CN102364144B - Application of rice husks in preparation of brake pad, and friction material for brake pad - Google Patents

Abstract

The invention discloses application of rice husks in preparation of a brake pad, and a friction material for preparing the brake pad. The brake pad is prepared by the following materials in percentage by weight according to a conventional brake pad pressing method: 10 to 15 percent of mineral fiber, 5 to 10 percent of graphite, 15 to 25 percent of barium sulfate, 15 to 20 percent of steel wool, 1 to 3 percent of friction enhancement agent, 3 to 15 percent of coke dust, 1 to 4 percent of tire powder, 7 to 11 percent of resin, 1 to 3 percent of butyl powder, 1 to 2 percent of calcium oxide and 5 to 30 percent of rice husk. In the friction material, the rice husks are used as a friction filling; and the brake pad made of the friction filling and other raw materials by using the conventional brake pad pressing method is subjected to a four-class test on a fixed speed experiment according to the standard GB5763-2008; the friction coefficient is stable, the wear rate is low, and the national standard can be met. The brake pad used in Santana, sonata and jetta taxies is stable in breaking and noise-free; and a vehicle with the brake pad can run as long as 35,000 kilometers or more.

Description

Application of rice husk in the preparation of brake pads and a friction material for brake pads

technical field

The present invention relates to a new application of rice husk, especially in the preparation of brake pads, and a brake pad friction material containing rice husks.

Background technique

The most important safety system on a car is the braking system, and all braking components are safety components. Brake pads are one of the most important links in the entire braking system, which will directly affect the reliability of the entire braking system.  Brake pads and brake discs (or brake drums) rub against each other to form a frictional couple, generate braking torque, and convert the kinetic energy of the car into heat energy. When braking, the temperature of the brake pads and brake discs will rise by 300-400°C. Brakes Brake pads and discs (or drums) are the most stressed components in a vehicle, subject to extreme heat, mechanical and chemical stress. .In addition, brake pads are exposed to external environmental influences such as moisture, dust and stains for a long time, which will affect their performance and life.

The dynamic friction coefficient of the brake pad determines the magnitude of the braking force, and the friction coefficient also plays a decisive role in the braking balance and the stability of the vehicle operation during braking. A reduction in the coefficient of friction can cause a considerable change in braking performance, possibly resulting in a substantial increase in stopping distance, posing a threat to personal safety. The coefficient of friction of the brake pad must therefore be stable under all driving conditions (speed, temperature, humidity, pressure) and throughout its service life. For a good brake pad, the coefficient of friction must meet the braking requirements and remain stable under various driving conditions.

Brake pads generally consist of a steel back, an adhesive layer and a friction layer. The friction materials that make up the friction layer include materials such as adhesives, fibers, fillers, friction enhancers, and friction reducers. Depending on the model, it is sometimes necessary to add shock-absorbing gaskets, brushing glue, slotting, grinding bevels and other processes in order to increase the performance of the braking system.

Because brake pads are prone to brake noise during the braking process, the use of fillers in friction materials must consider the noise reduction function. The widely used noise reduction fillers on the market include expansive materials such as expanded vermiculite and expanded perlite. , Most of these materials are minerals that are refined and processed, and the dust in the processing process is very large, which seriously pollutes the environment. Granular materials, such as granular graphite, are processed and synthesized after mineral extraction, which consumes a lot of energy and dust during the manufacturing process, which can easily cause respiratory diseases for operators.

Rice husk is the outer layer of rice grains, which can be used to make soy sauce, wine, and fuel. The composition of rice husk is also different due to different places of production. Its basic chemical composition is: moisture accounts for 7.5% to 15%, crude fiber accounts for 35.5% to 45%, lignin accounts for 21% to 26%, and crude protein accounts for 2.5% to 3.0%. %, lipids account for 0.7% to 1.3%, pentosan accounts for 16% to 22%, and ash accounts for 13% to 22%.

Rice is one of the crops with the widest planting area and the largest yield in the world. The world produces more than 600 million tons of rice every year. After the rice is processed into rice, most of the rice husks are discarded as waste or used as low-grade fuel, and farmers in many places burn the rice husks and straw together. When burning, a large amount of carbon dioxide is directly discharged into the atmosphere, and a large amount of dust is generated. The dense smoke generated during burning can also cause respiratory diseases. The above-mentioned treatment methods not only pollute the environment, but also cause a waste of resources.

Contents of the invention

The purpose of the present invention is to provide a new application of rice husk in the preparation of brake pads. Due to the characteristics of the rice husk itself, it has large porosity, high content of ash (the chemical composition of this ash is mainly silica) and rich fibers, the surface area is large, and it has good noise reduction performance. It is very suitable as a brake pad. friction filler. The rice husk is used as a filler to prepare brake pads, which can effectively absorb braking noise and reduce noise pollution during the braking process of the brake pads while ensuring the friction coefficient and service life.

The present invention also provides a friction material for preparing brake pads, which is characterized in that it is prepared from the following materials in parts by weight according to a conventional brake pad pressing method: 10-15% of mineral fiber, 5-10% of graphite, sulfuric acid Barium 15-25%, steel wool 15-20%, grinding agent 1-3%, coke powder 3-15%, tire powder 1-4%, resin 7-11%, nitrile powder 1-3%, oxidation Calcium 1-2%, rice husk 5-30%. the

Further, the friction material used to prepare the brake pads is preferably prepared from the following materials in parts by weight according to the conventional brake pad pressing method: 15% mineral fiber, 10% graphite, 25% barium sulfate, 17% steel wool, abrasive enhancer 2%, coke powder 10%, tire powder 2%, resin 7%, nitrile powder 1%, calcium oxide 1%, rice husk 10%.

Furthermore, the grinding agent can be chromite powder, aluminum oxide or zirconium oxide, etc., which increase the coefficient of friction.

In the present invention, the rice husk raw material can be processed physically or chemically, or can be directly used as a brake pad friction filler and pressed together with other components to form a brake pad without processing.

Rice husk has high porosity, low density (bulk density less than 20g/100ml), high strength and good wear resistance. Using rice husks to prepare brake pads can reduce the weight of brake pads, thereby reducing the weight of automobiles and playing a certain role in energy saving of automobiles.

The friction material of the present invention uses rice husk as the friction filler, and together with other raw materials, the brake pad is prepared by the conventional brake pad pressing method. According to the GB5763-2008 standard in the constant speed test, the friction coefficient is stable and the wear rate is small. , fully meet the national standard. It has been widely used in Santana, Sonata and Jetta taxis, with smooth braking, no noise complaints, and a service life of more than 35,000 kilometers.

The market supply of rice husk is large, the raw material is easy to obtain, and the price is cheap. As a friction filler for brake pad friction materials, the market application prospect is very broad.

In the present invention, the new use of rice husks in the preparation of brake pads can not only reduce pollution and purify the environment, but also can fully utilize waste, and can also recycle resources and energy to create economic benefits, which is in line with national energy conservation and emission reduction, and waste recycling The basic national policy of utilization and sustainable development.

Conventional brake pad pressing methods are not particularly limited, as long as the components are mixed evenly, and the conditions and equipment for mixing, pressing and heat treatment are well known to those skilled in the art. For example: pressing temperature: 160°C; pressure: 400MPa; time: 1min/mm under the condition of one-time pressing. Heat treatment process: heat preservation at 170°C for 2 hours, heat preservation at 190°C for 3 hours.

Detailed ways

Example 1:

Mineral fiber 15%, graphite 10%, barium sulfate 25%, steel wool 17%, grinding agent 2%, coke powder 15%, tire powder 2%, resin 7%, nitrile powder 1%, calcium oxide 1%, Rice husk 5%, total 100%.

The above-mentioned materials were made into brake pads according to the conventional pressing method, and tested according to category 4 on a constant speed testing machine according to the GB5763-2008 standard. The results are shown in Table 1.

Table 1:

It can be seen from the data in Table 1 that the brake pad obtained in Example 1 of the present invention has a friction coefficient of 0.35-0.41 in the heating stage, and a friction coefficient of 0.36-0.40 in the cooling stage, and the wear rate is small, which fully meets the national standard. After extensive use in Santana, Sonata and Jetta taxis, the braking is smooth, the braking noise is small, and the life of the friction material has reached more than 35,000 kilometers.

Example 2:

Mineral fiber 15%, graphite 10%, barium sulfate 25%, steel wool 17%, grinding agent 2%, coke powder 10%, tire powder 2%, resin 7%, nitrile powder 1%, calcium oxide 1%, Rice husk 10%, total 100%.

The above materials were made into brake pads according to the conventional pressing method, and tested according to category 4 on a constant speed testing machine according to the GB5763-2008 standard. The results are shown in Table 2.

Table 2:

It can be seen from the data in Table 2 that the brake pad obtained in Example 2 of the present invention has a friction coefficient of 0.34-0.42 in the heating stage, and a friction coefficient of 0.35-0.40 in the cooling stage, and the wear rate is small, which fully meets the national standard. After extensive use in Santana, Sonata and Jetta taxis, the braking is smooth, the braking noise is small, and the life of the friction material has reached more than 35,000 kilometers.

Example 3:

Mineral fiber 15%, graphite 10%, barium sulfate 20%, steel wool 15%, grinding agent 2%, coke powder 5%, tire powder 2%, resin 9%, nitrile powder 1%, calcium oxide 1%, Rice husk 20%, total 100%.

The above materials were made into brake pads according to the conventional pressing method, and tested according to category 4 on a constant speed testing machine according to the GB5763-2008 standard. The results are shown in Table 3.

table 3:

It can be seen from the data in Table 3 that the brake pad obtained in Example 3 of the present invention has a friction coefficient of 0.31-0.39 in the heating stage, and a friction coefficient of 0.34-0.37 in the cooling stage, and the wear rate is small, which fully meets the national standard. After extensive use in Santana, Sonata and Jetta taxis, the braking is smooth, the braking noise is small, and the life of the friction material has reached more than 35,000 kilometers.

Example 4:

Mineral fiber 10%, graphite 5%, barium sulfate 15%, steel wool 20%, grinding agent 2%, coke powder 3%, tire powder 2%, resin 11%, nitrile powder 1%, calcium oxide 1%, Rice husk 30%, total 100%.

The above materials are made into brake pads according to the conventional pressing method, and tested according to category 4 on a constant speed testing machine according to the GB5763-2008 standard. The results are shown in Table 4.

Table 4:

It can be seen from the data in Table 4 that the brake pad obtained in Example 4 of the present invention has a friction coefficient of 0.34-0.40 in the heating stage and a friction coefficient of 0.34-0.36 in the cooling stage, and the wear rate is small, which fully meets the national standard. After extensive use in Santana, Sonata and Jetta taxis, the braking is smooth, the braking noise is small, and the life of the friction material has reached more than 35,000 kilometers.

Claims (3)

1. a friction material that is used to prepare brake block is characterized in that, is prepared from by conventional brake block drawing method following materials in weight portion: mineral fibre 10 ~ 15%, graphite 5-10%; Barium sulphate 15-25%, steel wool 15-20% increases grinding agent 1-3%; Coke powder 3-15%, tyre talc 1-4%, resin 7-11%; Butyronitrile powder 1-3%, calcium oxide 1-2%, rice husk 5-30%.

2. the friction material that is used to prepare brake block as claimed in claim 1 is characterized in that, is prepared from by conventional brake block drawing method following materials in weight portion: mineral fibre 15%, graphite 10%; Barium sulphate 25%, steel wool 17% increases grinding agent 2%; Coke powder 10%, tyre talc 2%, resin 7%; Butyronitrile powder 1%, calcium oxide 1%, rice husk 10%.

3. according to claim 1 or claim 2 the friction material that is used to prepare brake block is characterized in that the said grinding agent that increases is chromite powder, aluminium oxide or zirconium oxide.