JPS61106687A - Frictional material for vehicle - Google Patents

Abstract

PURPOSE:A frictional material for a vehicle such as a wet friction clutch excellent in heat resistance, frictional characteristics and wear resistance, constituted of a substrate primarity consisting of a fiber, a friction modifier and a binder made of an inorg. material for binding the both. CONSTITUTION:10-60pts. (by wt. based on 100pts. of the total of a frictional material to be prepd. the same applies hereinafter) of a substrate (A) constituting the primary component of the frictional material to be obtd. and comprising an inorg. fiber such as rock wool, an org. fiber such as an aramid fiber excellent in heat resistance or a mixture thereof and 30-50pts. of a friction modifier (B) such as an inorg. powder, e.g. diatom earth, an org. powder,e.g. cashew dust or a metal powder, e.g. an Al powder are added to water, and then disintegrated, dispersed and made into a sheet. The sheet is impregnated with a liquid binder made of an inorg. material of thermal decomposition temp. >=260 deg.C primary consisting of colloidal silica, etc. and heated at 60-100 deg.C, then at 150-200 deg.C. The components (A) and (B) are bound with the binder which is set and molded into a predetermined form by a press, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a II friction material used in vehicles such as automobiles. INDUSTRIAL APPLICABILITY The present invention can be used, for example, in a wet friction clutch for cutting off power transmission, which is used while immersed in oil in a vehicle transmission.

[Prior Art] This ear friction material for vehicles is required to have good performance such as good S hospitality, heat resistance, and abrasion resistance. Therefore, traditionally,
GW materials for vehicles are 11 for vehicles from inorganic materials and organic materials! It is constructed by appropriately selecting a base material depending on the type of friction material, adding a friction modifier as appropriate to this base material, and bonding with a thermosetting resin such as a phenolic resin. .

For example, the friction material for vehicles disclosed in Japanese Patent Publication No. 46-21123 is made by integrating a felt-like sheet adsorbed with organic activated carbon and a phenolic resin, and molding the resultant under heat and pressure.

Furthermore, the friction material for vehicles disclosed in Japanese Patent Publication No. 48-24101 is as follows:
It is made by heating wood pulp and thermosetting resin without applying pressure and then molding them under hot pressure.

Also, 11 for vehicles of Japanese Patent Application Laid-open No. 57-200477
The friction material is made by blending inorganic fibers and heat-resistant organic fibers with pulp particles made of magnesium oxide, 2□1 ram of magnesium hydroxide, and an aromatic polymer, impregnating it with a thermosetting resin, and applying heat pressure. It is molded.

Furthermore, the friction material for vehicles disclosed in Japanese Patent Application Laid-Open No. 58-191339 is as follows:
It is made by combining a mixture of rock wool and cellulose fibers with phenolic resin and molding them under heat and pressure.

The reason why thermosetting resins such as phenolic resins are used in the conventional friction materials for vehicles described above is because they meet the conditions such as friction characteristics, heat resistance, and wear resistance.

The conventional friction materials for vehicles described above almost satisfy the heat resistance required for automotive parts at the current stage.

[Problems to be Solved by the Invention] With regard to JL friction materials used in automobiles, there is a strong demand for a vehicle friction material with better heat resistance as engine performance has improved in recent years.

In addition, in recent years, there has been a strong demand for lighter weight in automobile parts, and there is a need to reduce the weight of transmissions by reducing the number of friction materials used in vehicles, which are components of transmissions. There is a strong demand for friction materials for automobiles to ensure a predetermined heat resistance with a smaller number of sheets.

In view of the above-mentioned circumstances, in recent years, in order to improve the heat resistance of friction materials for vehicles, efforts have been made to improve the heat resistance of the base material itself, which is the main component of *m materials for vehicles. There is. For example, a friction material for vehicles has been developed in which the base material is made of aramid fibers and the thermal decomposition temperature of the base material is increased to 400 to 600°C.

However, in the conventional technology described above, the thermosetting resin that binds the base material and the friction modifier is an organic resin, and the thermal decomposition temperature is about 260° C. at most. Therefore, there is a limit to improving the heat resistance of friction materials for vehicles by simply improving the heat resistance of the base material itself.

The present invention is intended to solve the above-mentioned problems, and its object is to provide a friction material for vehicles that has further improved heat resistance.

[Means for Solving the Problems] The present invention uses a binder made of an inorganic material whose thermal decomposition temperature is higher than that of a thermosetting resin. That is, the friction material for vehicles of the present invention is characterized in that it is composed of a base material mainly composed of fibers, an abrasive WAwA modifier, and a binder made of an inorganic material that binds the base material and the friction modifier. That is.

Here, the friction material for vehicles refers to a material that primarily slides on a metal counterpart and converts kinetic energy into thermal energy through the sliding friction. A typical example of the vehicular fiber material is a wet friction clutch used in an automobile transmission, and in some cases, a brake lining, a brake pad, etc. used in an automobile brake mechanism may be used.

The base material, which is a component of the present invention, constitutes the main body of the friction material for a vehicle. The base material can be composed of inorganic fibers, organic fibers with excellent heat resistance, or a mixture of both. As inorganic fibers, glass fiber,
One or more of ceramics 1I11, silica fibers, alumina fibers, rock wool, and metal fibers can be used. Rock wool, also known as rock wool, is an amorphous artificial inorganic fiber made by melting several types of ore using light and heat and blowing it away using centrifugal force or compressed air into a thin msi-like shape. As an organic fiber, 1 liter has heat resistance.
II is desirable, and for example, one or more of aramid fibers, carbon fibers, and phenol I1M can be used. The blending ratio of the base material is appropriately selected depending on the type of friction material for a vehicle. When the entire vibration material for vehicles is 100 parts by weight, the proportion of the base material can be 10 to 60 parts by weight.

The other component of the present invention is M*! l! The first agent is one that increases the friction coefficient of the R11 friction material for vehicles by: lIM. When a vehicle friction material is used in oil, the friction coefficient of the vehicle friction material is likely to be insufficient, so a friction modifier may be added to improve the friction coefficient of the vehicle friction material. The friction modifiers are conventional, 1. °゛″1°'
81i18(+)6f)tm°' 8 Z k $'
C' e 6゜ That is, as a friction modifier, S machine powder,
Organic powders and metal powders can be used as appropriate. For example, barium sulfate, diatomaceous earth, alumina, dolomite, calcium carbonate, calcium hydroxide, graphite, carbon black, kynor, cashew dust, rubber dust, aluminum, iron, zinc, etc. are used depending on the type of friction material for vehicles. used.

The blending ratio of the friction modifier is appropriately selected depending on the type of friction material for a vehicle. When the entire friction material for vehicles is 100 parts by weight, friction! The proportion of the 111m agent can be 30 to 50 parts.

The binding agent, which is a defining component of the invention, is made from an inorganic material. Here, as the binder, a binder whose main components are colloidal silica, colloidal alumina, colloidal iron hydroxide, colloidal titania, and colloidal zirconia is usually used, but in some cases, phosphate,
A binder containing an alkali metal silicate or an alkyl silicate as a main component may also be used. This binder is for vehicle
11 requested as a vibration material! The selection should take into account various properties such as friction coefficient, abrasion resistance, heat resistance, and water resistance.If the friction material for vehicles is a wet friction material, water resistance is particularly required since it will be used in oil. No. One type of binder may be used, or two or more types may be mixed as necessary to satisfy the above properties. Phosphate generally exhibits acidity. Therefore, there is a need to be careful.

The colloidal silica before bonding here is made by dispersing 3ioz fine particles with a diameter of generally 5 to 10O1μ in water or alcohol, and adding a stabilizer such as Nata. Before bonding, colloidal silica has fine particles dispersed in water or alcohol, so it easily penetrates into fine gaps, and when dried and heated, it hardens by detachment of bound water and dehydration condensation of silanol groups on the surface of 5iot fine particles. Since this colloidal silica mainly consists of fine particles, the contact area becomes larger and the bonding strength becomes larger.

The various binders mentioned above have high adhesive strength (and thermal decomposition temperature is usually 260°C or higher, which is higher heat resistance than organic resins.) It may contain agents, curing agents, aggregates, etc. as necessary.

The blending ratio of the binder is appropriately selected depending on the type of vehicle II vibration material, but in general, it is preferably about 10 to 35 parts by weight when the total amount is 100 parts by weight.

The main reason for this is that if the amount is less than 10 parts by weight, sufficient binding force between the fibers of the base material cannot be secured, and if it is more than 35 parts by weight, the pores will be clogged, making it difficult to secure the desired porosity. This is because it becomes difficult.

Now, a typical manufacturing method of the vehicle friction material of the present invention will be described. First, the base material, friction modifier, and water are mixed and beaten.
Distribute. Next, paper is made using a Fourdrinier type or circular wire type paper machine. Thereafter, it is impregnated with a liquid binder containing colloidal silica or the like as a main component, and heated at 60 to 100°C. The reason for heating at 60 to 100°C is mainly to evaporate water. 150℃~20℃ for reception
Heat at 0°C. As a result, the binder in a liquid state is cured, and the base material and the friction modifier are bonded by the binder.

The heating is usually carried out by successive passage through two furnaces. After heating, it is molded into a predetermined shape at a temperature of 150 to 200°C. The above-described molding is usually performed using a heated press. Alternatively, it can also be performed using a crimping jig. For press-molded products, it is also preferable to heat the molded product at 170 to 200° C. for 10 to 20 minutes to completely cure the binder.

Effect of ER Light] As the binder for binding the rlJ friction vibration material for vehicles of the present invention, the base material, and the friction modifier, a binder made of an inorganic material is used. The thermal decomposition temperature of this inorganic binder is higher than that of thermosetting resins used as binders in conventional friction materials for vehicles.

Therefore, the heat resistance of the friction material for vehicles of the present invention can be improved accordingly.

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A summary of each example is shown in Table 1.

(Example 1) Heat-resistant fibers such as rockwool, aramid fiber, and glass fiber were used as the base material, and the proportions were as follows:
As shown in the table, they were respectively 20%, 30%, and 40% (% indicates wt%). Furthermore, diatomaceous earth was used as a friction modifier, and its proportion was 10%. The binder made of an inorganic material was Colloidal Sili "1-Riki", which was 8-130F (particle size: 8 mμ) manufactured by Shinsho Kagakusha Co., Ltd., and its proportion was 10%.

Then, the base material and the S* modifier were mixed with water, beaten and dispersed, and then paper was made using a circular mesh paper machine. Thereafter, the binder in a liquid state was impregnated, and the water was evaporated by heating and holding at 70° C. for 10 minutes.

Thereafter, precure was performed at 160'C for 40 minutes.

Pre-curing specifically involves curing the binder by passing the impregnated material through an oven. Thereafter, it was molded into a predetermined shape at 113F and 170° C., a molding pressure of 100 kQ/fiber 2, and a molding time of 2 minutes, and the binder was applied to a predetermined thickness to form the vehicle friction material of Example 1. Specifically, the molding was performed using a heated press.

(Example 2) Rock wool and aramid fiber were used as the base material, and the respective proportions were 40% and 20% as shown in Table 1. Furthermore, cashew dust and diatomaceous earth were used as friction modifiers, and the respective proportions were 20% and 20%. The binder made of an inorganic material is colloidal silica, and S-120A (particle size IEIμ) manufactured by Shinsho Kagakusha is used, and its proportion is 25%. Vehicle IL of Example 2! The friction material vibration material manufacturing process was the same as in Example 1 except that the precure temperature was 200°C.

(Example 3) Rock wool, aramid fiber, and glass fiber were used as the base material, and the respective proportions were 50%, 15%, and 1 as shown in Table 1.
It was set to 0%. Also, cashew dust and diatomaceous earth were used as a polishing agent, and the respective proportions were 15% and 10%.

The binder made of inorganic material is colloidal silica, and S-150 (particle size 25n+μ) manufactured by Shinsho Kagakusha is used.
The percentage is 35%. In the case of Example 3, the ratio of the binder is 35%, which is higher than in Examples 1 and 2. The reason is that the particle size of the silica is large, so the adhesive area between the silica and the base material is increased. This is to do so. In the manufacturing process of the vehicle friction material of Example 3, the pre-cure temperature was 200"
This is the same as in Example 1 except that C.

<Comparative Example> A comparative example of a friction material for vehicles (a conventionally available material) using a thermosetting resin as the binder was also formed. In the vehicle friction material of the comparative example, link valves and rock wool were used as base materials, and the proportions were 30% and 40% as shown in Table 1. Also, diatomaceous earth was used as a f*Xll conditioner, and the proportion was 30%. The binder was a phenolic resin as a thermosetting resin, and the proportion was 30%. The manufacturing process of the vehicle friction material of the comparative example is basically the same as that of the first example.

(Evaluation) The coefficient of dynamic friction, wear pot, and heat resistance were measured for the vehicle friction materials of Examples 1 to 3 and the vehicle friction materials of Comparative Examples. This measurement was performed using the SAE #2 test machine (a test machine developed by the Friction Subcommittee of the American Society of Automotive Engineers).
It was held at SA”IE #2 atti
cyo□94□□692.7iyo The test clutch absorbs the kinetic energy of rotating objects, including the eel, and analyzes the performance and durability of the test clutch based on the degree of absorption and durability. The energy is changed by changing the capacity or rotational speed of the flywheel.

The test results are shown in Figure 1 and Table 2. As shown in Figure 1, in the comparative example -30ca per square centimeter.
When l, the number of durability cycles is 15000oo,
- 1 when 5Qca I per square centimeter
The number of durable cycles was 50ooo. On the other hand, in Examples 1 to 3, 45 per square centimeter
The number of durable cycles was 150 oOoo when the cal was used, and the number of durable cycles was 1500 when the cal was 75 cal per square centimeter. From this, it can be seen that Examples 1 to 3 withstood a heat load about 1.4 times that of the comparative example and had excellent heat resistance.

Oh, ! ″ff11!ff1fi12Xl'l＆!ji
1'ff1k: 2°゛1'"・126; As shown in □, it is almost the same as the comparative example. From this, Example 1
It can be seen from Table 2 that in Example 3, the excellent II abrasion resistance and abrasion resistance of the comparative example can be maintained. That is, the vehicle friction materials of Examples 1 to 3 can improve heat resistance without impairing the friction characteristics and wear resistance of conventional vehicle friction materials.

[Brief explanation of the drawing]

FIG. 1 is a graph for evaluating the heat resistance of Examples and Comparative Examples.

Claims (9)

[Claims] (1) A friction material for a vehicle comprising a base material mainly composed of fibers, a friction modifier, and a binder made of an inorganic material that binds the base material and the friction modifier. (2) The friction material for a vehicle according to claim 1, wherein the binder is impregnated between the base material and the friction modifier after paper making. (3) The friction for a vehicle according to claim 1, wherein the binder is a binder whose main components are colloidal silica, colloidal alumina, colloidal titania, colloidal zirconia, phosphate, alkali metal silicate, and alkyl silicate. Material. (4) The friction material for a vehicle according to claim 1, wherein the thermal decomposition temperature of the binder is 260° C. or higher. (5) The friction material for a vehicle according to claim 1, wherein the proportion of the binder is 10 to 35 parts by weight when the total amount is 100 parts by weight. (6) The friction material for a vehicle according to claim 1, wherein the base material is composed of inorganic fibers, organic fibers with excellent heat resistance, or a mixture of both. (7) Inorganic fibers include glass fiber, ceramic fiber,
The friction material for a vehicle according to claim 6, which is one or more of silica fiber, alumina fiber, rock wool, and metal fiber. (8) The friction material for a vehicle according to claim 6, wherein the organic fiber is one or more of aramid fiber, carbon fiber, and phenol fiber. (9) The vehicle friction material according to claim 1 is a wet friction clutch.