JPH05287318A - Production of carbonaceous collecting sliding material - Google Patents

Abstract

PURPOSE:To obtain a homogeneous and high-strength carbonaceous collecting sliding material (contact strip) capable of excellently following a trolley wire and enriched in self lubricity and wear resistance. CONSTITUTION:Material contg., by weight, 35-70% powdery metal, 0.2-8% boron nitride and the balance powdery carbon is mixed and compacted. The compact is sintered in a nonoxidizing atmosphere at a high temp. where the metal is not eluted from the compact to obtain the sintered compact having 2.2=4.0g/cm<3> apparent density and <=1,700muOMEGAcm electric resistivity. Besides, cold isostatic pressing or multistage pressing by a metallic mold is used to obtain a homogeneous and high-strength material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a carbon-based current-collecting sliding material mainly used as a high-low speed pantograph current-collecting sliding plate for electric vehicles.

[0002]

2. Description of the Related Art One of the inventors of the present invention has previously made a sintered alloy T as a conventional low-speed conventional railway for low speed railways and a private iron pantograph sliding plate.
C103 (Patent No. 419107, Japanese Patent Publication No. 38-180)
58), and a sintered alloy TCK16 (Patent No. 509195, as a high speed Shinkansen pantograph sliding plate).
Japanese Patent Publication No. 42-14286), and TCCR2 (Patent No. 1053) as a pantograph sliding plate for cold regions.
No. 072, Japanese Examined Patent Publication No. 55-44143) and the like, which have been put to practical use.

However, the above-mentioned sintered alloy slide plates for electric vehicles, which have been practically used in the past, contain about 94 to 98% by weight of metal, and therefore, when they are separated from the hard copper trolley wire, both of them are used. In addition, since the main component is a metal, a large arc is likely to be generated, which easily causes arc damage on both sides, which may increase the number of times the trolley wire is replaced and the frequency with which the sliding plate is replaced. .. In addition, since most of the conventional sintered alloy sliding plates are made of metal as described above, when sliding with the counterpart hard copper trolley wire, sliding noise due to sliding between metals is high, and It has been demanded to minimize such noise pollution.

Therefore, the inventors of the present invention disclosed in Japanese Patent Laid-Open No. 60-2384.
In 02, we proposed a sintered body composed of carbon powder excluding natural graphite and artificial graphite and a metal powder with good conductivity, and a current-collecting sliding material obtained by waterproofing this sintered body. Improved wear resistance compared to sliding plates, reduced trolley wire wear,
We were able to show great results in noise prevention.

[0005]

However, the load condition applied to the slide plate becomes more and more severe due to the increase in the current collection current accompanying the recent increase in vehicle speed and the spread of cooling equipment. It is difficult to take sufficient measures for the current situation and future use of the sliding plate material in terms of current collection capacity and wear resistance.

Therefore, in the present invention, in order to maintain good characteristics even if the current collecting current increases, the electrical resistivity is lowered to increase the current collecting capacity, and the lubrication performance is further improved to obtain more effective noise. It is an object of the present invention to provide a homogeneous and high-strength carbon-based current-collecting sliding material that reduces the amount of wear and suppresses the wear of the trolley wire.

[0007]

In order to solve the above problems, the present invention provides a metal powder 35 having good conductivity in a weight ratio.
~ 70%, boron nitride 0.2 ~ 8%, powder material consisting of the balance carbon powder is mixed and pressure molded, the molded body in a non-oxidizing atmosphere at a high temperature in the range where the metal does not elute from the molded body The apparent density of the sintered body obtained by sintering is 2.
It is characterized in that the pressure molding conditions are set so that the electric resistivity is 2 to 4.0 g / cm ³ and the electric resistivity is 1,700 μΩcm or less.

As a forming method for producing the above-mentioned homogeneous and high-strength material, there are a cold isostatic pressing method and a multi-step pressing method using a die.

[0009]

As a result of various experiments, the inventors of the present invention kneaded aggregates such as crushed coke and granulated carbon black and a binder such as coal tar pitch as the carbon powder suitable for the intended sliding plate. It was found that the fine powder obtained by extracting the spherulite formed by heat-treating the powder after pulverization or the coal tar pitch, and filtering, drying, calcining and classifying the mixture effectively works.

These sintered bodies of carbon powder alone are rich in self-lubricating property and arc resistance with respect to the trolley wire, and have low noise during sliding. Moreover, the sliding surface has a mirror surface. Also, I learned that the sliding surface of the opponent trolley wire is also a mirror surface. However, the apparent density of sintered carbon powder alone is 1.65 g / c.
m ³ or less, bending strength 400 kgf / cm ² or less, electrical resistivity 50
Since it is as high as 00 to 9000 μΩcm, the current collection capacity is small,
Since it has low thermal conductivity, it is unsuitable as a sliding plate for electric vehicles. By the way, the copper-based materials that have been used in the past,
The iron-based sintered alloy has a density of 7.0 to 8.0 g / cm ³ , an electric resistivity of 15 to 50 μΩcm, a bending strength of 4200 kgf / cm ² or more, a large current collecting capacity, and a high thermal conductivity.

Therefore, the inventors of the present invention combine the respective characteristics of the sintered body of the above-mentioned carbon simple substance and the sliding plate made of the sintered alloy which has been practically used in the past, and therefore, the carbon powder and the metal powder having good conductivity are combined. In order to further improve the lubrication performance, we have come up with the idea of making a sintered body with a mixture, and as a result of various experiments, a good conductive metal powder 35-70% by weight ratio, boron nitride 0.2-8 %, Powder material consisting of the balance carbon powder, pressure-molded, and sintered the molded body in a non-oxidizing atmosphere at a high temperature within the range where metal is not eluted from the molded body, thus obtained sintered body It was confirmed that when the pressure molding conditions were set so that the apparent density of the product was 2.2-4.0 g / cm ³ and the electrical resistivity was 1,700 μΩcm or less, it showed extremely excellent results as an electric rolling stock. did. The pressure molding method includes a cold isostatic pressing method and a multi-step pressing method using a mold.

The sintered body obtained by mixing boron nitride according to the present invention has a specific wear amount of ⅓ to ⅕ as compared with the carbon-metal sintered body containing no boron nitride. It was confirmed to decrease. This means that the heat-resistant temperature of boron nitride, which is a lubricating component, in an oxidizing atmosphere is 900 ° C.
Since it is higher than 0 ° C, it can maintain a low friction coefficient even under high temperature sliding, and its oxidation consumption is higher than that of carbon even for the arc generated when the sliding plate and the trolley wire are separated during running. This is due to the small number and the utilization of homogeneous and high-density molding methods.

The carbon-boron-nitride-metal sintered body, which is the current-collecting sliding material obtained by the present invention, requires an apparent density of 2.2 to 4.0 g / cm ³ , as described above. When it is more than 0.0, it gradually approaches the characteristics of the conventional sintered alloy sliding plate, and the mechanical strength becomes large, but the weight becomes excessive and loses the characteristics as a sliding plate using carbon, and it becomes a pantograph for trolley wire. Trackability is deteriorated, and an arc is often generated due to disconnection.
If the apparent density is less than 2.2, the electrical resistivity will be 200.
When it becomes 0 μΩcm or more, the characteristics of metal are gradually lost, the current collecting capacity is lowered, and the thermal conductivity is lowered, which causes local heat generation of the sliding plate. The carbon-boron-nitride-metal sintered body having an apparent density of 2.2 to 4.0 g / cm ³ obtained according to the present invention has a Shore hardness of 70 to 110 and a bending strength of 750 to 130.
It is 0 kgf / cm ² , and can maintain the hardness and mechanical strength required for the sliding plate. If the boron nitride content is less than 0.2%, the effect of improving the lubricity of the sintered body is small. If it exceeds 8%, the bending strength is lowered and the mechanical strength cannot be maintained.

When it is desired to further reinforce the mechanical strength, the bottom portion on the opposite side of the sliding surface with respect to the trolley wire is wrapped with a good conductive metal plate such as an iron plate or a copper plate having a mechanical strength higher than that of the aluminum plate. It can be achieved easily and easily.

The carbon-boron-nitride-metal sintered body according to the present invention has a reduced porosity and an apparent density of 2.2 to 4.
In order to achieve 0 g / cm ³ , pressure molding is performed at a high pressure of ² T / cm ² or more, but when rainfall continues for a long time, water content advances, and the specific wear amount of the sliding plate and the wear rate of the trolley wire are higher than in fine weather. Is expected to deteriorate. In order to improve wear resistance even in such rainy weather, in the sintered body obtained as described above,
The sintered body may be waterproofed by impregnating it with a resin that does not increase the electrical resistivity as much as possible.

As described above, the carbon-boron nitride-metal based sintered body obtained according to the present invention is prepared by mixing carbon, boron nitride and metal in the form of powder and press-molding the sintered body. Therefore, as compared with the case where the carbon base material is melt-impregnated with a metal, there is no unevenness in the components, and a product suitable for the above-mentioned use can be arbitrarily manufactured.

[0017]

EXAMPLES Specific examples of the present invention will be described below.

Example 1 (1 to 1 to 6) A petroleum coke crushed to 200 mesh or less has a softening point of 8
After blending 40% by weight of medium pitch at 5 ° C., 20 with a kneader
The mixture was kneaded for 2.5 hours while heating to 0 ° C. The kneaded product was allowed to cool and then pulverized to obtain a carbon powder that passed through 100 mesh.

Next, the carbon powder, copper powder and copper alloy powder of 80 mesh or less and boron nitride of 100 mesh or less were mixed and mixed in the proportions shown in the left column of Table 1, and the mixed powder was molded. 25 × 43 × 34 with a pressure of 1 T / cm ²
After temporary molding to a size of 0 mm, the temporary molded body is vacuum-packed with a nylon sheet and placed in a pressure vessel, and isotropic pressure of 4 T / cm ² is applied by a cold isostatic pressing method, X40
A molded product of × 328 mm was prepared. Further, the molded body was sintered at 970 ° C. in a non-oxidizing atmosphere, and carbon, boron nitride,
A sintered body made of a metal having good conductivity was obtained. In Example 1-3, the obtained sintered body was dipped in an alcohol solution having a resin weight percent concentration of 45%, impregnated under reduced pressure, and then heat-cured.

[0020]

[Table 1]

Example 2 (6 of 2 to 2) A spherulite formed by heat-treating coal tar pitch was extracted, filtered, dried, calcined and classified to obtain an average particle size of 13 ~ 17μm carbon powder (trade name KMFC
Kawasaki Steel) and 80 or less mesh copper powder and copper alloy powder and 100 mesh or less boron nitride in the proportions shown in the left column of Table 2, and after mixing, seal this mixed powder in a rubber mold. Put in a pressure vessel and cold isostatically press to 4T
An isotropic pressure of / cm ² was applied to obtain a molded body of 24 × 40 × 328 mm. Further, the molded body is subjected to 970 in a non-oxidizing atmosphere.
Sintering was performed at ℃, and a sintered body made of carbon, boron nitride, and a metal having good conductivity was obtained. In Examples 2 and 3, the sintered body was immersed in an alcohol solution having a resin weight percent concentration of 45%, impregnated under reduced pressure, and then heat-cured.

[0022]

[Table 2]

Example 3 (6 of 3 to 1) The carbon powder (trade name KMFC) used in Example 2, copper powder and iron powder of 80 mesh or less and boron nitride of 100 mesh or less are shown in Table 3. After mixing and mixing in the proportions shown in the left column, this mixed powder is packed in a mold and pressed at a pressure of 1 T / cm ² for 25
After temporary molding into a size of × 43 × 340 mm, the temporary molded body is vacuum-packed with a nylon sheet and placed in a pressure container, and an isotropic pressure of 4 T / cm ² is applied using a cold isostatic pressing method. In addition, a molded body of 24 × 40 × 328 mm was prepared. Further, the molded body was sintered at 1050 ° C. in a non-oxidizing atmosphere to obtain a sintered body made of carbon, boron nitride and a metal having good conductivity. In Example 3-3, the sintered body was immersed in an alcohol solution having a resin weight percent concentration of 45%, impregnated under reduced pressure, and then heat-cured.
Further, in this embodiment, the electric resistivity is 1,700 μΩc.
The reason why the iron powder is blended within the range not exceeding m is to reduce the weight and cost.

[0024]

[Table 3]

Example 4 (6 of 4 to 4) The carbon powder (trade name KMFC) used in Example 2, copper powder of 80 mesh or less and boron nitride of 100 mesh or less are shown in the left column of Table 4. After mixing and mixing at the ratios shown, this mixed powder is packed in a mold and subjected to primary pressing at 1 T / cm ² , and the pressed state of 1 T / cm ² is maintained in the mold for 30 seconds. After 30 seconds, 2.5T / cm ² was added as a secondary pressure, and 25 ×
A molded body of 40 × 340 mm was prepared. Further, the molded body was sintered at 970 ° C. in a non-oxidizing atmosphere to obtain a sintered body made of carbon, boron nitride and a metal having good conductivity. In addition, in 4-3 of Example, the sintered body was dipped in an alcohol solution having a resin weight percent concentration of 45% and impregnated under reduced pressure.
The resin was heat-cured. Note that this embodiment has 2
Although an example of step forming has been shown, multistage forming such as three step forming can be performed.

[0026]

[Table 4]

Comparative Example As a comparative example, the above-mentioned sintered alloy TC103 (component weight%, tin 9, chrome 5, phosphorus 0.5, graphite 2.5, balance copper) and the sintered body of Example 2 were used. Two kinds of carbon-metal sintered bodies excluding boron nitride from the components, and JP-A-62-238.
402 Example 1-5 was used. The components are shown in the left column of Table 5 below. Incidentally, JP-A-62-2
Since the component ratio of 1 of 38402 in Example 5 is volume%, when converted into weight%, Cu is about 65% and the balance is C.

[0028]

[Table 5]

Ten pieces of 10 × 10 × 60 mm test pieces were cut out from each of the current-collecting sliding materials obtained in the above Examples and Comparative Examples, and the physical properties thereof were measured. The results are shown in the columns of Tables 1 to 5.

Next, 10 × 25 × 90 mm test pieces were cut out from the current collecting sliding materials obtained in the above-mentioned respective examples and comparative examples, each test piece was attached to a rotary sliding tester, and a pressing force of 5 kgf, Energizing current AC100A, sliding speed 65km / H,
It was slid on the trolley wire for 60 minutes at 542r / p / m without lubrication. Measure the specific wear amount of the test piece when it was slid (wear volume mm ³ when the sliding plate was pressed against the trolley wire with a load of 1 kgf and slid a distance of 1 mm) and the wear thickness of the mating trolley wire. Wire wear rate (trolley wire wear thickness mm
Table 10 shows the sliding noise (horn) caused by the overhead wire and the sliding plate.
As shown in.

In the structure of the rotary sliding tester, a hard copper trolley wire with a groove (cross section 110 mm ² ) practically used by JR is arranged in a perfect circle with a circumference of 200 cm, and the test piece is attached to the trolley wire. It is designed to slide with a lateral amplitude of 70 mm while pressing with a force of 5 kgf. Therefore, when the test piece is rotated at 542 r · p · m for 60 minutes, the test piece passes through the same portion of the trolley wire 32,520 times. Further, the trolley wire wear measurement was carried out by measuring the thickness wear of predetermined 8 places of a 200 cm true circle with a micrometer.

The sound level meter was set at a position 1 m from the test slide plate attached to the rotary sliding tester. Note that the noise horn value due to the trolley wire and the sliding plate is greater than the noise horn value generated when the sliding plate is attached to the rotary testing machine and rotated, and when the testing machine is rotated without the sliding plate attached. It was calculated by subtracting the generated sound horn value.

[0033]

[Table 6]

[0034]

[Table 7]

[0035]

[Table 8]

[0036]

[Table 9]

[0037]

[Table 10]

As is clear from Tables 1 to 4, the current-collecting sliding material obtained according to the present invention has physical properties required for an electric car pantograph sliding plate. The current-collecting sliding material obtained according to the present invention is slightly inferior in strength to conventional sintered alloy-based contact plates, but has the strength required for practical use, and if necessary, FIG. As shown in FIG. 2, an inclined surface 1a is formed on both sides of the bottom of the sliding plate 1 and becomes wider toward the bottom surface, and an iron plate or a copper plate 2 with good conductivity and rust-proof plating is applied from the bottom surface to the inclined surfaces on both sides. It can be easily and easily reinforced by wrapping it in.

The current-collecting sliding material obtained by the present invention is
As is clear from Tables 6 to 9, the sliding plate specific wear amount is 1 to 6, 6 to 1 to 2 to 6, 2 to 6, 3 to 1 to 3 to 6, 4 to 1 to 4 for 6 in the first embodiment. 0.024 × 10 on average
~ ⁶ , 0.022 x 10 ~ ⁶ , 0.028 x 10 ~ ⁶ , 0.03
5 × 10 ~ ⁶ mm ³ /kgf.mm, conventional sliding plate made of sintered alloy T
Compared with 2.70 × 10 to ⁶ mm ³ /kgf.mm of C103 (Comparative Example 1), the wear resistance was remarkably improved, and a carbon-metal sintered body containing no boron nitride (comparative example) was used. It was confirmed that the wear resistance was three times or more that of Examples 2 and 3) and JP-A-60-238402 (Comparative Example 4). Similarly, the wear of the trolley wire is 0.0003 on average.
5, 0.0036, 0.00050, 0.0038 mm /
10,000 panta, 0.0 of the conventional sintered alloy sliding plate TC103
It is much smaller than a 24 mm / 10,000 panta and does not contain boron nitride, and a carbon-metal sintered body and JP-A-60-
It has been clarified that it is significantly reduced as compared with 238402. Furthermore, it should be noted that the sliding surfaces of both the sliding plate and the trolley wire were mirror surfaces, and the life of the sliding plate and the trolley wire could be remarkably extended. Furthermore, it has been confirmed that the sliding noise can be reduced to the extent that it does not cause any problem as compared with the conventional one, and similarly, a carbon-metal sintered body containing no boron nitride and JP-A-60-2.
It was clarified that it was reduced by more than 1/2 compared with 38402.

As is clear from Tables 1 to 4 and Tables 6 to 9 of each example, even if a single metal powder, a mixed powder or an alloy powder is used as a metal having good conductivity, Wear resistance is almost unchanged. Therefore, the metal powder applied to the present invention includes a single powder and a mixed powder, and as a measure for preventing water absorption during rainfall, the sintered body is impregnated with resin to the extent that the electrical resistivity does not increase. It may be cured and waterproofed, which is also included in the present invention.

[0041]

As described above, according to the present invention, the followability of the trolley wire is good, the self-lubricating property, the arc resistance and the wear resistance are excellent, and the large current collecting capacity is obtained. ,
Further, since the sliding noise with the trolley wire can be reduced, it is very useful as a current collecting sliding material for electric vehicles.

[Brief description of drawings]

FIG. 1 is a plan view showing a reinforcing example of a current-collecting sliding material obtained according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sliding plate, 1a ... Slope, 2 ... Reinforcing metal plate.

Claims (4)

[Claims] 1. A metal powder 35 to 7 having good conductivity in a weight ratio.
A powder material consisting of 0%, boron nitride 0.2 to 8%, and the balance carbon powder is mixed and pressure-molded, and the molded body is heated in a non-oxidizing atmosphere at a high temperature in a range where metal is not eluted from the molded body. The apparent density of the sintered body obtained by sintering is 2.2.
A method for producing a carbon-based current-collecting sliding material, characterized in that the pressure-molding conditions are set so that the electric resistance is ˜4.0 g / cm ³ , and the electric resistivity is 1,700 μΩcm or less. 2. A metal powder 35-7 having good conductivity in a weight ratio.
A powder material consisting of 0%, boron nitride 0.2 to 8% and the balance carbon powder is mixed, and the mixed powder is temporarily molded with a pressing force of 1 to ² T / cm ² , and the temporary molded body is made of nylon or the like. Vacuum packaging, the vacuum packaging temporary molded body is put into a pressure container, and isotropic pressure of ² to 6 T / cm ² is applied to the temporary molded body through a pressure medium by a cold isostatic pressing method, and the molded body is molded. The compact is sintered in a non-oxidizing atmosphere at a high temperature within the range where metal is not eluted from the compact, and the apparent density of the compact is 2.2 to 4.0 g / cm ³ , and the electrical resistivity is 1,700 μΩcm. A method for producing a carbon-based current-collecting sliding material, characterized in that: 3. A metal powder 35-7 having good conductivity in a weight ratio.
Powder material consisting of 0%, boron nitride 0.2 to 8%, and the balance carbon powder is mixed, and the mixed powder is packed in a rubber mold and sealed,
The mixed powder rubber type sealed body is put into a pressure vessel, and isotropic pressure of ² to 6 T / cm ² is applied to the mixed powder rubber type sealed body through a pressure medium by a cold isostatic pressing method, and then molded. The compact is sintered in a non-oxidizing atmosphere at a high temperature within a range where metal is not eluted from the compact, and the apparent density of the compact is 2.2 to 4.0 g /
cm ³ and electrical resistivity of 1,700 μΩcm or less, a method for producing a carbon-based current-collecting sliding material. 4. A metal powder 35-7 having good conductivity in a weight ratio.
A powder material consisting of 0%, boron nitride 0.2 to 8%, and the balance carbon powder is mixed, and the mixed powder is packed in a mold to 0.5 to 1.
Primary pressurization with a pressing force of 5 T / cm ² and then maintaining the pressurization state in the mold for several tens of seconds to several minutes, then further 2-6 T /
It is molded by applying at least a secondary pressure of cm ² , and the molded body is sintered in a non-oxidizing atmosphere at a high temperature within a range where metal is not eluted from the molded body, and the apparent density of the sintered body is 2.2. ~ 4.
A method for producing a carbon-based current-collecting sliding material, characterized in that the electrical resistance is 0 g / cm ³ and the electrical resistivity is 1,700 μΩcm or less.