JPS60200932A - Friction material - Google Patents

Abstract

PURPOSE:To provide a friction material which has a stable and high coefft. of friction and improved wear resistance by adding an adequate amt. of ferrochromium to a cupreous sintered metal formed by adding a lubricating component and metallic oxide to a matrix component consisting of copper, tin, zinc, etc. CONSTITUTION:A friction material is formed by incorporating 1-20% ferrochromium to a cupreous sintered alloy obtd. by adding a lubricating component such as about 3-10% graphite, about 1-5% molybdenum disulfide and/or tungsten disulfide, about <=10% calcium fluoride, etc. and about 3-20% metallic oxide such as silica, alumina, mullite, etc. to a matrix component consisting of about 60-80wt% copper, about 1-10% tin, about <=10% zinc, etc. to maintain a high coefft. of friction particularly in a high temp. region and to improve the wear resistance. The high coefft. of friction stable with thermal fading and water fading phenomena is obtd. and the material is adequate for dry process applications on account of the improved wear resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a friction material made of a sintered alloy of silk thread, which provides a stable high friction coefficient particularly against thermal fade phenomenon and water fade phenomenon, and improves wear resistance. It is designed to be suitable for dry use.

In recent years, various vehicles have become larger and faster, and the brakes installed on these vehicles, especially disc brakes on large motorcycles, have been exposed to harsh conditions where thermal fade and water fade are likely to occur. Yes, especially high performance,
High reliability is required. In organic and semi-metallic friction materials, the coefficient of friction decreases due to the thermal fade phenomenon and water fade phenomenon, resulting in insufficient performance.

On the other hand, in the case of metal friction materials, especially friction materials made of copper-based sintered alloys, the decrease in the friction coefficient due to the above phenomenon is
Because it is not so extreme, it is commonly used and has been reasonably effective.

However, the commonly used friction materials made of copper-based sintered alloys are not always satisfactory in terms of maintaining a stable high coefficient of friction against thermal and water fade phenomena, wear resistance, etc. There is a need for the development of improved friction materials.

The present invention was made in view of the above points, and by containing 1 to 20% by weight of ferrochrome in a copper-based friction material, heat-resistant fade characteristics and water-resistant fade phenomenon are improved, resulting in a stable and high coefficient of friction. The object of the present invention is to provide a friction material which is capable of providing abrasion resistance and also has two improvements in wear resistance.

The concept of the friction material of the present invention will be explained below.

The friction Pz material of the present invention is intended for copper-based sintered alloys in which a lubricating component and metal oxide are added to matrix components such as copper, tin, and zinc.The 3° matrix component maintains the strength of the metal. , has the role of stabilizing the coefficient of friction during braking, and its preferred composition range is copper 60 to 8 by weight.
0%, fy, 1-10%, zinc less than 10%.

The metal oxide is φ selected from silica, alumina, mullite, etc., and its effect is to increase the coefficient of friction and to scrape off deposits and reaction products generated on the mating material during the friction. Therefore, the content of the metal oxide is adjusted depending on the offensive ability against the opponent material, particle size, particle size distribution, etc. A preferred composition range is 3 to 20% by weight. This is because if the amount is too large, it will damage and wear out the mating material, and if it is too small, the abrasion coefficient will increase and the effect of scraping off transferred substances will be reduced. In addition, metal oxides have an effective effect on 4iT.
In order to achieve this, it is desirable to use hard particles with a Mohs hardness of 4 or more, and to have a particle size of 40 mesh or less.

The lubricating components are present at the interface between the mating material and the friction material to prevent seizure and can be expected to provide a stable frictional effect, and each component shares its own role in various temperature ranges. is necessary. Therefore, the lubricating component is selected from graphite, molybdenum disulfide, tungsten disulfide, calcium fluoride, and the like. The preferred composition range is 3 to 10% graphite, 1 to 5% binary f-hymolybdenum and/or tungsten disulfide, and 10% or less calcium fluoride by weight.

Additionally, lead is sometimes added to remove the "squeak" of the sliding sound that occurs during friction. Only 1
-1 Increasing the amount of lead added results in a decrease in the coefficient of friction.
group must be added.

Next, the purpose of adding ferrochrome is to maintain a high coefficient of friction especially in a high temperature range and to improve wear resistance '11. Therefore, ferrochrome is
It combines with the J-lux component, but has good wettability and has the role of preventing welding and plastic flow at high temperatures. That is, the matrix component, which is a copper alloy, usually softens slightly in a high temperature range and easily welds to the mating material.
In addition, wear increases due to plastic flow and the friction coefficient decreases. Therefore, in order to eliminate these drawbacks, the present inventors conducted extensive research and found that it is effective to add an appropriate amount of ferrochrome, which is an inexpensive material. In this case, high melting point metals such as cobalt, molybdenum, and tungsten are considered to be effective additives, but they have the disadvantage of being expensive.

It is also conceivable to reduce the amount of matrix components and increase the amount of metal oxides and graphite. However, the former has the disadvantage of abrading the mating material,
The latter has the disadvantage of lowering the coefficient of friction and also lowering the material strength, so it cannot be used.

On the other hand, ferrochrome is an inexpensive oil that meets JIS standards.
G2303 + As defined, there are high carbon ferrochromes, medium carbon ferrochromes, and low carbon ferrochromes, all of which are effective additive components in the present invention.

The amount of ferrochrome added is 1 to 20 by weight.
% is a suitable range. This is because if it is less than 1%, it will have little effect on maintaining the friction coefficient and wear resistance in the high-temperature range, and if it is more than 20%, it will reduce the friction properties and material strength.

In addition, unlike lumps when used as additives in can manufacturing, Ferroclaim is usually used as a material with a thickness of Lmm or less or more than 0.5 in order to not reduce material strength.
Particles or powder of less than mm in size are used.

An example of the friction material of the present invention will be described below.

Samples A to D were produced as friction materials of the present invention, and samples E to G were produced as conventional comparative materials. Its component composition is shown in Table 1.

The friction performance of Samples A to G in Section 1 was compared using a constant speed test machine. In this test method, two test pieces were pressed against a mating plate made of Fe12, and the conditions were that the sliding length was 2.0 m/sec, and the surface pressure was 5.

As a result, each sample A to D of the present invention had a friction coefficient of 0.
4 to 0.6, and it was found that the wear resistance and heat fade resistance were excellent. In addition, the level of squealing was within the range that was not bothersome, especially in samples C and D, which had almost no squealing.

This is due to the addition of lead as mentioned above.

On the other hand, Comparative Example E shows no wear of the friction plate and no damage to the mating plate, but shows inferior heat fade resistance and F.
, G samples have excellent heat fade resistance, but JS
There was a little bit more wear on the 1st rub board, and the opponent's board was attacked 7 times.

In addition, when the mating plate was made of stainless steel, the same test was conducted, but each sample showed a similar tendency.

Furthermore, a water fade test was conducted using a dynamo bench testing machine using a two-wheeled vehicle's brake system. The test conditions are as follows.

I = Ikg-m-S" V = 40 I (tr + / H P = Determined by decreasing helmet (0, 39) Water sprinkling amount = 75cc/min on one side of the disc Braking frequency ■ Hydraulic pressure setting test (0, 39G) 10 times@dry braking test
15 times θ wet braking test 15 times performance comparison is ')-1-71'' test deceleration x 100
(%) The retention rate was determined by dry test deceleration. As a result, samples A to D according to the present invention all showed a retention rate of 85% or more, but comparative samples E to G had a retention rate of about 80%.

Next, a criticality test was conducted to examine the appropriate range of the amount of ferrochrome added. Therefore, samples H and I were produced which were outside the range of 1 to 20% by weight. Its component composition is as shown in Table 2.

As a result, Sample H had an initial friction coefficient of 0.5, but the final friction coefficient decreased to 0.4 due to a thermal fade phenomenon. In addition, metal flow occurs on the friction surface, causing a slight amount of wear and tear.

On the other hand, in Sample I, the coefficient of friction fluctuates, chips occur on the friction surface, and there is a lot of wear due to the brittleness of the material.

For these reasons, it has been found that the range of addition of ferrochrome (FeCr) from 1 to 20% is suitable.

As explained above, the present invention provides a friction material made of a copper-based sintered alloy with a ferroflow unevenness weight ratio of 1 to 20.
%, it has the following effects.

First, it is possible to provide a dry sintered friction material whose friction coefficient changes little even in a high temperature range. This is because, as seen in the comparative example, conventional copper-based friction materials show a decrease in the coefficient of friction due to thermal fading, whereas the friction material of the present invention shows a decrease in the friction coefficient even in high-temperature friction sliding tests. , about 0
．． This is because a stable high friction coefficient of 4 to 0.6 is obtained.

The second objective is to provide a dry sintered friction material that has improved wear resistance in high temperature ranges. This is a J-Station building in which the friction material of the present invention is applied to disc brakes, with improved wear resistance.
- This means that the lining layer can be made thinner than the conventional lining layer, and its weight J11 can be reduced. In other words, reducing the weight of the lining layer directly leads to a reduction in vehicle weight, which has an important effect in meeting the strong demands of recent years for improved fuel efficiency and acceleration.

Thirdly, attack F against the opponent's board 11. It is an object of the present invention to provide a dry sintered friction material with improved properties. As mentioned above, this is due to improved wear resistance in high temperature ranges, which reduces wear on the friction material and reduces attack on the mating plate by deposits. This is due to the decrease in gender.

Fourth, a dry sintered friction material is provided that is also resistant to water fade phenomena. Because it is based on the matrix component of silk thread, it has considerable resistance to water fading, but the addition of ferrochrome further increases this resistance.

Patent applicant: Toshiba Tungaloy Corporation

Claims (1)

[Claims] Sintering of silk thread in which minor groove components such as graphite, molybdenum disulfide, tungsten disulfide, calcium fluoride, and gold scrap oxides such as silica, alumina, and mullite are added to matrix components such as silk, tin, and zinc. A friction material made of an alloy, characterized in that the sintered alloy contains 1 to 20% by weight of ferrochrome.