 6-10 parts of graphite, 2-4 parts of secondary high-temperature adhesive, 4-8 parts of calcium sulfate whisker and 50 parts of filler. The filler is generally made of cheap raw materials and is filled into the formula to reduce the cost. The invention fully utilizes the physical characteristics of each material of the brake pad, increases the porosity of the product and reduces the specific gravity of the product, thereby not only ensuring the stable performance of the brake pad, but also reducing the brake noise and increasing the brake comfort, and also meeting the development trend of light weight of automobiles and reducing the production cost.

Description

Friction particles for friction material, preparation method of friction particles and high-porosity light-weight drum brake pad prepared from friction particles

Technical Field

The invention relates to a brake pad, in particular to friction particles for a friction material, a preparation method of the friction particles and a high-porosity light-weight drum brake pad prepared by the friction particles, and belongs to the technical field of automobile parts.

Background

According to the development trend of light weight of automobiles, the traditional automobiles abroad are leading greatly, and China is accelerating to catch up. The development of lightweight brake pads serving as one of automobile parts is a necessary trend, and the brake pads on the market are generally high in density (not less than 2.1 g/cm)³) The porosity is low (less than 10%). Therefore, the weight of the brake pad is large, and the development of light weight of an automobile is not facilitated. The current research and development direction is to reduce the generation of brake noise and increase the comfort level of automobile braking.

Disclosure of Invention

The invention aims to provide friction particles for a friction material, which are added into the friction material, so that the porosity among the friction materials is increased, dust in the production process can be reduced, and the purpose of increasing the porosity and reducing the weight of a brake pad product is achieved.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a friction particle for a friction material is prepared from the following raw materials in parts by weight: 4-8 parts of butyronitrile latex, 3-6 parts of 1220 resin, 6-10 parts of graphite, 2-4 parts of secondary high-temperature adhesive, 4-8 parts of calcium sulfate whisker and 50 parts of filler. The filler is generally made of cheap raw materials and is filled into the formula to reduce the cost.

Preferably, the particle diameter of the friction particles is not more than 2.00 mm. A more preferable range is 1.7 to 2.4 mm.

Preferably, the filler is selected from one or a combination of several of barium sulfate, rubber powder, magnesium hydroxide, reinforcing fiber and milled powder.

Preferably, the formula of the filler in parts by weight is as follows: 20-22 parts of barium sulfate, 3-4 parts of rubber powder, 4-6 parts of magnesium hydroxide, 15-18 parts of reinforcing fiber and 6-7 parts of ground powder.

The preparation method of the friction particles for the friction material adopts an internal mixer for rubber to carry out modified infiltration granulation on raw materials to prepare the friction particles, and comprises the following specific processes: sequentially adding graphite and a secondary high-temperature adhesive in the raw materials, then adding a filler, finally adding butyronitrile latex and 1220 resin, refining in an internal mixer at the temperature of 105-115 ℃ for 15-20 minutes to fully combine the butyronitrile latex and the resin, finally discharging to form loose granules, adding calcium sulfate whiskers into the granules before discharging, and mixing to obtain the friction granules. Calcium sulfate whiskers are added into the granular materials before discharging so as to ensure that the shapes of whisker fibers are kept under the condition that the calcium sulfate whiskers are adhered to the granular materials.

A friction material is prepared from the following raw materials in parts by weight: 9-15 parts of phenolic resin, 5-8 parts of barium sulfate, 7 parts of friction powder, 3-5 parts of magnesium hydroxide, 5-12 parts of 6-40 mesh particle graphite, 6-10 parts of 10-20 mesh particle flexible coke powder, 10-20 parts of reinforcing fiber, 1-4 parts of wood fiber, 3-8 parts of calcium sulfate whisker, 0.5-2 parts of secondary high-temperature adhesive, 30-50 parts of friction particle as claimed in claim 1, 3-8 parts of foamed iron powder and 5-10 parts of glass fiber. The secondary high temperature adhesive of the present invention is generally foamed alumina. The glass fiber is alkali-free glass fiber with the thickness of 3-6 mm.

The high-porosity light-weight drum brake pad is prepared from the friction material.

The preparation method of the high-porosity light-weight drum brake pad comprises the following steps:

a. a material mixing procedure, wherein the raw materials are mixed according to a proportion, the mixing time is 900 +/-10 seconds, and the material mixing temperature is controlled below 50 ℃;

b. a hot-press molding step, wherein the friction material is subjected to electromagnetic hot-press molding and one-step cylinder mold molding, the pressure is 2.5 MPa, the pressing time is 90 +/-5 seconds/mm, the hot-press temperature is 160-170 ℃, and the temperature fluctuation is controlled within +/-2 ℃;

c. a heat treatment process, wherein the equipment adopts an automatic temperature control heat treatment box, the temperature is raised from room temperature to 130 +/-5 ℃ for 1 hour, the temperature is kept constant at 130 +/-5 ℃ for 1 hour, the temperature is raised for 2 hours at 130-170 ℃, the temperature is kept constant at 170 +/-5 ℃ for 7 hours, and the time fluctuation is controlled within +/-10 min;

d. the inner arc grinding process is completed by adopting a combined grinder, and the inner arc, the chamfer and the edge cutting are completed at one time;

e. a drilling process, wherein drilling is carried out by adopting an automatic numerical control technology drilling machine;

f. and (4) grinding the outer arc by adopting a disc cutting process.

The invention fully utilizes the physical characteristics of each material of the brake pad, increases the porosity of the product and reduces the specific gravity of the product, thereby not only ensuring the stable performance of the brake pad, but also reducing the brake noise and increasing the brake comfort, and also meeting the development trend of light weight of automobiles and reducing the production cost. According to the invention, through the selection of materials, raw materials with larger particles are selected, the porosity among the materials is increased, and alumina and iron powder treated by a high-temperature foaming technology are adopted.

Preferably, the material mixing process adopts a 3-step material mixing method, a plow-harrow type material mixer is used for mixing materials, four fly knives are arranged in the plow-harrow type material mixer, and the 3-step material mixing method comprises the following steps:

firstly, adding phenolic resin, barium sulfate, friction powder, granular flexible coke powder, magnesium hydroxide, granular graphite, secondary high-temperature adhesive and foamed iron powder into a fly cutter at the rotating speed of 2980 +/-10 revolutions per minute for mixing for 500 seconds in advance;

secondly, slowing down the fly cutter to 1400 +/-5 revolutions per minute, adding reinforcing fibers, wood fibers, calcium sulfate whiskers and friction particles, and mixing materials for 360 +/-10 seconds;

and thirdly, adding the glass fiber mixed material for 40 +/-5 seconds, and discharging.

Compared with the prior art, the invention has the beneficial effects that:

1) through the selection and treatment of materials, the specific gravity of the product can reach below 1.8 g/cm 3, the specific gravity is reduced by about 15 percent compared with the existing product, and the lightweight effect is obvious;

2) the material is subjected to a granulation technology, so that the granularity of the material is increased, the porosity among the materials is increased, the dust in the production process is greatly reduced, the aim of increasing the porosity and reducing the weight of the product is fulfilled, and the workshop production environment is improved;

3) the porosity of the product can reach 15 percent, which is about 50 percent higher than that of the traditional brake pad, thereby reducing the brake noise and increasing the brake comfort;

4) the increase of the porosity can effectively improve the heat dissipation speed after braking, reduce the braking temperature and prolong the service life of the product.

Detailed Description

The technical solution of the present invention will be further specifically described below by way of specific examples. It is to be understood that the practice of the invention is not limited to the following examples, and that any variations and/or modifications may be made thereto without departing from the scope of the invention.

In the present invention, all parts and percentages are by weight, unless otherwise specified, and the equipment and materials used are commercially available or commonly used in the art. The methods in the following examples are conventional in the art unless otherwise specified.

The raw material sources are as follows:

1220 resin, available from saint leikoku specialty chemicals (shanghai) ltd;

phenolic resin, 1252 resin, saint leikott chemistryage (shanghai) ltd;

secondary high temperature adhesives, available from beijing, gold composites, llc;

flexible coke powder, available from Changzhou Fengrun specialty fiber Co., Ltd;

wood fiber, available from Xinyi mineral Limited, yellow Stone;

foamed iron powder, available from beijing, gold composites, llc;

glass fiber, 3-6 mm alkali-free glass fiber, purchased from Jushi group GmbH of Tungxiang city;

reinforcing fibers, Jiangsu Ruiko materials, Inc.;

magnesium hydroxide, 320 mesh, hebei magical technologies ltd;

abrasive powder, type 2057, manufactured by kadela chemical (zhhai) limited.

Example 1:

a friction particle for a friction material is prepared by modifying, soaking and granulating raw materials by adopting an internal mixer for rubber, and comprises the following steps:

1. preparing raw materials: 4kg of butyronitrile latex, 6 kg of 1220 resin, 6 kg of graphite, 2kg of secondary high-temperature adhesive, 4kg of calcium carbonate whisker and 50kg of filler. The composition of 50kg of filler was: 20 kg of barium sulfate, 4kg of rubber powder, 4kg of magnesium hydroxide, 15 kg of reinforcing fiber and 7kg of ground powder. The grinding powder is dust generated in the grinding process when the brake pad is produced.

2. Sequentially adding graphite and a secondary high-temperature adhesive into an internal mixer, then adding a filler, finally adding butyronitrile latex and 1220 resin, refining for 15-20 minutes in the internal mixer at the temperature of 105-115 ℃, fully combining the butyronitrile latex and the resin, finally discharging to form loose granules, adding calcium sulfate whiskers into the granules before discharging, and mixing to obtain the friction particles. The particle size of the abrasive grains was controlled to 2.00mm or less (including 2.00 mm).

The friction particles prepared by the method are beneficial to increasing the porosity of the brake pad.

Example 2:

a high-porosity lightweight drum brake pad is prepared by the following method:

a. a material mixing procedure, wherein the raw materials are mixed in proportion, the mixing time is 900 seconds, and the material mixing temperature is controlled below 50 ℃;

the raw material ratio is as follows: 13kg of phenolic resin, 5kg of barium sulfate, 7kg of friction powder, 4kg of magnesium hydroxide, 5kg of 6-40-mesh granular graphite, 10kg of 10-20-mesh granular flexible coke powder, 15 kg of reinforcing fiber, 2kg of wood fiber, 8kg of calcium sulfate whisker, 2kg of foamed alumina, 30kg of friction particle (prepared in example 1), 3kg of foamed iron powder and 5kg of glass fiber.

The material mixing process adopts a 3-step material mixing method, a plow-harrow type material mixer is used for mixing materials, four fly knives are arranged in the plow-harrow type material mixer, and the 3-step material mixing method comprises the following steps:

firstly, adding phenolic resin, barium sulfate, friction powder, granular flexible coke powder, magnesium hydroxide, granular graphite, foamed aluminum oxide and foamed iron powder into a fly cutter at the rotating speed of 2980 +/-10 revolutions per minute for mixing for 500 seconds in advance;

secondly, slowing down the fly cutter to 1400 +/-5 revolutions per minute, adding reinforcing fibers, wood fibers, calcium sulfate whiskers and friction particles, and mixing materials for 360 +/-10 seconds;

and thirdly, adding the glass fiber mixed material for 40 +/-5 seconds, and discharging.

b. A hot-press molding step, wherein the friction material is subjected to electromagnetic hot-press molding and one-step cylinder mold molding, the pressure is 2.5 MPa, the pressing time is 90 +/-5 seconds/mm, the hot-press temperature is 160-170 ℃, and the temperature fluctuation is controlled within +/-2 ℃;

c. a heat treatment process, wherein the equipment adopts an automatic temperature control heat treatment box, the temperature is raised from room temperature to 130 +/-5 ℃ for 1 hour, the temperature is kept constant at 130 +/-5 ℃ for 1 hour, the temperature is raised for 2 hours at 130-170 ℃, the temperature is kept constant at 170 +/-5 ℃ for 7 hours, and the time fluctuation is controlled within +/-10 min;

d. the inner arc grinding process is completed by adopting a combined grinder, and the inner arc, the chamfer and the edge cutting are completed at one time;

e. a drilling process, wherein drilling is carried out by adopting an automatic numerical control technology drilling machine;

f. and grinding the outer arc, and manufacturing a brake pad product by adopting a disc cutting process.

The quality of the brake pad product prepared by the embodiment is detected by sampling, and the data is as follows:

firstly, constant speed testing:

temperature of

100℃

150℃

200℃

250℃

300℃

350℃

Coefficient of friction at elevated temperature

0.38±0.05

0.38±0.07

0.38±0.08

0.38±0.08

0.38±0.10

0.38±0.10

Coefficient of friction at reduced temperature

0.38±0.05

0.38±0.07

0.38±0.08

0.38±0.08

0.38±0.10

Wear rate

≤0.15

≤0.3

≤0.40

≤0.50

≤0.80

≤1.00

Second, impact strength

The impact strength is more than or equal to 0.32J/cm²

Thirdly, the specific gravity of the product is less than or equal to 1.8 g/cm³

Fourthly, the porosity of the product reaches more than 15 percent.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.

Claims (1)

1. A high-porosity lightweight drum brake pad is characterized in that the brake pad is prepared by the following method:

a. a material mixing procedure, wherein the raw materials are mixed in proportion, the mixing time is 900 seconds, and the material mixing temperature is controlled below 50 ℃;

the raw material ratio is as follows: 13kg of phenolic resin, 5kg of barium sulfate, 7kg of friction powder, 4kg of magnesium hydroxide, 5kg of 6-40-mesh granular graphite, 10kg of 10-20-mesh granular flexible coke powder, 15 kg of reinforcing fiber, 2kg of wood fiber, 8kg of calcium sulfate whisker, 2kg of foamed alumina, 30kg of friction particle, 3kg of foamed iron powder and 5kg of glass fiber;

the friction particles for the friction material are prepared by adopting an internal mixer for rubber to carry out modified infiltration granulation on raw materials, and the method comprises the following steps:

1. preparing raw materials: 4kg of butyronitrile latex, 6 kg of 1220 resin, 6 kg of graphite, 2kg of secondary high-temperature adhesive, 4kg of calcium carbonate whisker and 50kg of filler; the composition of 50kg of filler was: 20 kg of barium sulfate, 4kg of rubber powder, 4kg of magnesium hydroxide, 15 kg of reinforcing fiber and 7kg of ground powder; the grinding powder is dust generated in the grinding process when the brake pad is produced;

2. sequentially adding graphite and a secondary high-temperature adhesive into an internal mixer, then adding a filler, finally adding butyronitrile latex and 1220 resin, refining for 15-20 minutes in the internal mixer at the temperature of 105-115 ℃, fully combining the butyronitrile latex and the resin, finally discharging to form loose granules, adding calcium sulfate whiskers into the granules before discharging, and mixing to obtain friction particles; the particle size of the friction particles is controlled to be less than 2.00 mm;

the material mixing process adopts a 3-step material mixing method, a plow-harrow type material mixer is used for mixing materials, four fly knives are arranged in the plow-harrow type material mixer, and the 3-step material mixing method comprises the following steps:

firstly, adding phenolic resin, barium sulfate, friction powder, granular flexible coke powder, magnesium hydroxide, granular graphite, foamed aluminum oxide and foamed iron powder into a fly cutter at the rotating speed of 2980 +/-10 revolutions per minute for mixing for 500 seconds in advance;

secondly, slowing down the fly cutter to 1400 +/-5 revolutions per minute, adding reinforcing fibers, wood fibers, calcium sulfate whiskers and friction particles, and mixing materials for 360 +/-10 seconds;

thirdly, adding the glass fiber mixed material for 40 +/-5 seconds, and discharging;

b. a hot-press molding step, wherein the friction material is subjected to electromagnetic hot-press molding and one-step cylinder mold molding, the pressure is 2.5 MPa, the pressing time is 90 +/-5 seconds/mm, the hot-press temperature is 160-170 ℃, and the temperature fluctuation is controlled within +/-2 ℃;

c. a heat treatment process, wherein the equipment adopts an automatic temperature control heat treatment box, the temperature is raised from room temperature to 130 +/-5 ℃ for 1 hour, the temperature is kept constant at 130 +/-5 ℃ for 1 hour, the temperature is raised for 2 hours at 130-170 ℃, the temperature is kept constant at 170 +/-5 ℃ for 7 hours, and the time fluctuation is controlled within +/-10 min;

d. the inner arc grinding process is completed by adopting a combined grinder, and the inner arc, the chamfer and the edge cutting are completed at one time;

e. a drilling process, wherein drilling is carried out by adopting an automatic numerical control technology drilling machine;

f. and grinding the outer arc, and manufacturing a brake pad product by adopting a disc cutting process.