JP5723669B2 - Brake disc and manufacturing method thereof - Google Patents

Description

  The present invention relates to a brake disc having a friction surface against which a brake pad is pressed, and a brake disc capable of suppressing the friction surface from being cracked or deformed by heat generated during braking, and a method for manufacturing the brake disc.

  Brake discs for obtaining braking force by pressing brake pads are provided on the wheels and axles of railway vehicles such as Shinkansen. Here, this brake disc has a problem that cracks and deformation are caused by the influence of heat generated during braking. Therefore, a brake disk that can suppress the occurrence of cracks and deformation due to brake heat by covering the surface of the disk base material with a material having excellent heat resistance has been proposed (see, for example, Patent Document 1).

  In Patent Document 1, an uneven surface-roughened layer is formed by first blasting the surface of a disk base material, that is, by spraying particles made of an inorganic material at a predetermined pressure. Then, a heat resistant coating layer is formed on the roughened layer via a metal bonding layer. This heat resistant coating layer is obtained by spraying ceramics such as zirconia having excellent heat resistance and toughness on the surface of the metal bonding layer. According to such a configuration, transmission of heat generated at the time of braking to the disk base material is reduced by the heat-resistant coating layer, so that occurrence of cracks and deformation in the disk base material is suppressed.

JP 2009-63072 A

  However, in the conventional brake disc described in Patent Document 1, there is a fear that the adhesion strength between the disc base material and the heat-resistant coating layer is insufficient in a brake environment during high-speed running. That is, by subjecting the surface of the disk base material to blasting, the adhesion strength of the metal bonding layer and the heat-resistant coating layer to the disk base material is improved to some extent. However, there is a need for a heat-resistant coating layer that ensures sufficient adhesion strength to the disk base material without cracking or deformation even in a braking environment during high-speed driving (high-speed rotation, high vibration load, high temperature). The

  The present invention has been made in consideration of such circumstances, and its purpose is to ensure sufficient adhesion strength with the disk base material without causing cracks or deformation even in a braking environment during high-speed traveling. It is to provide means that make it possible to do.

  In order to achieve the above object, the present invention employs the following means. That is, the brake disc according to the present invention is a brake disc that brakes the rotation of the axle when the brake pad is pressed against the surface, and a disc base material that is attached to a rotating body that rotates integrally with the axle, And a built-up layer in which particles of a high melting point metal having a melting point higher than that of the disk base material are dispersed in a matrix material.

  According to such a configuration, since the build-up layer containing the refractory metal is laminated on the surface of the disk base material, the heat generated when the brake pad is pressed against the brake disc is generated by the build-up layer. The presence reduces transmission to the disk base material. Therefore, it is possible to suppress the occurrence of cracks and deformation on the surface of the disk base material due to the influence of heat during braking.

  The brake disk according to the present invention is characterized in that the build-up layer is laminated on the surface of the disk base material by powder build-up plasma arc welding.

  According to such a configuration, the build-up layer is laminated on the surface of the disk base material by powder build-up plasma arc welding. Therefore, at the interface between the build-up layer and the surface of the disk base material, Sufficient adhesion strength is ensured.

  Moreover, the brake disk according to the present invention is characterized in that the build-up layer is laminated over two or more layers on the surface of the disk base material.

  According to such a configuration, when the first build-up layer is laminated on the surface of the disk base material by powder build-up plasma arc welding, a hardened layer is generated by high heat during welding. The base material is cured. However, when the second and third build-up layers are subsequently laminated, the heat during welding is transferred to the disk base material via the first and second build-up layers. The amount of heat is reduced. Therefore, the hardened disk base material is toughened by being tempered by the heat applied during the lamination of the second and third overlay layers. Is granted. Thereby, it can suppress that a crack and a deformation | transformation generate | occur | produce in a disk base material.

  In the brake disc according to the present invention, the refractory metal contains one or more of molybdenum, tungsten, niobium, and tantalum.

  According to such a configuration, the high melting point metal remains as metal particles after welding due to its high melting point, and imparts high heat resistance to the disk base material.

  In the brake disk according to the present invention, the build-up layer contains the refractory metal in a weight ratio of 50% to 80%.

  According to such a configuration, the refractory metal remains as metal particles in an appropriate amount after welding, and imparts high heat resistance to the disk base material.

  In the brake disk according to the present invention, the high melting point metal has particles having an average particle diameter of 75 μm or more and 100 μm or less occupying 70% or more and 80% or less of the total number of particles, and an average particle diameter of 10 μm or more and 45 μm or less. It is characterized in that the particles occupy the rest.

  According to such a configuration, the refractory metal remains as metal particles to impart high heat resistance to the disk base material, and cracks are unlikely to occur in the built-up layer after welding.

  The brake disk according to the present invention is characterized in that the matrix material is made of a nickel-based alloy.

  According to such a configuration, the matrix material made of the nickel-based alloy uniformly bonds the refractory metal, so that the refractory metal is uniformly distributed in the built-up layer. Thereby, it can prevent beforehand that a crack and a deformation | transformation arise in a built-up layer in the location where distribution of a refractory metal is low by the heat | fever at the time of braking.

  The brake disk according to the present invention is a method of manufacturing a brake disk that brakes rotation of an axle by pressing a brake pad on a surface thereof, and is a disk mother attached to a rotating body that rotates integrally with the axle. Including a step of laminating a molten material in which particles of a refractory metal having a melting point higher than that of the disk base material are dispersed in a matrix material over a plurality of layers by powder overlaying plasma arc welding. Features.

  According to such a configuration, since the build-up layer containing the refractory metal is laminated on the surface of the disk base material, the heat generated when the brake pad is pressed against the brake disc is generated by the build-up layer. The presence reduces transmission to the disk base material. Therefore, it is possible to suppress the occurrence of cracks and deformation on the surface of the disk base material due to the influence of heat during braking. In addition, the overlay layer is laminated on the surface of the disk base material by powder overlay plasma arc welding, so that at the interface between the build-up layer and the surface of the disk base material, sufficient adhesion strength between them is obtained by melt bonding. Secured.

  In the brake disk according to the present invention, the weight ratio of the refractory metal occupying the whole of the molten material is approximately 80%.

  According to such a configuration, a built-up layer in which the weight ratio of the refractory metal occupying the whole is approximately 30% is laminated on the surface of the disk base material. Thereby, the refractory metal remains as metal particles in an appropriate amount after welding, and imparts high heat resistance to the disk base material.

  According to the brake disc of the present invention, it is possible to reliably suppress the occurrence of cracks and deformations in the disc base material even in a brake environment during high speed running.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front view showing an external appearance of a Shinkansen braking device including a brake disk according to an embodiment of the present invention. It is a schematic sectional drawing which shows the AA line cross section in FIG. It is a schematic sectional drawing which shows the surface vicinity of a brake disc. It is a graph which shows the Vickers hardness in each position of a disk base material. It is a schematic sectional drawing which shows the structure of a welding apparatus. It is a flowchart which shows the manufacturing process of the brake disc which concerns on this embodiment. It is a graph which shows the change of the heat conductivity accompanying a temperature change about a molten material and forged steel. It is a schematic front view which shows the external appearance of the braking device for bullet trains provided with the brake disc which concerns on the modification of this invention.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. First, the configuration of the brake disk according to the embodiment of the present invention will be described. FIG. 1 is a schematic front view showing an appearance of a Shinkansen braking apparatus 10 including a brake disk according to the present embodiment. 2 is a schematic cross-sectional view showing a cross section taken along line AA in FIG.

  As shown in FIG. 1, the Shinkansen braking device 10 includes a substantially circular wheel 11 (rotary body) in a side view, an axle 12 inserted through the wheel 11, and a brake disk 13 attached to an end surface of the wheel 11. And a brake pad 14 disposed in the vicinity of the brake disc 13.

  As shown in FIGS. 1 and 2, the wheel 11 includes a flat plate portion 111 having a certain thickness in the axial direction, a rim portion 112 in which a radially outer edge portion of the flat plate portion 111 protrudes in the axial direction, and a flat plate portion. 111 has a boss portion 113 having a radially central portion protruding in the axial direction, and a shaft insertion hole 114 formed through the boss portion 113.

  As shown in FIGS. 1 and 2, the axle 12 is fixed by being inserted into the shaft insertion hole 114 of the wheel 11. The axle 12 is driven to rotate by a motor or the like (not shown), so that the wheels 11 rotate integrally with the axle 12.

  The brake disk 13 plays a role of obtaining a braking force when the brake pad 14 is pressed. As shown in FIG. 1, the brake disk 13 is a flat plate member having a substantially annular shape in a side view, and has an outer diameter slightly smaller than an inner diameter of the rim portion 112 of the wheel 11. 11 is formed larger than the outer diameter of the boss portion 113. As shown in FIG. 2, the thickness of the brake disk 13 is formed to be approximately equal to the protruding height of the rim portion 112 with respect to the flat plate portion 111 of the wheel 11. Further, as shown in FIGS. 1 and 2, the brake disk 13 is formed with a plurality of bolt insertion holes 131 at predetermined intervals along the circumferential direction.

  Here, FIG. 3 is a schematic sectional view showing the vicinity of the surface of the brake disc 13. The brake disk 13 includes a disk base material 133 and a built-up layer 134 laminated on the surface of the disk base material 133 in three layers by powder overlaying plasma arc welding (hereinafter abbreviated as “PTA welding”). I have. It should be noted that the number of stacked layers 134 is not limited to the three layers of the present embodiment, and may be configured as two layers or four or more layers.

  The disk base material 133 is made of forged steel, which is a steel material for forging. Note that the material of the disk base material 133 is not limited to forged steel, and any material capable of performing PTA welding from the viewpoint of heat resistance or the like can be applied. For example, the disk base material 133 may be formed of pearlite cast iron having excellent thermal conductivity and wear resistance.

  The build-up layer 134 includes a first build-up layer 134A that is melt-bonded and stacked on the surface of the disk base material 133, and a second build-up layer that is melt-bonded and stacked on the surface of the first build-up layer 134A. 134B and a third built-up layer 134C laminated by being melt-bonded to the surface of the second built-up layer 134B. The surface of the third built-up layer 134 </ b> C located at the uppermost portion is configured as a friction surface 135 that should press the brake pad 14. In addition, as shown in FIG. 3, each build-up layer becomes a uniform integrated structure without a structure | tissue change, for the melt bond by welding.

  As shown in FIG. 3, the first build-up layer 134 </ b> A has a matrix material 136 and a refractory metal 137 dispersed in the matrix material 136. The matrix material 136 has a Vickers hardness of about 220 [Hv] to 270 [Hv]. The first built-up layer 134A configured in this manner is laminated on the surface of the disk base material 133 to a thickness of about 1 to 5 mm. In addition, since the 2nd overlay layer 134B and the 3rd overlay layer 134C are the same structures as the 1st overlay layer 134A, respectively, the description is abbreviate | omitted here.

  The matrix material 136 plays a role of bonding the refractory metal 137 uniformly. The matrix material 136 is made of a nickel-based alloy, and examples of the nickel-based alloy include Hastelloy (registered trademark) C alloy. Here, the Hastelloy C alloy is a material containing roughly 15% chromium (Cr), 16% molybdenum (Mo), 4% tungsten (W), and nickel (Ni) as the balance. is there. The matrix material 136 may be made of a material having high thermal conductivity such as copper alloy such as copper and aluminum bronze, silver and silver alloy, aluminum and aluminum alloy, in addition to the nickel base alloy. .

  The refractory metal 137 plays a role of imparting high heat resistance to the disk base material 133. The refractory metal 137 is a metal particle having a higher melting point than that of the disk base material 133, and any one of molybdenum (Mo), tungsten (W), niobium (Nb), and tantalum (Ta). Consists of more than seeds. And as for the refractory metal 137 comprised in this way, the weight ratio which occupies for the whole 1st overlay layer 134A is 50% or more and 80% or less.

  The metal particles constituting the refractory metal 137 have particles having an average particle diameter of 75 μm or more and 100 μm or less occupying 70% or more and 80% or less of the total number of particles, and particles having an average particle diameter of 10 μm or more and 45 μm or less remain. Particle size distribution.

  As shown in FIG. 2, the brake disk 13 configured as described above is disposed on the flat plate portion 111 with the side where the notch portion 132 is formed facing the wheel 11 side, and the bolt insertion hole 131 is provided. It is fixed to the wheel 11 by the fixing bolt 16 inserted.

  Further, the brake disk 13 is formed so that its outer diameter is slightly smaller than the inner diameter of the rim portion 112 and its inner diameter is larger than the outer diameter of the boss portion 113 as described above. Therefore, as shown in FIG. 2, a gap 17 having a predetermined width is formed between the brake disc 13 and the boss portion 113 in a state where the brake disc 13 is fixed to the flat plate portion 111 of the wheel 11.

  As shown in FIG. 1, the brake pad 14 is provided at a position corresponding to the brake disk 13 in the radial direction of the wheel 11. Although not shown in detail in the drawing, the brake pad 14 is provided so as to be movable in the axial direction of the wheel 11, and the axle 12 rotates integrally with the brake pad 14 by being pressed against the friction surface 135 of the brake pad 14. And the axle 12 is allowed to rotate by being separated from the brake pad 14.

  Next, the effect of the brake disc 13 according to the embodiment of the present invention will be described. In the brake disk 13 according to the present embodiment, the build-up layer 134 is laminated on the surface of the disk base material 133 by PTA welding. Therefore, at the interface between the disk base material 133 and the build-up layer 134, sufficient adhesion strength between the two is ensured by melt bonding. This prevents the build-up layer 134 from peeling off from the surface of the disk base material 133 in a braking environment during high-speed traveling.

  Moreover, the built-up layer 134 contains the refractory metal 137 at a weight ratio of 50% or more and 80% or less. Accordingly, the refractory metal 137 remains as metal particles in an appropriate amount after PTA welding, so that high heat resistance is imparted to the disk base material 133.

  Moreover, the built-up layer 134 has a Vickers hardness of the matrix material 136 of about 220 [Hv] or more and 270 [Hv] or less. The Vickers hardness of the build-up layer 134 is lower than 350 [Hv], which is a Vickers hardness that is generally used as a measure of whether cracks are generated and propagated. As a result, the build-up layer 134 is less likely to be cracked or deformed even in a braking environment during high-speed traveling.

  In addition, a hardened layer is generated in the disk base material 133 by heat treatment at the time of manufacture. However, when heat is applied by PTA welding during the lamination of the first overlay layer 134A, a hardened layer (not shown) is generated again. It hardens by being done. However, when the second build-up layer 134B is subsequently laminated, the heat generated by PTA welding is transferred to the disk base material 133 through the first build-up layer 134A, so that the amount of heat to be transferred is reduced. Therefore, the quenching layer generated again when the first build-up layer 134A is laminated is tempered by the heat applied during the lamination of the second build-up layer 134B. As a result, toughness is imparted to the hardened disk base material 133. Furthermore, when laminating the third overlay layer 134C, the heat generated by the PTA welding is transmitted to the disk base material 133 via the second overlay layer 134B and the first overlay layer 134A. Alleviated. Therefore, by tempering in the same manner as described above, further toughness is imparted to the disk base material 133. As described above, the disk base material 133 is less likely to be cracked or deformed even in a braking environment during high-speed traveling. The hardened layer generated on the disk base material 133 is further tempered by the heat generated during braking after the use of the brake disk 13 is started, so that the crack resistance of the disk base material 133 is further improved. .

  Here, FIG. 4 is a graph showing the Vickers hardness at each position of the disk base material 133, in which the horizontal axis indicates the distance from the surface of the disk base material 133 in the thickness direction, and the vertical axis indicates the Vickers hardness. Each is shown. In the figure, the black rhombus plot shows the case where the first build-up layer 134A is laminated without preheating the disk base material 133, and the white square plot shows the first after the disk base material 133 is preheated to 250 ° C. The black circle plot shows the case where the first built-up layer 134A is laminated, and the black circle plot shows the case where the first built-up layer 134A and the second built-up layer 134B are laminated in order after the disk base material 133 is preheated to 250 ° C. These plots respectively show the case where the disk base material 133 is preheated to 250 ° C. and then laminated in order from the first built-up layer 134A to the third built-up layer 134C. In FIG. 4, a “welding heat affected zone” that is a range from the surface of the disk base material 133 to a depth of about 2.8 mm means a range in which the heat of the PTA welding is exerted on the disk base material 133. In addition, the “base material original part” which is a deep range exceeding 2.8 mm means a range where the influence of heat at the time of PTA welding is not exerted on the disk base material 133.

  In FIG. 4, when the black rhombus plot and the white square plot are compared, the black rhombus plot is higher in Vickers hardness than the white square plot in the region of the heat affected zone. This is because in the black rhombus plot, the disk base material 133 is rapidly cooled after PTA welding by an amount not preheating the disk base material 133, so that the formation of a hardened layer is further promoted and the hardening proceeds.

  In FIG. 4, when the welding heat-affected zone and the base metal raw material portion of the white square plot are compared, the weld heat-affected zone has a higher Vickers hardness than the base metal raw material portion. This is because, in the welding heat affected zone, a hardened layer is generated on the disk base material 133 by heat when the first overlay layer 134A is PTA welded, and the disk base material 133 is thereby cured.

  When comparing the white square plot, the black circle plot, and the white triangle plot in FIG. 4, the Vickers hardness of the white square plot is higher than that of the black circle plot or the white triangle plot in the region of the heat affected zone. This is because, in the white square plot, only the first overlay layer 134A is laminated, so that the hardened layer is still generated in the disk base material 133, whereas in the black circle plot and the white triangle plot, the first overlay layer 134A. This is because toughness is imparted to the disk base material 133 by tempering the hardened layer generated at the time of lamination of the second built-up layer 134B and the third built-up layer 134C. The Vickers hardness of the black circle plot and the white triangle plot is lower than 350 [Hv], which is generally used as a measure of whether or not a crack is generated and propagates. As a result, the disk base material 133 is less likely to crack or deform.

  Next, a welding apparatus used for PTA welding will be described. FIG. 5 is a schematic cross-sectional view showing the configuration of the welding apparatus 20. As shown in FIG. 5, the welding apparatus 20 includes a gun 21, a tungsten electrode 22 inserted in the center of the gun 21, a main power source 23 connected to the tungsten electrode 22 and the disk base material 133, and a tungsten electrode 22. And a pilot power supply 24 connected to the gun 21.

  As shown in FIG. 5, the gun 21 has an electrode hole 211 formed in the center thereof, and the first flow path 212, the second flow path 213, and the first flow path around the electrode hole 211 from the inside toward the outside. Three flow paths 214 are respectively formed. The tungsten electrode 22 is inserted into the electrode hole 211 and the pilot gas PG is supplied. The first flow path 212 is supplied with the cooling water RW, the second flow path 213 is supplied with the melt 25 and the carrier gas CG, and the third flow path 214 is supplied with the shield gas SG. The melt 25 means a mixture of matrix material particles and refractory metal particles.

  According to the welding apparatus 20 configured as described above, the pilot power source 24 applies a voltage between the tungsten electrode 22 and the gun 21, so that an arc is blown from the tungsten electrode 22 and the pilot gas PG is turned into plasma. Then, when this plasma gas is cooled by the cooling water RW supplied to the first flow path 212, it is narrowed down by a so-called thermal pinch effect, and as a plasma arc PA having a high energy density, toward the disk base material 133. Spray. When this plasma arc PA reaches the disk base material 133, the main power source 23 applies a voltage between the tungsten electrode 22 and the disk base material 133, and details are not shown in the figure, but in the disk base material 133. Arc current flows, and a molten pool is formed on the surface of the disk base material 133. On the other hand, the melt 25 supplied to the second flow path 213 is pumped into the carrier gas CG and fed into the plasma arc PA, and is melted and put into the molten pool on the disk base material 133, so that A raised layer 134 is formed. The disk base material 133 and the built-up layer 134 are prevented from being oxidized by the shield gas SG supplied to the third flow path 214.

  Next, the procedure of the method for manufacturing the brake disk 13 according to the embodiment of the present invention will be described step by step. FIG. 6 is a flowchart showing a manufacturing process of the brake disc 13 according to the present embodiment. An operator who intends to manufacture the brake disk 13 first performs a base material manufacturing process (S1). That is, an operator produces the disk base material 133 by forging, rolling, or casting an ingot having a desired composition.

  Next, the worker performs a heat treatment step as necessary (S2). That is, the operator adjusts the structure in order to obtain the necessary characteristics of the manufactured disk base material 133.

  Next, the worker performs a machining process (S3). That is, although not shown in detail in the drawing, the operator expects the amount of distortion generated in the disk base material 133 in the PTA welding process to be described later, so that the overlay layer 134 after welding is in an appropriate state. A groove portion having a predetermined angle is formed in advance by partially cutting the surface of the material 133. In the present embodiment, the Vickers hardness of the disk base material 133 is lower than 400 [Hv], which can be generally machined, as shown as a base material base part in FIG. Therefore, machining of the disk base material 133 can be easily performed.

  Next, an operator performs a 1st PTA welding process (S4). That is, the operator welds the predetermined molten material 25 using the above-described welding apparatus 20, thereby laminating the first build-up layer 134 </ b> A on the surface of the disk base material 133. Here, the composition of the melt 25 is obtained by dispersing particles of the refractory metal 137 in a matrix material 136 made of, for example, a nickel base alloy, and the weight ratio of the refractory metal 137 occupying the entire melt 25 is approximately. 80%. However, the refractory metal 137 is diluted by melting the disk base material 133 during welding, and the first build-up layer 134A laminated on the surface of the disk base material 133 constitutes the refractory metal 137 occupying the whole. The weight ratio is 50% or more and 80% or less. In the first PTA welding process, a hardened layer is generated on the disk base material 133.

  Further, the molten material 25 has a characteristic of high thermal conductivity as compared with forged steel which is a raw material of the disk base material 133. FIG. 7: is a graph which shows the change of the heat conductivity accompanying a temperature change about the molten material 25 and forged steel, Comprising: The black rhombus plot means forged steel, and the white circle plot means the molten material 25, respectively. As shown in this figure, in a high temperature region exceeding 600 ° C., that is, in a braking environment during high speed running, the thermal conductivity of the molten material 25 is about 80% higher than the thermal conductivity of forged steel. Thereby, thermal stress is generated inside the first built-up layer 134A, and the occurrence of cracks and deformation in the first built-up layer 134A due to this is reduced compared to forged steel.

  Next, an operator performs a 2nd PTA welding process (S5). That is, the operator laminates the second built-up layer 134B by welding the melt 25 on the first built-up layer 134A laminated in the first PTA welding step in the same manner as described above. In the second PTA welding process, the quenched layer generated in the first PTA welding process is tempered.

  Next, an operator performs a 3rd PTA welding process (S6). That is, the operator laminates the third built-up layer 134C by welding the melt 25 in the same manner as described above on the second built-up layer 134B laminated in the second PTA welding process. In this third PTA welding process, the quenched layer generated in the first PTA welding process is further tempered.

  Next, the worker performs a machining process (S7). That is, the operator arranges the brake disc 13 formed by laminating the build-up layer 134 on the disc base material 133 into a desired outer shape by cutting or the like.

  Finally, the operator performs a finishing process (S8). That is, the operator finishes the surface of the friction surface 135 of the brake disk 13, in this embodiment, the third built-up layer 134 </ b> C, to a smooth surface. Thus, the brake disc 13 is completed and the manufacturing process of the brake disc 13 is completed.

  According to the method for manufacturing the brake disc 13 as described above, a hardened layer is generated on the disc base material 133 during the construction of the first PTA welding step (S6), and the second PTA welding step (S7) and the second step. The quenching layer is tempered during the construction of the three PTA welding process (S8). Therefore, it is not necessary to separately perform a heat treatment process such as quenching or tempering separately from the PTA welding process, and thus there is an advantage that the manufacturing process of the brake disk 13 can be simplified.

  In this embodiment, the PTA welding process is repeated three times. However, the number of times of performing the PTA welding process can be changed as appropriate in accordance with the number of stacked layers 134.

  Further, in the present embodiment, the case where the brake disk 13 is applied to the Shinkansen braking device 10 has been described as an example. However, the present invention is not limited to this, and the present invention can also be applied to a braking device for a railway vehicle other than the Shinkansen. Moreover, it is also possible to apply to the braking device of vehicles other than a rail vehicle. The rotating body according to the present invention is not limited to the wheel 11 but may be a hub (not shown) fixed to the axle 12.

  The various shapes, combinations, operation procedures, and the like of the constituent members shown in the above-described embodiments are merely examples, and various changes can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, the brake disc 13 according to the present embodiment shown in FIG. 1 is a so-called center fastening method in which a central portion in the radial direction is fixed to the wheel 11 via a fixing bolt 16. However, instead of this, as shown in FIG. 8, it is also possible to configure the brake disk 13 as a so-called inner periphery fastening system in which the radially inner periphery is fixed to the wheel 11 via the fixing bolt 16. It is.

DESCRIPTION OF SYMBOLS 10 Shinkansen brake device 11 Wheel 12 Axle 13 Brake disk 14 Brake pad 16 Fixing bolt 17 Gap 20 Welding device 21 Gun 22 Tungsten electrode 23 Main power supply 24 Pilot power supply 25 Melting material 111 Flat plate part 112 Rim part 113 Boss part 114 Shaft insertion hole 131 Bolt insertion hole 132 Notch 133 Disc base material 134 Overlay layer 135 Friction surface 136 Matrix material 137 Refractory metal 211 Electrode hole 212 First flow path 213 Second flow path 214 Third flow path 134A First buildup layer 134B First Two overlay layers 134C Third overlay layer CG Carrier gas PA Plasma arc PG Pilot gas RW Cooling water SG Shield gas

Claims (8)

A brake disc that brakes the rotation of the axle by pressing a brake pad on the surface,
A disk base material attached to a rotating body that rotates integrally with the axle;
Stacked over a plurality of layers on the surface of the disk base material, and a built-up layer in which particles of a refractory metal having a melting point higher than that of the disk base material are dispersed in a matrix material,
Equipped with a,
The refractory metal is characterized in that particles having an average particle size of 75 μm or more and 100 μm or less occupy 70% or more and 80% or less of the total number of particles, and particles having an average particle size of 10 μm or more and 45 μm or less occupy the rest. brake disc.   The brake disk according to claim 1, wherein the build-up layer is laminated on the surface of the disk base material by powder build-up plasma arc welding.   The brake disk according to claim 1 or 2, wherein the build-up layer is laminated on the surface of the disk base material in two or more layers.   4. The brake disk according to claim 1, wherein the refractory metal contains at least one of molybdenum, tungsten, niobium, and tantalum. 5.   The brake disk according to any one of claims 1 to 4, wherein the build-up layer contains the refractory metal in a weight ratio of 50% to 80%. The brake disk according to any one of claims 1 to 5 , wherein the matrix material is made of a nickel-based alloy. A brake disk manufacturing method for braking rotation of an axle by pressing a brake pad on a surface,
On the surface of a disk base material attached to a rotating body that rotates integrally with the axle, a molten material in which particles of a refractory metal having a melting point higher than that of the disk base material are dispersed in a matrix material, Including the step of laminating over multiple layers by arc welding ,
The refractory metal is characterized in that particles having an average particle size of 75 μm or more and 100 μm or less occupy 70% or more and 80% or less of the total number of particles, and particles having an average particle size of 10 μm or more and 45 μm or less occupy the rest. Brake disc manufacturing method. The method for manufacturing a brake disk according to claim 7 , wherein the molten material has a weight ratio of the refractory metal occupying the whole of about 80%.

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