JP2014218723A - Copper-based sinter friction material and brake shoe for railway vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper-based sinter friction material with no need of complicated manufacturing processes and advantageous in terms of costs.SOLUTION: A copper-based sinter friction material containing copper and tin contains ferromanganese of 2 to 20 mass%. The copper-based sinter friction material is applicable to a brake shoe for a railway vehicle, an adhesion-improved abrasive material or the like.

Description

  The present invention relates to a copper-based sintered friction material and a railcar brake using the same.

  Japanese Patent Laying-Open No. 2007-309368 (Patent Document 1) describes that a copper-based sintered friction material is mainly used in a railcar brake device. The railcar brake is composed of a copper-based sintered friction material and a steel plate base metal that supports the copper-based sintered friction material.

  The characteristics required as a copper-based sintered friction material are that the wear resistance is good, that the aggressiveness against the mating material is moderate, and that the braking distance during braking can be made relatively short. In order to improve such characteristics, attempts have been made to disperse various substances such as graphite, alumina, silica, molybdenum disulfide, lead, and bismuth in the friction material.

  Among these substances, graphite stabilizes the coefficient of friction and can reduce the wear of the friction material itself and the facing material, but it has poor wettability with copper and copper alloys. There is a possibility that it will easily fall off the friction material body. Alumina and silica contribute to improving the wear resistance of the friction material itself, but are more aggressive against the counterpart material. If molybdenum disulfide is contained in a large amount, the strength of the friction material itself may be reduced. The use of lead and bismuth is restricted in consideration of environmental problems.

  Japanese Patent Laid-Open No. 9-60673 (Patent Document 2) describes a copper-based sintered friction material used for brake lining and the like as a filler in order to have good wear resistance and moderate attack on the facing material. It has been proposed to include 0.2 to 5.0% by volume of titanium and 5 to 15% by volume of graphite powder, and coat a part or all of the surface of the graphite powder with titanium. In this publication, since titanium has good wettability with both graphite and copper, the effect is described that if titanium is attached to the surface of the graphite powder, the graphite is less likely to fall off the friction material body.

JP 2007-309368 A Japanese Patent Laid-Open No. 9-60673

  In order to obtain the friction material disclosed in Japanese Patent Laid-Open No. 9-60673 (Patent Document 2), it is necessary to perform a granulation method or a composite method for coating titanium on the graphite powder surface. Examples of granulation methods include rolling granulation, fluidized bed granulation, stirring granulation, extrusion granulation, disintegration granulation, dissolution granulation and the like. Further, examples of the complexing method include mechanofusion processing, kryptron processing, hybridization processing, and the like. Such a granulation method or compounding method complicates the manufacturing process of the friction material and increases the manufacturing cost of the friction material. In addition, titanium is expensive, and if it is included in a large amount, the cost of the friction material is increased.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a copper-based sintered friction material that does not require a complicated manufacturing process and is advantageous in terms of cost.

  The copper-based sintered friction material according to the present invention contains copper and tin and is characterized by containing 2 to 20% by mass of ferromanganese.

  In a preferred embodiment, the copper content in the copper-based sintered friction material is 55 to 67 mass%, and the tin content is 5 to 7 mass%.

  Further preferably, the copper-based sintered friction material further contains one or more components selected from the group consisting of iron, barium sulfate, graphite, and mullite. In one embodiment, the copper-based sintered friction material contains 5 to 7% by mass of iron, 2 to 3% by mass of barium sulfate, 7 to 10% by mass of graphite, and 3 to 5% by mass of mullite.

  The copper-based sintered friction material may further contain one or more components selected from the group consisting of phosphorus, sulfur, molybdenum disulfide, and potassium titanate.

  The copper-based sintered friction material may contain 0.1 to 1.5% by mass of titanium.

  A railcar brake device according to the present invention includes a steel base metal, a steel reinforcing plate fixed to the steel base metal by welding, copper and tin, and is pressed onto the steel reinforcing plate. And a copper-based sintered friction material joined by sintering. Here, the copper-based sintered friction material contains 2 to 20% by mass of ferromanganese.

  In a preferred embodiment, the copper content in the copper-based sintered friction material is 55 to 67 mass%, and the tin content is 5 to 7 mass%.

  Further, preferably, the copper-based sintered friction material contains 5 to 7% by mass of iron, 2 to 3% by mass of barium sulfate, 7 to 10% by mass of graphite, and 3 to 5% by mass of mullite.

  Ferromanganese is a relatively inexpensive and readily available material. By including an appropriate amount of this ferromanganese in the copper-based sintered friction material, while improving the wear resistance of the friction material itself, the opponent's aggression is eased, and the braking distance during braking is relatively short. Can do.

It is a figure which shows the railcar brake device which is an example of application of this invention. It is a figure which shows the testing machine for evaluating the performance of a copper-type sintered friction material. It is a figure showing the method for measuring the amount of wear of a wheel diagrammatically. It is a figure which shows the relationship between FeMn content and braking distance (stop distance). It is a figure which shows the relationship between FeMn content and friction material wear. It is a figure which shows the relationship between FeMn content and wheel abrasion amount. It is a figure which shows the relationship between the weight part of Cu and the friction material wear amount. It is a figure which shows the relationship between the weight part of Cu, and the amount of wheel wear. It is a figure which shows the relationship between the weight part number of Cu, and a stop distance (braking distance). It is a figure which shows the relationship between content of Ti, and friction material wear amount. It is a figure which shows the relationship between content of Ti, and wheel abrasion amount.

  FIG. 1 shows a railcar brake device which is one application example of the present invention. First, with reference to FIG. 1, the structure of a railcar brake device will be described.

  The railcar brake 10 is joined to a steel base 11 formed in an arc shape, a steel reinforcing plate 13 fixed to the steel base 11 by welding, and pressure sintering on the reinforcing plate 13. The copper-based sintered friction material 14 is provided. The steel base 11 has an attachment portion 12 that is loosely fitted in a recess of a brake head attached to the vehicle side.

  The copper-based sintered friction material 14 contains copper and tin as main components. A feature of the present invention is that the copper-based sintered friction material 14 contains a predetermined amount of ferromanganese. Ferromanganese is a material that is inexpensive and easily available compared to titanium and the like. The inventor of the present application has found through experiments that the properties of the copper-based sintered friction material can be improved if a predetermined amount of ferromanganese is contained. This point will be described in detail below.

[Ferromanganese]
Ferromanganese (FeMn) is an alloy of manganese and iron, and there are various types. JIS G2301 “ferromanganese” describes the following types.

  The present inventor used high-carbon ferromanganese in the experiments described below, but similar effects are expected even when medium-carbon ferromanganese and low-carbon ferromanganese are used.

[Ingredient materials and blending ratio]
Sample numbers 1 to 18 of component materials and blending ratios shown in Table 2 below were prepared. Sample Nos. 1 to 11 were obtained by keeping the weight parts of copper, tin, iron, barium sulfate, graphite and mullite constant and gradually changing the addition amount of ferromanganese (FeMn) between 0 and 30 parts by weight. It is. Sample Nos. 12 to 16 are obtained by making the weight parts of copper, tin, iron, barium sulfate, graphite and mullite constant and gradually changing the content of titanium (Ti) between 0.1 and 2. is there. In Sample Nos. 17 and 18, the weight parts of tin, iron, barium sulfate, graphite, mullite, and ferron manganese were made constant, and the copper content was 60 parts by weight and 80 parts by weight.

  Table 2 shows the content in parts by weight. Table 3 below shows the content of Table 2 in mass%.

[Manufacture of copper-based sintered friction material]
The starting materials were mixed under the following conditions.

a) A mixer V-type mixer was used.

b) Mixing time The starting material powder was put into a V-shaped mixer and mixed for about 20 minutes.

c) Compaction conditions Molded product dimensions: 100 mm x 37 mm rectangular bottom surface with a height of 40 mm.

Molding pressure: 4 ton / cm ²
Molding ton number: 148 ton
Pressurization time: 10 seconds

d) Sintering conditions The temperature was raised to 350 ° C. in a vacuum sintering furnace and kept at this temperature for 30 minutes to remove the oil. Thereafter, the temperature was raised to 900 ° C. over 30 minutes (temperature increase rate: 18.3 ° C./min) and held at this temperature for 60 minutes. Thereafter, the temperature was lowered to 50 ° C.

[Tester and test conditions]
The performance of the copper-based sintered friction material was evaluated using the testing machine shown in FIG. The testing machine includes a wheel 1, a friction material 2 (copper-based sintered friction material), a pressing device 3, a boat body 4, a load cell 5, an inertial body 6, and a motor 7.

  The test conditions are as follows.

Initial braking speed: 70 km / h
Wheel diameter: 400mm
Friction material pressing force: 3.8 kN
Equivalent moment of inertia: 39.2 kg · m ²
Number of tests: 50 times The friction material was pressed from a braking initial speed of 70 km / h, and the test was stopped 50 times (stopping wheel rotation), and one test was performed 50 times for each sample.

[Characteristic measurement method]
Friction material (copper-based sintered friction material) wear amount: calculated by mass difference before and after the test.

  Wheel wear amount: Measured using a small roughness measuring device (surf-order SE500 manufactured by Kosaka Laboratory). Specifically, the following procedure was used. FIG. 3 schematically shows the measurement method.

  1) Obtain a cross-sectional curve in the wheel axis direction before the test.

  2) Obtain a cross-sectional curve in the wheel axis direction after the test.

  3) The above two curves are overlapped, and the difference in shape is shown.

  4) Differences were read at regular intervals.

  Braking distance: πx wheel diameter x wheel rotation speed was measured with a tester measurement system. The wheel rotation speed is the cumulative number from the start to the stop of the brake.

[Characteristic comparison by FeMn content]
Table 4 below shows the friction material characteristics of sample numbers 1 to 11 in which the content of ferromanganese (FeMn) was changed from 0 to 30 parts by weight.

  FIG. 4 shows the relationship between the FeMn content and the braking distance (stop distance), FIG. 5 shows the relationship between the FeMn content and the friction material wear amount, and FIG. 6 shows the relationship between the FeMn content and the wheel wear amount. Show.

  As shown in FIG. 4, when the FeMn content is 0 to 25 parts by weight, the stopping distance is about 250 m, and there is not much difference, but when it is 30 parts by weight, the stopping distance is close to 350 m and the braking performance is reduced. It was seen. From the viewpoint of braking performance, the content of FeMn is preferably 25 parts by weight or less.

  As shown in FIG. 5, the friction material wear amount exceeded 1.50 g when the content of FeMn was 0 to 1 part by weight. It became 1.00 g or less. From the viewpoint of wear resistance of the copper-based sintered friction material, the FeMn content is preferably 3 parts by weight or more.

  As shown in FIG. 6, when the content of FeMn is 0, the wear amount of the wheel is as large as 1.5 μm, and it is recognized that the opponent attack is active. When the content of FeMn is 0.5 parts by weight or more, it is recognized that the wheel wear amount is as small as 0.8 μm or less, and the opponent attack is mitigated.

  From the above results, it is recognized that the preferable content of FeMn for improving the properties of the copper-based sintered friction material in a balanced manner is 3 to 25 parts by weight. When this weight part is converted into mass%, it becomes 2.9 to 19.7 mass%. Therefore, the preferable FeMn content is 2 to 20% by mass with respect to the entire copper-based sintered friction material.

[Characteristic comparison of change in number of parts by weight of Cu in 7 parts by weight of FeMn]
The friction material characteristics were compared when FeMn was 7 parts by weight and the Cu content was 60 parts by weight (sample number 17), 70 parts by weight (sample number 6), and 80 parts by weight (sample number 18). The results are shown in Table 5 below.

  FIG. 7 shows the relationship between the number of parts by weight of Cu and the friction material wear amount, FIG. 8 shows the relationship between the number of parts by weight of Cu and the amount of wheel wear, and the relationship between the number of parts by weight of Cu and the stopping distance (braking distance). As shown in FIG.

  As shown in FIG. 7, when the weight part of Cu is 70 or less, the friction material wear amount is as small as about 0.70 g, but when it is 80 parts by weight, the friction material wear amount is increased to about 1.20 g. It is recognized that From the viewpoint of wear resistance of the copper-based sintered friction material, the weight part of Cu is desirably 75 or less.

  As shown in FIG. 8, when the weight part of Cu is 60 to 80, it is recognized that the wheel wear amount is kept as low as about 0.40 μm.

  As shown in FIG. 9, the stopping distance (braking distance) is 300 m or less if the weight part of Cu is 70 or less, but becomes nearly 400 m when the weight part is 80 parts by weight, resulting in a reduction in braking performance. From the viewpoint of braking performance, it is desirable that the number of parts by weight of Cu is 75 or less.

  From the above results, it is recognized that the copper content in the copper-based sintered friction material containing 7 parts by weight of ferromanganese is desirably about 75 parts by weight or less.

[Characteristic comparison regarding Ti content]
The characteristics of the copper-based sintered friction material when titanium (Ti) was contained without containing ferromanganese were evaluated. Table 6 shows the friction material characteristics of Sample Nos. 1 and 12 to 16 in which Ti is gradually changed between 0 and 2 parts by weight.

  FIG. 10 shows the relationship between the Ti content (parts by weight) and the friction material wear amount, and FIG. 11 shows the relationship between the Ti content (parts by weight) and the wheel wear amount.

  As shown in FIG. 10, the friction material wear amount of Sample No. 1 containing no Ti is about 2 g, and it is recognized that the wear resistance is inferior. If the Ti content is 0.1 to 1 part by weight, the friction material wear amount is 1.5 g or less, and the wear resistance is improved. When the Ti content is 2 parts by weight, the friction material wear amount exceeds 1.5 g, and the wear resistance decreases.

  As shown in FIG. 11, when the Ti content is 0, the wheel wear amount is 1.5 μm, and it is recognized that the opponent is aggressive. When the Ti content is 0.1 parts by weight or more, the wheel wear amount is 1 μm or less, and it is recognized that the opponent attack is mitigated.

  From the results shown in FIGS. 10 and 11, it is recognized that the preferable Ti content is 0.1 to 1.5 parts by weight. A preferable Ti content is 0.1-1.5 mass% when the weight part is converted by mass%.

[Preferred component substances and their amounts]
In order to improve the characteristics of the copper-based sintered friction material, in addition to containing a predetermined amount of ferromanganese, another material may be contained. As described above, the inclusion of 0.1 to 1.5% by mass of titanium improves the wear resistance of the friction material and relaxes the opponent attack. Therefore, by including titanium together with ferromanganese, the characteristics of the copper-based sintered friction material can be improved.

  As shown in sample numbers 2 to 11, the copper-based sintered friction material is one or more selected from the group consisting of iron, barium sulfate, graphite, and mullite in addition to copper, tin, and ferromanganese. These components may be contained. Sample numbers 2-11 contain all these substances. Preferable content is iron 5-7 mass%, barium sulfate 2-3 mass%, graphite 7-10 mass%, and mullite 3-5 mass%.

  Iron contributes to the improvement of the frictional force and the wear resistance of the friction material. Barium sulfate contributes to improving the heat resistance of friction materials and reducing costs. Graphite contributes to improving the lubricity of the friction material and mitigating opponent attack. Mullite contributes to improving the wear resistance of the friction material.

  As components other than those described above, one or more components selected from the group consisting of phosphorus, sulfur, molybdenum disulfide and potassium titanate may be contained. Phosphorus contributes to improving the physical properties of the friction material. Sulfur contributes to improving the lubricity of the friction material. Molybdenum disulfide contributes to improving the lubricity of the friction material. Potassium titanate contributes to improving the wear resistance of the friction material and mitigating the opponent attack.

  The present invention can be advantageously used as a copper-based sintered friction material and a railcar brake using the copper-based sintered friction material. Furthermore, the present invention can be applied to a thickened adhesive abrasive.

  DESCRIPTION OF SYMBOLS 1 Wheel, 2 Friction material, 3 Pushing device, 4 Ship body, 5 Load cell, 6 Inertial body, 7 Motor, 10 Railway vehicle control, 11 Steel base metal, 12 Mounting part, 13 Steel reinforcement board, 14 Copper Sintered friction material.

Claims (9)

In copper-based sintered friction materials containing copper and tin,
A copper-based sintered friction material comprising 2 to 20% by mass of ferromanganese. The copper-based sintered friction material according to claim 1, wherein the copper content is 55 to 67 mass% and the tin content is 5 to 7 mass%. The copper-based sintered friction material according to claim 1 or 2, comprising one or more components selected from the group consisting of iron, barium sulfate, graphite, and mullite. The copper-based sintered friction material according to any one of claims 1 to 3, comprising one or more components selected from the group consisting of phosphorus, sulfur, molybdenum disulfide, and potassium titanate. The copper-based sintered friction material according to claim 1 or 2, comprising 5 to 7% by mass of iron, 2 to 3% by mass of barium sulfate, 7 to 10% by mass of graphite, and 3 to 5% by mass of mullite. The copper-based sintered friction material according to any one of claims 1 to 5, comprising 0.1 to 1.5% by mass of titanium. A steel base metal, a steel reinforcing plate fixed to the steel base metal by welding, a copper-based sintered friction material containing copper and tin, and joined by pressure sintering on the steel reinforcing plate; In a railcar brake device equipped with
The copper-based sintered friction material contains 2 to 20% by mass of ferromanganese. The rolling stock for a railway vehicle according to claim 7, wherein the copper-based sintered friction material has a copper content of 55 to 67 mass% and a tin content of 5 to 7 mass%. The said copper-based sintered friction material contains 5-7 mass% of iron, 2-3 mass% of barium sulfate, 7-10 mass% of graphite, and 3-5 mass% of mullite. The railcar brake device described.

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