KR20050104982A - Method for manufacturing the materials impregnated grease having excellent property of lubrication - Google Patents

Abstract

The present invention relates to a material excellent in lubricity.

The present invention, in weight%, tin: 4-12%; And at least one selected from the group consisting of iron, titanium, lead, zinc, phosphorus and graphite: 0.2-15%; Uniformly mixing the powder composition consisting of the remaining copper; Pressure molding the mixture obtained in the above step, and then sintering at a temperature of 650 to 900 ° C. to prepare a molded sintered body having a porosity of 5 to 30%; And vacuum impregnating the grease to be sufficiently filled in the internal pores of the molded sintered body.

According to the present invention, it is possible to manufacture a material having improved lifespan by improving lubricity without deterioration of physical properties, and in particular, by manufacturing a current collector friction plate for pantograph using the present invention, it is possible to reduce the amount of abrasion of an electric lane and thus to save resources. In addition, less wear dust has the effect of protecting the environment.

Description

Method for manufacturing the materials impregnated grease having excellent property of lubrication}

The present invention relates to a material having excellent lubricity, and more particularly, to a material capable of improving lubricity by impregnating grease into a molded sintered body having pores. In particular, the present invention relates to a method for producing a material which is excellent in heat resistance, rain resistance and lubricity and which can be used for current collector friction plates for pantographs installed on the roof of a train or a locomotive.

In general, a current collector of an electric vehicle is installed on a roof of a tram or a locomotive to collect current while contacting a wire (trolly wire), and a current collecting friction plate is provided at a portion continuously contacting the wire. The current collector friction plate is required to have characteristics such as electrical conductivity, arc resistance, rain resistance and lubricity, and in particular, excellent wear resistance so as to be maintained in friction with wires for a long time.

Conventional current collector friction plate was prepared by mixing copper, tin and graphite in a predetermined ratio and at the same time by adding a pore generator to sinter the porous molded body, and then impregnated with conductive metal oil having excellent conductivity. However, since the current collector friction plate of the prior art increases the lubricity by impregnating conductive machine oil, a problem arises that the machine oil flows out of the mother body due to an increase in the temperature of the machine oil during use. In particular, during the rainy season, the conductive machine oil on the surface of the current collector plate is washed down, resulting in a sharp drop in lubricity and rapid wear.

The present invention is to solve the above-mentioned problems of the prior art, by replacing the machine oil with a vacuum-impregnated grease in a porous molded sintered body, by controlling the porosity of the molded sintered body of a material having excellent lubricity that can significantly improve wear resistance To provide a manufacturing method, the object is.

The present invention for achieving the above object,

By weight, tin: 4-12%; And at least one selected from the group consisting of iron, titanium, lead, zinc, phosphorus and graphite: 0.2-15%; Uniformly mixing the powder composition consisting of the remaining copper;

Pressure molding the mixture obtained in the above step, and then sintering at a temperature of 650 to 900 ° C. to prepare a molded sintered body having a porosity of 5 to 30%; And

And vacuum impregnating the grease to be sufficiently filled in the inner pores of the molded sintered body.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention can be used to improve the lubricity of the material in which the pores exist, especially when used in the current collector friction plate for pantograph can be improved to the maximum.

First, look at the reasons for limiting the ingredients of the material of the present invention.

The tin is a component for reinforcing copper base through alloying with copper which is a main component of the friction plate. If the content of tin is less than 4% by weight, the sintering ability of copper is lowered, so that the mechanical properties are not improved, and the life of the current collector friction plate is shortened. Since there is a problem of worsening the electrical wear, such as melting hand, the content is preferably limited to 4 to 12% by weight.

Furthermore, in the present invention, at least one member selected from the group consisting of iron, titanium, lead, zinc, phosphorus and graphite is added in addition to the above components.

The iron is an effective component for improving strength and hardness, and the titanium is an effective component for improving strength and hardness to arc resistance. The lead is an effective component for improving the lubricity of the current collector friction plate, the zinc is an effective component for enhancing the solid-solution strengthening effect and the wear resistance and lubricity with copper, and the phosphorus is an effective component for promoting the sintering power of copper and improving the corrosion resistance. to be. The graphite is a lubricating component that can reduce wear by interposing between the chariot line and the current collector friction plate to reduce the metal contact. In the present invention, it is preferable to add 0.2 to 15% by weight of at least one selected from the group consisting of iron, titanium, lead, zinc, phosphorus and graphite. If the content is less than 0.2% by weight, the effect as an additive cannot be obtained. If the content is more than 15% by weight, there is a problem of deteriorating electrical wear.

In addition to the above components, the remainder consists of copper.

In the present invention, it is possible to further add 0.05 to 2% by weight of the pore generator to the powder composition. If the amount of the pore-generating agent is less than 0.05% by weight, pore generation may be insufficient. If the amount of the pore-generating agent is more than 2% by weight, the pore may be so large that the mother tissue may deteriorate and the pore may be too large due to segregation. When the pore generator is added, it is more preferable to limit the content to 0.05 to 2% by weight.

Representative examples of the pore generator include zinc stearate, but are not limited thereto, and various pore generators may be used according to properties such as pore generation and molding lubrication. Examples of pore generators include metal-stearate including zinc stearate, stearic acid, and the like.

Hereinafter, the manufacturing method of the present invention will be described.

First, the powder composition prepared as described above is mixed uniformly. Thereafter, the mixture obtained above is press-molded and then sintered at a temperature of 650 to 900 ° C.

At this time, if the sintering temperature is less than 650 ℃ sintering is not possible, if it exceeds 900 ℃ there is a problem that copper drag phenomenon occurs due to oversintering, the sintering temperature is preferably limited to 650 ~ 900 ℃ Do. As for the sintered compact molded as mentioned above, it is more preferable that porosity is 5 to 30%. The reason is that when the porosity of the molded sintered body is less than 5%, problems may occur in which impregnation is difficult due to waste holes and high sintered density, and when it exceeds 30%, mechanical properties may be degraded.

Thereafter, grease is impregnated into the molded sintered body. Greases that may be used in the present invention include, but are not limited to, No.000, NLGI. The lead corresponds to a viscosity value of about 20000 ± 2000 cst at 25 ° C. (generally grease is not indicated by viscosity, but by a lead that indicates the degree of firmness). At this time, the grease should be sufficiently impregnated to be filled in all pores formed in the sintered body, the method will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic view of the apparatus required for carrying out the present invention. As can be seen from FIG. 2, a current collecting friction plate is placed in the container 1, and grease is placed in the container 2. Then, the vacuum is drawn out by the vacuum pump 3 to completely remove the air inside the current collector friction plate, and then the two vessels are heated until the main led of the grease is lowered. Thereafter, when the valve 4 is opened, the grease contained in the container 2 is moved to the container 1 according to the pressure difference, and may be rapidly impregnated into the mother body by a capillary phenomenon.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are only preferred embodiments of the present invention, and thus the present invention is not limited thereto.

Example 1

To prepare a powder composition as shown in Table 1. The prepared powder composition was molded at a pressure of 2.0 ton / cm 2 and then sintered at a sintering temperature of 850 ° C. for 3 hours under an ammonia gas atmosphere. At this time, each porosity is shown in Table 1 below.

After impregnating grease or machine oil into the pores of the mother body prepared as described above, the pressure was re-pressurized to 5.0 ton / cm 2 to measure physical properties using a Brinell hardness tester, a resistance tester, a tensile strength tester, and a Charpy impact tester. The results are shown in Table 2 below.

In addition, a change in the amount of wear of the current collector friction plate and the catenary using a wear tester, the results are shown in Table 3. The wear amount was measured under the conditions of running speed 60km / hr, applied current 500A, the rolling force of 5kgf in the rainy condition when the wear amount was measured.

Ingredient (% by weight) Impregnated Oil Type Porosity (%) Remark black smoke iron lead Pore generator Copper Invention 1 6 3 3 3 - 85 Greece 15 Invention 2 8 3 3 - - 86 Greece 10 Invention 3 8 3 3 - 0.2 85.8 Greece 11 Comparative Material 1 6 3 3 3 - 85 Machine oil 15 Comparative Material 2 8 3 3 - - 86 Machine oil 10 Zinc stearate is used as the pore generator.

division Density (g / cm 3) Hardness HB (10/500) Electrical resistivity (μΩ · cm) Tensile strength (kgf / ㎠) Impact strength (kgf · cm / ㎠) Invention 1 7.0 40 25 1390 124 Invention 2 7.5 48 18 1680 145 Invention 3 7.45 47 19 1630 140 Comparative Material 1 6.95 41 25 1450 120 Comparative Material 2 7.4 46 18 1600 140

division Wear change Current friction plate (g / 100km) Tank line (mm / 100 km) Invention 1 8.8 0.007 Invention 2 10.4 0.009 Invention 3 10.2 0.012 Comparative Material 1 13.7 0.025 Comparative Material 2 15.5 0.027

In Table 2, it can be seen that the invention material and the comparative material satisfying the scope of the present invention exhibits the same properties in physical properties.

However, as can be seen in Table 3, the invention material that satisfies the scope of the present invention is 30% or more improved compared to the comparative material, it can be seen that the amount of wear of the front line also reduced.

Example 2

To prepare a powder composition as shown in Table 4. The prepared powder composition was molded at a pressure of 3.0 ton / cm 2 and then sintered at a sintering temperature of 750 ° C. for 2 hours under an ammonia gas atmosphere. In this case, each porosity is shown in Table 4 below.

After impregnating grease or machine oil into the pores of the mother body prepared as described above, and re-pressurized at a pressure of 4.0ton / cm 2, physical properties were measured using a Brinell hardness tester, a resistance tester, a tensile strength tester, and a Charpy impact tester. The results are shown in Table 5 below.

In addition, a change in the amount of wear of the current collector friction plate and the catenary using a wear tester, the results are shown in Table 6. The wear amount was measured under the conditions of running speed 80km / hr, applied current 500A, the rolling force 5kgf in the rainy conditions when measuring the wear amount.

Ingredient (% by weight) Impregnated Oil Type Porosity (%) Remark black smoke titanium lead zinc sign Pore generator Copper Invention 4 7 4 3.5 - - 0.5 - 85 Greece 15 Invention 5 7 4 - 3.5 - 0.5 - 85 Greece 15 Invention 6 8 5 - 3 3 - - 81 Greece 20 Invention 7 8 5 - 3 3 - 0.75 80.25 Greece 22 Comparative Material 3 7 4 - 3.5 - 0.5 - 85 Machine oil 15 Comparative Material 4 8 5 - 3 3 - - 81 Machine oil 20 Zinc stearate is used as the pore generator.

division Density (g / cm 3) Hardness HB (10/500) Electrical resistivity (μΩ · cm) Tensile strength (kgf / ㎠) Impact strength (kgf · cm / ㎠) Invention 4 7.3 44 26 1450 119 Invention 5 7.2 42 25 1410 125 Invention 6 6.9 43 22 1180 101 Invention 7 6.7 40 21 1040 107 Comparative Material 3 7.3 43 24 1300 120 Comparative Material 4 6.95 41 23 1200 105

division Wear change Current friction plate (g / 100km) Tank line (mm / 100 km) Invention 4 6.5 0.018 Invention 5 7.5 0.013 Invention 6 8.1 0.011 Invention 7 8.5 0.014 Comparative Material 3 13.5 0.030 Comparative Material 4 13.0 0.035

In Table 5, it can be seen that the invention and the comparative material satisfying the scope of the present invention exhibits the same characteristics in physical properties.

However, as can be seen in Table 6, the invention material that satisfies the scope of the present invention has improved durability by 40% or more compared to the comparative material, in particular, in the case of Inventive Material 4, the durability is improved by about 2 times. In addition, it was found that the amount of wear of the tank lane was also reduced.

As described above, according to the present invention, it is possible to manufacture a material having improved lifespan by improving lubricity without deterioration of physical properties, and in particular, by manufacturing the current collector friction plate for pantograph using the present invention, it is possible to reduce the amount of abrasion of the front line. Therefore, it is possible to save resources and to protect the environment with less wear dust.

1 is a graph showing the weight loss of each temperature of the present invention and the prior art material.

2 is a schematic diagram of an apparatus required for practicing the present invention.

* Description of the symbols for the main parts of the drawings *

1, 2 ... Container 3. Vacuum pump

4.valve

Claims (2)

By weight, tin: 4-12%; And at least one selected from the group consisting of iron, titanium, lead, zinc, phosphorus and graphite: 0.2-15%; Uniformly mixing the powder composition consisting of the remaining copper; Pressure molding the mixture obtained in the above step, and then sintering at a temperature of 650 to 900 ° C. to prepare a molded sintered body having a porosity of 5 to 30%; And And vacuum impregnating the grease to be sufficiently filled in the internal pores of the molded sintered body. The method of manufacturing a grease impregnated material having excellent lubricity according to claim 1, further comprising 0.05 to 2% by weight of a pore generator in said powder composition.