JP5512323B2 - Vehicle brake and brake block for brake - Google Patents

Description

  The present invention relates to a vehicle restrictor and a brake block for a restrictor.

  There are two types of brake systems for railway vehicles: the disc method and the tread method (controls), and the tread method is adopted for conventional lines except for some high-speed vehicles. Examples of the brake used for the tread method include a caster made of alloy cast iron in a ceramic block in addition to alloy cast iron, synthetic (phenolic resin), sintered metal, and the like (Patent Document 1). The cast iron control device can stably obtain the adhesive force between the wheels / rails by appropriately expressing the wheel tread. Therefore, it is not easily affected by rain and snow, and further has a low aggressiveness to wheels (temperature rise and wear), so it is used in cold regions with a lot of snow such as Hokkaido.

  Up to now, cast iron brakes have been developed to improve friction characteristics and wear resistance by adding alloying elements such as phosphorus, chromium, molybdenum, boron, etc. to ordinary iron, and have responded to higher speeds. It was. It has been clarified that the intervention of silicon carbide ceramics at the frictional interface with the wheel is effective in improving the friction coefficient of the alloy cast iron brake (References 1 to 3, Non-Patent Reference 1). For example, a brake element for vehicle brakes has been proposed in which ceramic particles are molded into a block shape in advance and embedded in a cast iron brake, so that the ceramic block functions to supply ceramic particles to the friction surface during braking. (Patent Document 1). In addition, it has been proposed to use a ceramic porous block for the purpose of improving the yield in mass production and preventing chipping due to cracks (Patent Documents 2 to 3, Non-Patent Document 1).

JP-A-7-103267 Japanese Patent Laid-Open No. 10-30661 JP 2001-246455 A

RTRI REPORT Vol. 22, no. 4, Apr. 2008 p17-22. "Development of cast iron composite control with excellent friction characteristics"

Silicon carbide ceramics have been used as brake blocks used in conventional cast iron brakes. However, when such ceramics are used, high frictional properties can be obtained, but aggressiveness to wheels (wear, thermal load) is high. There was a problem of becoming.
In order to solve the above-described problems, an object of the present invention is to provide a braking block and a vehicle brake member that have high friction characteristics and are less aggressive to wheels.

The present invention (1) includes a cast iron brake body having a braking friction surface (for example, the brake body 110),
In the vehicle brake member, including a brake block (for example, the brake block 120) that is embedded in the main body of the brake member and a part of which is exposed to the braking friction surface.
A braking device for a vehicle (for example, a braking device 100), wherein the braking block contains alumina and aluminum phosphate.

  The present invention (2) is the vehicle restrictor for the invention (1), wherein the cast iron is alloy cast iron.

  The present invention (3) is the vehicle brake device according to the invention (2), wherein the alloy cast iron contains phosphorus.

  The present invention (4) is the vehicle brake member according to any one of the inventions (1) to (3), wherein the braking block is a porous block.

  The present invention (5) is the vehicle brake member according to any one of the inventions (1) to (4), wherein the braking block contains carbon nanotubes.

The present invention (6) is a brake block for a brake wheel disposed on a braking friction surface of a vehicle wheel brake,
The brake block is a brake block for a brake wheel, characterized in that the brake block contains alumina and aluminum phosphate.

  The present invention (7) is the brake block for a brake wheel according to the invention (6), wherein the brake block is a porous block.

  The present invention (8) is the brake block for a brake wheel according to the invention (6) or (7), wherein the brake block contains carbon nanotubes.

  According to the brake according to the present invention, the effect of improving the friction coefficient and reducing the amount of wear is exhibited as compared with SiC that has been conventionally used as a braking block. The control device according to the present invention has the property of exhibiting excellent friction characteristics and wear characteristics, particularly at high speeds. In addition, according to the control device according to the present invention, an increase in wheel temperature can be suppressed, so that an effect of contributing to an improvement in crack resistance of the wheel is achieved.

  In the case of using an alloy cast iron, conventionally, phosphorus, chromium, or the like is added to the alloy cast iron, thereby generating a hard phase (steadite or cementite) derived therefrom and improving the friction coefficient. However, the presence of a large amount of hard phase due to the addition of phosphorus or the like makes the material brittle and easily causes thermal cracks, so rare metals such as molybdenum and nickel have been used to densify the cast iron base (pearlite). It was. On the other hand, according to the control device according to the present invention, since it has an effect of improving the friction coefficient, it is possible to reduce the amount of phosphorus added to the alloy cast iron, and accordingly, the amount of the rare metal added is also increased. Since it can be reduced, it becomes possible to obtain a low-cost control device. In addition to the above, molybdenum, chromium, and manganese have an effect of promoting cementite as a free carbide, and stabilize the friction characteristics as a hard phase in a high temperature range replacing a steadite that melts at a low melting point. In the present invention, since the elution of the steadite phase can be prevented, the precipitation of free carbide itself can be reduced, so that the amount of molybdenum or chromium added can be suppressed.

FIG. 1 is a schematic configuration diagram of a control device according to the present invention, where (a) is a front view and (b) is a side sectional view. FIG. 2 is a photograph showing a state before and after application of the coating agent for the alumina porous block used in the examples. FIG. 3 is a photograph of the control used in the example. FIG. 4 is a diagram illustrating a measurement result of the braking distance in the braking test. FIG. 5 is a diagram showing measurement results of the wear amount in the braking test. FIG. 6 is a diagram showing the measurement results of the wheel temperature in the braking test. FIG. 7 is a diagram illustrating a measurement result of the brake wheel temperature in the braking test. FIG. 8 is a diagram showing the measurement result of the average friction coefficient in the braking test.

  A brake according to the present invention includes a brake iron body made of cast iron having a braking friction surface, and a braking block embedded in the brake wheel main body and partially exposed to the braking friction surface. It is a ring child. The present invention is characterized in that the braking block contains alumina. That is, by selecting alumina as the ceramic material for the brake block, it is possible to provide a brake device having excellent friction characteristics and low wheel attack.

Brake shoes Figure 1 is a schematic configuration diagram of a brake shoe according to the present invention, (a) is a front view, (b) shows a side cross-sectional view. The brake member 100 includes a cast iron brake wheel main body 110 having a braking friction surface 111 and a braking block 120 that is partially exposed to the braking friction surface. The brake body 110 has an arcuate curved shape, and the inner surface side of the arc is a braking friction surface 111. On the other hand, a cotter portion 113 is provided on the outer surface side.

  A back metal 130 is provided in the restrictor body 110 so as to be located behind the brake block and cast into the restrictor body. The back metal 130 includes a plate-like body 131 having a curvature similar to that of the main body of the brake control body and a connecting body 132 positioned in the cotter portion. The back metal is provided to prevent crack breakage of the cast iron control ring main body 110. Further, it is used for fixing a brake block guide in a method for manufacturing a brake device described later.

  The material of the brake control body 110 is not particularly limited, but may include alloy cast iron obtained by adding alloy elements such as phosphorus, chromium, molybdenum, and nickel to normal cast iron in consideration of heat resistance, wear resistance, and the like.

The alloy cast iron in the present invention is preferably a combination of pearlite matrix and flake graphite, in which free carbides such as steadite (ternary eutectic structure of Fe + Fe ₃ C + Fe ₃ P) and cementite are dispersed and precipitated. . Here, flake graphite plays a role as a lubricant.

  It is preferable to add the above alloy elements to the perlite base. Among these alloy elements, it is preferable to add phosphorus. By adding phosphorus, steadite, which is a hard substance, can be generated in the alloy cast iron. The addition amount of phosphorus is preferably 0.3% by mass or more and preferably 1.5% by mass or more in the alloy cast iron. Although an upper limit is not specifically limited, For example, it is 2.5 mass% or less.

  In addition, it is preferable to add molybdenum (Mo) or nickel (Ni). By adding these rare metals, the pearlite matrix can be densified. However, by using the braking block of the present invention, it is not necessary to generate a large amount of a hard phase that makes the control wheel brittle, so the amount of these rare metals added can be reduced.

  The brake block 120 is embedded in the brake body 110 so that a part of the brake block 120 is exposed to the braking friction surface. It is preferable to use a porous block as the braking block, and it is preferable that the porous block is integrated by casting the entire block including the inside of the gap by the control body. Although the shape of the porous block 120 is not specifically limited, For example, it is suitable that it is formed in the column shape. Thereby, at the time of manufacture mentioned later, when molten cast iron is poured into a model and a block floats, there is an effect that a formwork is not broken.

  The braking block according to the present invention contains alumina. The braking block according to the present invention is preferably a porous block, and more specifically, the main component of the skeleton forming the porous block is preferably alumina. In addition, a main component means the component containing 50 mass% or more here.

  The alumina used in the present invention is not particularly limited. For example, α-alumina can be used. It is also preferable to use easily sinterable alumina. Here, it is preferable that the easily sinterable alumina is low soda alumina. Here, low soda alumina means alumina having a soda content of 0.10% by mass or less with respect to alumina. Here, the measuring method for the soda is according to JIS R9301-9-9: 1999. When alumina contains a large amount of soda, crystal growth during sintering becomes non-uniform, which adversely affects the sintered bulk density.

The thermal conductivity of alumina is preferably 15 to 40 J / m · sec · ° C. The thermal conductivity is measured by the method specified in JIS R1611. The thermal expansion coefficient of alumina is preferably 5.0 to 9.0 × 10 ⁻⁶ / ° C. The thermal expansion coefficient is measured by the method specified in JIS R1618. Moreover, it is suitable that the Vickers hardness of alumina is 1.2 to 2.5 × 10 ⁴ MPa. Vickers hardness is measured according to JIS C2141.

The material of the skeleton of the ceramic porous body according to the present invention preferably contains aluminum phosphate in addition to the alumina. By containing the aluminum phosphate, the efficiency of supplying alumina particles to the wheels is increased, so that an excellent braking distance and a low wheel attack property are exhibited. Here, specifically, the aluminum phosphate includes a primary aluminum phosphate binder represented by a formula of Al ₂ O ₃ .3P ₂ O ₅ .6H ₂ O. At this time, the Al ₂ O ₃ component is preferably 5 to 10%, and the P ₂ O ₅ component is preferably 25 to 65%. In addition, as for content of the aluminum phosphate in the slurry at the time of manufacture, 3-30 mass parts is suitable with respect to 100 mass parts of alumina, 6-25 mass parts is more suitable, 9-20 mass parts Is more preferred. In the material for forming the skeleton of the ceramic porous body (final product) according to the present invention, the P ₂ O ₅ component is preferably 2 to 20% by mass, more preferably 5 to 15% by mass, 7-13 mass% is still more suitable.

  In addition, as optional components, clays such as talc and clay, and nanocarbons such as carbon nanotubes may be contained. Although it does not specifically limit as content of a talc, 0.1-10 mass parts is suitable with respect to 100 mass parts of alumina. As content of clay, 0.1-10 mass parts is suitable with respect to 100 mass parts of alumina.

  Among the optional components, it is preferable that carbon nanotubes are included. In the case of a porous block, the material of the skeleton preferably contains carbon nanotubes. By containing the carbon nanotube, the thermal conductivity is increased, and therefore the wheel temperature can be kept lower, so that the attacking ability to the wheel is lowered. Moreover, since the uniformity of thermal conductivity is increased by containing carbon nanotubes, heat spots are less likely to occur. As content of a carbon nanotube, 0.01-30 mass parts is suitable with respect to 100 mass parts of alumina, 0.05-20 mass parts is more suitable, 0.1-10 mass parts is further Is preferred.

  The ceramic porous block preferably has open cells. 5-30 ppi is suitable for the porosity of a ceramic porous block, 7-25 ppi is more suitable, and 10-20 ppi is still more suitable.

  Although the manufacturing method of a porous block is not specifically limited here, For example, it can manufacture through an impregnation process, a drying process, a degreasing process, and a sintering process.

  The impregnation step is a step of impregnating the organic porous body with a slurry in which a ceramic material forming the skeleton of the porous block is dispersed or dissolved. In this process, it is preferable to use a polyurethane foam as the organic porous body.

  In the drying step, after the impregnation step, the solvent of the impregnated slurry is removed. Here, the adhering amount of the ceramic material slurry to the organic porous body is preferably about 1000 to 2500 parts by mass with respect to 100 parts by mass of the organic porous body.

  In the degreasing process, after the drying process, the organic porous body coated with the material is heated to remove the skeleton of the porous body.

  Finally, in the sintering step, the porous material after the degreasing step is sintered to obtain the ceramic porous block according to the present invention. In addition, a sintering process may be performed continuously with the said degreasing process.

  Then, the manufacturing method of the control device concerning this invention is demonstrated. The control device according to the present invention can be manufactured using a mold composed of an upper mold and a lower mold. First, a back metal having a block guide in a lower mold is placed with the block guide facing the upper surface, and the braking block is fixed to the block guide. Here, the block guide is, for example, a rod-shaped protrusion protruding from the back metal toward the braking friction surface. Moreover, the hole for letting a guide pass along the shape of the said rod-shaped protrusion may be provided in the center of the braking block. Next, the upper mold is brought into contact with the lower mold, and molten cast iron is poured into the mold. Then, each braking block floats due to the difference in specific gravity from the molten cast iron, and one side surface thereof comes into contact with the braking friction surface. When a ceramic porous block is used as the braking block, the molten cast iron flows into the pores of the porous block in this state, and the porous block and the cast iron are integrated. Then, by cooling the molten cast iron, the main body of the brake member in which the back metal and the braking block are cast is solidified, and the brake member according to the present invention is manufactured.

When a porous block is used as the brake block, a coating agent may be applied to the porous block before pouring molten cast iron. By applying the coating agent, the porous block can be prevented from collapsing. Here, the coating agent is not particularly limited as long as it is a cast iron coating agent, and examples thereof include MgO.SiO ₂ and zircon coating agents.

  The control device according to the present invention can be used as a control device for a vehicle such as a railway, and the braking friction surface of the control device is pressed against a wheel to brake the vehicle. The control device according to the present invention has the above-described configuration, and is manufactured by the above-described manufacturing method, so that when the ceramic porous block is used, the block is controlled in a state where each pore is filled with cast iron. The wheel body can be integrated. Therefore, since the ceramic porous block is exposed to the braking friction surface of the control member in a state of being uniformly dispersed in a state of being integrated with cast iron, when the control member is pressed against the wheel, the ceramic porous block is The wheel can be pressed against the wheel on average, and ceramics are sequentially and quantitatively supplied to the frictional interface with the wheel.

Example 1 (Production of alumina porous block)
In accordance with the blending ratio in Table 1 below, alumina (Showa Denko, AL-170, Na ₂ O content: 0.04%, thermal conductivity: 36 J / m · sec · ° C., thermal expansion coefficient: C‖6. ^{6 × 10 -6 /℃,C⊥5.3×10 -6 / ℃} , Vickers hardness: 2.2 × ¹⁰ 4 MPa) and gairome clay (KCM Co., gairome clay grade powder KH), Talc (manufactured by Maruo Calcium Co., PKP # 80) is mixed and aluminum phosphate solution {manufactured by Taki Chemical, 50 L (P ₂ O ₅ component: 31.0 ± 1.0%, Al ₂ O ₃ component: 7 3 ± 0.5%, dry solid content 33%)} and mixed in a mortar. The slurry thus obtained was impregnated into a ski sample with a polyurethane foam (manufactured by Inoac Corporation, MF-7) having a sample size of Φ65 mm and a thickness of 22 mm. Here, the amount of attachment was 35 g per sample. Subsequently, after drying at 50 ° C., heating at a temperature increase rate of 25 to 600 ° C. and 50 ° C./h, followed by heating at a temperature increase rate of 600 to 1500 ° C. and 200 ° C./h, The degreasing and sintering steps were performed in an oxygen atmosphere by maintaining the time. Then, it returned to normal temperature by natural cooling. Thereby, the alumina porous block was able to be obtained. Here, the porosity of the obtained alumina porous block was 10 ppi. Moreover, the composition of the obtained alumina porous block was measured by fluorescent X-ray analysis. For comparison, the composition of the silicon carbide ceramic porous block used in the braking test described later was also measured by fluorescent X-ray analysis.

In addition, a coating agent {Okasuper 750B (MgO · SiO ₂ system)} was applied to the resulting alumina porous block after the production for the production of the control wheel. The photographs before and after applying the coating agent to the produced alumina porous block are shown in FIG.

Example 2 (Manufacture of control wheel)
An alloy cast iron control device in which two alumina porous blocks of Example 1 were cast was manufactured. The composition of the alloy cast iron used here was C: 3.46, Si: 2.22, Mn: 1.20, P: 1.86, S: 0.015, Cu: 0.79, Ni: 0.00. 51, Cr: 0.50, Mo: 1.01. A photograph of the manufactured alloy cast iron brake is shown in FIG.
In addition, the alloy cast iron control element which does not contain the ceramic porous block in the braking test mentioned later and the alloy cast iron control element which casts the silicon carbide ceramic porous block used the alloy cast iron of the same component.

It was carried out full-scale brake tested for braking test above the cast iron system Waco. In this test machine, the two brake elements are pressed from the left and right when a wheel with a moment of inertia equivalent to that of an actual vehicle is rotating at a predetermined speed, and various properties are measured until the brake stops. Each measurement was performed 5 times. Table 3 shows the test conditions. Note that the test was performed in part according to the procedure of “JIS E 7501 Performance Test and Inspection Method for Cast Iron Controls for Railway Vehicles”.

(Braking distance)
The alloy cast iron control ring of Example 2 above, the alloy cast iron control ring not including the ceramic porous block, and the alloy cast iron control ring formed by casting the silicon carbide ceramic porous block were prepared, and the braking test was performed. The distance from the predetermined initial brake speed until the wheel was stopped after braking was measured. The average result of 5 times is shown in Table 4. Further, FIG. 4 shows a graph of the average braking distance of each control member under the condition of an initial speed of 135 km / h.

(Abrasion amount)
The alloy cast iron control ring of Example 2 above, the alloy cast iron control ring not including the ceramic porous block, and the alloy cast iron control ring formed by casting the silicon carbide ceramic porous block were prepared, and the wear test was performed. The amount of wear per unit control was measured for each operation of stopping the vehicle by applying a brake from a predetermined initial brake speed. The average result of 5 times is shown in Table 5. Further, FIG. 5 shows a graph of the average amount of wear of each control member under the condition of an initial speed of 135 km / h.

(Wheel temperature)
The alloy cast iron brake of Example 2 above, an alloy cast iron brake without a ceramic porous block, and an alloy cast iron brake made of a silicon carbide ceramic porous block were prepared, and a wheel temperature test was performed. . The wheel temperature when the vehicle was stopped by applying a brake from a predetermined initial brake speed was measured. The wheel temperature was measured at a position of 10 mm, 40 mm, 70 mm from the outer surface (on the opposite flange side) and a depth of 10 mm from the tread surface. Table 6 shows the average results of the five highest temperatures. Further, the maximum temperature of the wheel under the condition of the initial speed of 135 km / h is graphed and shown in FIG.

(Controlling temperature)
Prepare the alloy cast iron brake of Example 2 above, an alloy cast iron brake without a ceramic porous block, and an alloy cast iron brake with a silicon carbide ceramic porous block cast, and conduct a brake temperature test. It was. The temperature of the two left and right brake members when the vehicle was stopped by applying a brake from a predetermined initial brake speed was measured. The temperature was measured at a distance of 40 mm from the approach end face of the control wheel and a depth of 10 mm from the friction surface. Table 7 shows the average results of the five highest temperatures. In addition, the maximum temperature of the brake member under the condition of the initial speed of 135 km / h is graphed and shown in FIG.

(Average friction coefficient)
The average coefficient of friction f _m, based on the above test results were calculated by the following equation (1).

Here, M: Equivalent wheel load M = I / ^{R 2} (here, I: moment of inertia kg · ^m 2, R: wheel radius m), _{V o} is the brake initial velocity (m / s), L is a brake stop The distance (m) and P are the total pressing force (N) of the control device. The result is shown in FIG.

DESCRIPTION OF SYMBOLS 100: Control wheel 110: Control wheel main body 111: Braking friction surface 113: Cotter part 120: Braking block 130: Back metal 131: Plate-shaped body 132: Connection body

Claims (8)

A control body made of cast iron having a braking friction surface;
In the vehicle brake, which is embedded in the main body of the brake and has a braking block that is partially exposed to the braking friction surface.
The brake device for a vehicle, wherein the brake block contains alumina and aluminum phosphate.   The vehicle control device according to claim 1, wherein the cast iron is alloy cast iron.   3. The vehicle brake according to claim 2, wherein the alloy cast iron contains phosphorus.   The vehicle brake according to any one of claims 1 to 3, wherein the braking block is a porous block.   The vehicle brake according to any one of claims 1 to 4, wherein the braking block contains carbon nanotubes. In the brake block for a brake wheel disposed on the braking friction surface of the vehicle brake wheel,
The brake block for a brake wheel, wherein the brake block contains alumina and aluminum phosphate.   The brake block for a brake wheel according to claim 6, wherein the brake block is a porous block.   The brake block for a brake wheel according to claim 6 or 7, wherein the brake block contains carbon nanotubes.