JPH0238813B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to friction materials for railways, more specifically, increased adhesion brake shoes, snow-resistant brake shoes, snow-resistant day slopes, high-speed friction materials, etc., for improving the adhesion (frictional force) between rails and vehicles, and for general-purpose brake shoes ( This invention relates to friction materials for railways intended to improve water resistance as linings. Conventional formulations of railway friction materials for such purposes include those that add a large amount of metal powder to achieve transfer to wheel and rail surfaces and break water film effects, and those that add abrasives to achieve the effect of adhering to wheel and rail surfaces and breaking the water film. A method that improves the water film breaking effect by cleaning and biting is being implemented. However, the former composition has good heat conduction, so
This has the disadvantage of increased wear on the brake shoe, and the latter composition also has the disadvantage of increased wear on the wheel, resulting in grooving or concave wear. The present invention has been made to eliminate such drawbacks, and is characterized by using brass fibers and/or aluminum fibers in combination with steel fibers, and microscopically reduces friction in the friction surface area occupied by these metal fibers. It is possible to provide a railway friction material that becomes almost alloyed by heat and becomes easy to transfer, and when used together with aluminum fiber, has excellent corrosion resistance and low contact resistance due to the formation of an aluminum film. This effectively achieves the purpose of preventing seizure and increasing wear. The specific composition of the railway friction material of the present invention is as follows. Steel fiber 5-65% by weight Brass fiber and/or aluminum fiber (aluminum fiber and/or aluminum alloy fiber) 0.5-20% by weight Iron powder (including low-density iron powder and cast iron powder)
5-50% by weight Copper 10% by weight or less Graphite 10-30% by weight Inorganic filler 5-15% by weight Organic friction modifier 10% by weight or less Resin (phenolic resin and other thermosetting resin) 5-15% by weight % It is desirable to use the above metal fibers (steel fiber, brass fiber, aluminum fiber) with a diameter (thickness) of 100 μ or less and a length of 10 mm or less, and metal powder (iron powder, copper powder). The particle size is preferably 100 mesh or less. The iron powder may include low-density iron powder, cast iron powder, etc. having an apparent density of, for example, around 1.0. As mentioned above, the railway friction material of the present invention is a metallic shoe in which metal powder, etc. is bonded with resin while intertwining metal fibers, as seen from its compounding composition. It is characterized by excellent water resistance and thermal stability, and according to the present invention, the following effects can also be obtained. (1) Due to its strong metallic properties, it generates a lot of frictional heat on the surface and has great adhesion and water resistance effects. (2) Low melting point metals (Cu, Al) that easily transfer to the mating material
Because it uses aluminum fibers, it has a great water resistance and thickening effect, and because aluminum fibers are intertwined with brass fibers and aluminum fibers at the same time, it has a great thickening effect and signal interference effect as mentioned above. There is. (3) Due to the small amount of resin and strong fibrous properties, it becomes porous and has a great drainage effect. (4) By adjusting the size and length of the fibers and the particle size of the metal powder, baking, adhesion, and grinding with the mating material occur on the very surface, resulting in extremely low wear on both the mating material and the friction material. be able to. (5) It contains graphite, a solid lubricant, and at the same time has less wear due to the oxide film that forms at high temperatures. (6) Because it has very good thermal conductivity, the friction material absorbs and diffuses energy from high speeds, and because it is porous, it prevents direct heat conduction and prevents thermal deterioration of the resin, resulting in an f value (coefficient of friction). , wear balance is easy to maintain. Examples of the present invention are shown below. Examples 1 to 3 Friction materials for railways were manufactured according to a conventional method using the formulations shown in the table below. Example 1 shows an example of an increased adhesion brake shoe, Example 2 shows an example of a snow-resistant brake shoe, and Example 3 shows an example of a high-speed brake shoe.

[Table] We investigated the relationship between the metal particle size (mesh) and the wear amount (g) of the friction material for the blending composition of Example 1, and obtained the results shown in diagram A in Figure 1. The particle size is less than 100 mesh, especially 100 to 350
It turns out that mesh is desirable. In addition, we investigated the relationship between the diameter of the metal fiber (10 ^-3 mmφ) and the amount of wear on the friction material, and obtained the results shown in curve B in Figure 1. From this, we found that the diameter of the metal fiber is less than 100 μ (25 ~
It can be seen that a range of 100μ) is preferable. Regarding the blending composition of Example 2, 1000c.c./min40
When we investigated the relationship between the N value (number of brakes) and the f value (friction coefficient) under watering conditions at ℃, the f value (friction coefficient μ) of the invention product C showed a stable value, whereas
In conventional product D, the f value decreased significantly as the N value increased, and it was confirmed that the product of the present invention is superior.

[Brief explanation of drawings]

Figure 1 is a chart showing the relationship between the metal powder particle size and metal fiber diameter and the friction material wear amount in the product of the present invention (Example 1), and Figure 2 is a chart showing the relationship between the product of the present invention (Example 2) and the conventional product. 2 is a chart showing a comparison of the relationship between the number of brakes and the coefficient of friction. A...Relationship curve between metal powder particle size and wear amount, B...
...Relationship curve between metal fiber diameter and amount of wear, C...Product of the present invention, D...Conventional product.

Claims (1)

[Claims] 1. 5-65% by weight of steel fiber, 0.5-10% by weight of brass fiber and/or aluminum fiber, 5-50% by weight of iron powder, 0-10% by weight of copper powder, 10-20% by weight of graphite. %, inorganic filler 5-15% by weight, organic friction modifier 0-10% by weight, resin 5-15%
% by weight, the steel fiber, brass fiber, and aluminum fiber have a diameter of 25 to 100 μm and a length of 10 mm or less, and the metal powder particle size of the iron powder and copper powder is 100 to 350 mesh. A friction material for railways characterized by: 2. The railway friction material according to claim 1, wherein the iron powder contains low-density iron powder and cast iron powder.