JPS58153745A - Dry sintered friction material - Google Patents

Abstract

PURPOSE:To enhance the friction coefficient of the friction material and to improve its aggresive tendency to a facing member and its judder, by letting a bronze sintered alloy material have a composition comprising the specified amounts of Cu, Sn, metal oxide composed of hard particles, graphite, MoS2, Pb and Mn. CONSTITUTION:The dry sintered friction material is made of a bronze sintered alloy having a composition of, by wt%, 60-80 Cu, 3-20 Sn, 3-20 metal oxide composed of hard particles, 3-10 graphite, 1-5 MoS2, >8 Pb and >15 Mn. As said metal oxide, hard particles, e.g. alumina, silica or mullite, having Mohs' hardness above 4 are used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bronze-based dry sintered friction material that can provide a stable friction coefficient and improve its aggressiveness against mating materials.

Conventionally, dry sintered friction materials have been required to have a high friction coefficient and seizure resistance, and to be resistant to thermal fade phenomena, water fade phenomena, etc. that appear as a decrease in the friction coefficient.

However, with conventional bronze-based sintered friction materials,
All of the above requirements have not yet been met, and further development from the aspect of component composition is desired.

The present invention has been made to meet this demand, and is a dry sintered friction material made of a bronze-based sintered alloy, in which the sintered alloy has a weight ratio of 60 to 80% copper and 3 to 3% tin.
Provided is a dry sintered single friction material containing 20% of metal oxide, 3 to 20% of metal oxide consisting of hard particles, 3 to 10% of graphite, 1 to 5% of molybdenum disulfide, 8% or less of lead, and 15% or less of manganese. It is something.

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

The dry sintered friction material of the present invention uses a bronze-based sintered alloy as a matrix component.

Its composition is determined by weight ratio (
The same applies hereinafter), and a range of 60 to 80% copper and 3 to 20% tin is selected. The selection criterion for this range is based on the stability of the friction surface. In particular, bronze-based matrix materials are related to material strength and stabilize the coefficient of friction during braking, and also form a hard copper oxide film on the surface due to the heat generated between it and the mating plate. shows resistance to water fade phenomenon. It also has excellent resistance to thermal fading and provides a stable friction surface.

Furthermore, in the dry sintered friction material of the present invention, alumina (A
l2O3), silica (SiO2), mullite (3Al
It contains 3 to 20% of metal oxide consisting of hard particles such as 2O3.2SiO2). The selection criteria for this content is based on the ability to withstand high-load, high-temperature frictional sliding. Therefore, depending on the aggressiveness towards the opponent material,
Its content is determined within the range of 3 to 20%. In this case, these metal oxides have the effect of increasing the coefficient of friction and scraping off deposits and reaction products generated during the friction. If the amount is too small, this effect will be small, and if the amount is too large, the opposing material will be attacked radically, so a range of 3 to 20% is suitable. The hardness of the metal oxide is preferably 4 or more on the Mohs hardness scale, where diamond is 10.

Further, the dry sintered friction material of the present invention contains 3 to 10% graphite,
Molybdenum disulfide (MOS2) 1-15% and lead (P
b) Contains 8% or less. These generally exhibit lubricity in their respective temperature ranges and act as friction coefficient improvers when the temperature exceeds their respective temperature ranges. In this case, lead, which is commonly used as a lubricating component, has one aspect of lowering the coefficient of friction, but on the other hand, it is expected to improve squeal and wear resistance. Therefore, the dry sintered friction material of the present invention has a relatively high coefficient of friction of about 0.4 to 0.5, and has improved aggressiveness and squealing against mating materials.

Furthermore, in the dry bonded friction material of the present invention, manganese is particularly added in an amount of 15% or less. This is because the addition of manganese has the effect of reducing the oxide film of other metals during sintering and improving sinterability. This is also because a part of manganese has an effective effect of stabilizing the friction surface by MNO2.

For these reasons, the dry sintered friction material of the present invention is a material with a relatively high coefficient of friction, has high resistance to thermal fade phenomena and water fade phenomena, and has improved aggressiveness and squealing against mating materials. This is what is being done.

Next, an example of the dry sintered friction material of the present invention will be described.

As samples, a dry sintered friction material of the present invention and a conventional comparative material were manufactured. That is, materials according to the present invention are A to D, and materials related to conventional comparative materials are E to D.
G, component composition as shown in the following table (unit weight %)
).

Next, the performances of A to G were compared using a constant speed friction tester. In this test, two test pieces were pressed against a mating material made of FC-20, and the conditions were a sliding speed of 20 m/sec and a second surface pressure of 5 kg/cm2.

As a result, A to D of the present invention have a relatively high coefficient of friction within the range of 0.4 to 0.5, do not attack the mating plate, and have excellent heat fade resistance. there were.

In addition, the level of squeal was within the range that was not bothersome, and in particular, for C, there was almost no squeal.

On the other hand, the conventional E did not attack the opponent board, but showed slightly inferior heat resistance and fade resistance, while the F had excellent heat resistance and fade resistance, but attacked the opponent board significantly. Furthermore, although G has excellent heat fade resistance, it attacked the opponent's board extremely well.

In addition, in the dry sintered friction material of the present invention, the effect of adding Mn is remarkable, and various tests were conducted separately regarding the amount of Mn added. It was removed because it caused burns and worsened the workability of sintering.

Further, a separate test was conducted on metal oxides, and it was found that Mohs' hardness of 4 or higher is suitable, and that the method can also be applied to metal oxides such as mullite.

As explained above, the present invention provides the following effects by adding manganese to a bronze-based dry friction material as a specific component.

(1) A dry sintered friction material having a stable friction coefficient is provided. In the present invention, the friction coefficient is relatively high at about 0.4 to 0.5, and the heat fade resistance is also excellent. This means that a stable friction surface can be obtained even when sliding at high speeds, making it particularly suitable for automobiles.

(2) A dry sintered friction material with improved aggressiveness and squeal against a mating plate is provided. Along with this, the aggressiveness towards the opponent's board also increases. However, in the present invention, while the coefficient of friction is high, the rate of wear is also suppressed. Therefore, improvement in aggressiveness also leads to a reduction in so-called barking.

(3) A dry sintered friction material is provided which is also improved against the water fade phenomenon. In the present invention, since it is based on a bronze-based matrix and manganese is added, it is resistant to water fading, and is particularly suitable for exposed two-wheeled vehicles. In this case, if stainless steel is used as the mating plate, the problem of rust will be solved at the same time.

Claims (2)

[Claims] (1) In a dry sintered friction material made of a bronze-based sintered alloy, the sintered alloy has a weight ratio of 60 to 80% copper and 3 to 2% tin.
0%, 3 to 20% of metal oxides consisting of hard particles, 3 to 10% of graphite, 1 to 5% of molybdenum disulfide, 8% or less of lead, and 15% or less of manganese. material. (2) The metal oxide is composed of hard particles having a Mohs hardness of 4 or more.
Dry sintered friction material described in Section 1.