JP6311554B2 - Railway wheel with brake disc - Google Patents

Description

  The present invention relates to a railway wheel with a brake disk (hereinafter also referred to as “railway wheel with BD”) in which a brake disk is fastened to a wheel for a railway vehicle.

  As a braking device for a railway vehicle, a disc brake having excellent braking performance is frequently used as the speed and size of the vehicle increase. In a disc brake, a brake lining is pressed against a sliding surface of a brake disc attached to a wheel. As a result, braking force is generated on the rotating wheels, and the speed of the vehicle is controlled.

  1A and 1B are views showing the overall structure of a railway wheel with a brake disc that constitutes a disc brake of a railway vehicle. FIG. 1A is a plan view of a quarter circle portion, and FIG. Sectional views along the axial direction are shown. 2A to 2C are views locally showing the structure of a conventional BD-equipped railway wheel. FIG. 2A is a perspective view of the rear surface of the brake disk as viewed from the inner peripheral surface side, and FIG. A plan view seen from the back side is shown in FIG. 2C and a sectional view along the axial direction is shown.

  As shown in FIGS. 1A, 1B, and 2A to 2C, the brake disc 1 includes a donut-shaped disk portion 2 having a sliding surface on the surface 2a side. A plurality of fin portions 3 are radially provided on the rear surface 2 b of the disk portion 2. Some of the plurality of fin portions 3 are formed with bolt holes 4 penetrating to the disc portion 2 at substantially the center position in the radial direction.

  The wheel 10 includes a boss portion 11 into which an axle is press-fitted, a rim portion 12 including a tread surface that comes into contact with a rail, and a plate portion 13 that couples them. The brake disc 1 is arranged so as to sandwich the plate portion 13 of the wheel 10 with the two surfaces as a set and the individual surfaces 2a facing outward. Bolts 5 are inserted into the respective bolt holes 4, and nuts 6 are screwed into the respective bolts 5 and tightened. As a result, the brake disc 1 is fastened to the wheel 10 in a state in which the front end surface (axial end surface) of the fin portion 3 is in pressure contact with the side surface 13a of the plate portion 13 of the wheel 10 over the entire radial direction. The conventional railway wheel with BD of such a structure is disclosed by patent document 1, for example.

  During travel of the railway vehicle, the brake disc 1 rotates at a high speed integrally with the wheel 10. Accordingly, the air around the brake disc 1 flows into the space formed between the brake disc 1 and the wheel 10, specifically, the disc portion 2 and the fin portion 3 of the brake disc 1, and the wheel. 10 flows in from the inner peripheral side and flows out from the outer peripheral side into a space surrounded by 10 plate portions 13 (see solid arrows in FIGS. 2A to 2C). In short, an air gas flow is generated in the space between the brake disc 1 and the wheel 10 during travel of the railway vehicle. This gas flow becomes significant when traveling at a high speed exceeding 300 km / h like a high-speed railway vehicle such as the Shinkansen (R) and induces a noise called aerodynamic sound. For this reason, reduction of aerodynamic sound is required for environmental considerations.

  There are the following as conventional techniques corresponding to this requirement.

  For example, Patent Document 2 discloses a railway wheel with a BD in which a rib is added along the circumferential direction between adjacent fin portions of a brake disk, and the gas flow is suppressed by the rib. According to the railway wheel with BD disclosed in this document, aerodynamic sound can be reduced to a desired level.

  However, in the technique disclosed in Patent Document 2, the cooling performance to the brake disc is reduced during braking along with the suppression of the gas flow by the ribs. For this reason, coupled with the increase in rigidity of the brake disc itself due to the addition of ribs, the deformation accompanying the thermal expansion of the brake disc and the resulting stress load on the fastening bolt increase, and the durability of the brake disc and bolt decreases. There is a risk.

  A conventional technique for solving this problem is disclosed in Patent Document 3.

  3A and 3B are views locally showing the structure of a conventional BD-equipped railway wheel disclosed in Patent Document 3, and FIG. 3A is a perspective view of the rear surface of the brake disc as seen from the inner peripheral surface side. FIG. 3B shows a cross-sectional view along the axial direction. As shown in these drawings, in the railway wheel with BD disclosed in Patent Document 3, ribs 7 are added along the circumferential direction between the adjacent fin portions 3 for the brake disc 1, and this A slit 7 a is formed along the radial direction at the center of the rib 7 in the circumferential direction.

  According to this BD-equipped railway wheel, the gas flow is secured by the slit 7a. For this reason, the cooling performance to the brake disc 1 is maintained during braking, and the increase in rigidity due to the addition of the rib is mitigated, so that deformation due to thermal expansion of the brake disc 1 and stress load on the fastening bolts are caused. This reduces the deterioration of the durability of the brake disc 1 and the bolt.

  Non-Patent Document 1 discloses a BD-equipped railway wheel in which an air dam that suppresses the flow of air is provided at the radially inner end of the fin portion instead of the rib of Patent Document 3. The air dam is a plate-like portion along the circumferential direction of the brake disc. A gap is formed between the air dams in the adjacent fins. This gap ensures gas flow, maintains the cooling performance of the brake disc during braking, and increases the rigidity by adding an air dam. Is alleviated. That is, this gap has the same function as the slit of Patent Document 3.

Japanese Patent Laid-Open No. 2006-9862 JP 2007-205428 A International Publication WO2010 / 071169 Pamphlet

Masahiko Horiuchi, “Development of basic braking system for Shinkansen in Knorr-Bremse”, Railway Vehicles and Technology, No. 202, p13-17

  As described above, conventional BD-equipped railway wheels that reduce aerodynamic noise focus on suppressing the gas flow in the space surrounded by the disc and fins of the brake disc and the plate of the wheel. ing. In order to suppress such gas flow, these railway wheels have ribs added to the disc brake disc, or slits formed in the ribs, or air dams added to the fins of the disc brake. A gap is formed between the air dams. For this reason, since the shape of the brake disc becomes complicated, the productivity of the brake disc must be reduced.

  Specifically, not only the fin but also additional work (machining, etc.) to adjust the height of the rib or air dam is required. Furthermore, when providing a rib, additional work to form a slit in the rib is required. As a result, the brake disk manufacturing process becomes complicated. In particular, when the brake disc is manufactured by forging, it cannot be denied that the load on the mold increases and the mold life is shortened.

The present invention has been made in view of the above problems, and an object thereof is to provide a railway wheel with a brake disk having the following characteristics:
-The brake disc must have a simple shape and excellent productivity;
・ Effectively reduce aerodynamic noise during high-speed driving while ensuring sufficient heat dissipation.

A railway wheel with a brake disk according to an embodiment of the present invention,
A wheel for a railway vehicle composed of a boss part, a rim part, and a plate part connecting them;
A donut-shaped disk part having a sliding surface on the surface side, and a brake disk composed of a plurality of fin parts projecting radially on the back surface of the disk part,
Two brake discs sandwiching the plate portion of the wheel with each sliding surface facing outward, and a train wheel with a brake disc fastened,
The inner peripheral surface of the rim portion is composed of a tapered surface connected to the side surface of the rim portion, and a fillet surface connected to the tapered surface and the side surface of the plate portion,
Regarding the area of the cross section that crosses the space formed between the brake disc and the wheel along the circumferential direction, the minimum cross section where the cross sectional area is the smallest is the outer peripheral surface of the disk portion and the rim. Of the region formed by the inner peripheral surface of the part, exists at the boundary between the tapered surface and the fillet surface of the rim part,
The outer peripheral surface of the disc portion is divided into an outer region surface and an inner region surface with the minimum cross-sectional portion as a boundary,
In a cross section along the axial direction of the wheel, an angle α formed by the inner region surface and a portion of the fillet surface near the minimum cross section satisfies 0 ° ≦ α ≦ 6 °, and the outer region surface and the An angle β formed with the tapered surface satisfies 0 ° ≦ β ≦ 35 °, and an angle γ formed between the sliding surface and the tapered surface satisfies 30 ° ≦ γ ≦ 45 °.

The railway wheel with brake disc of the present invention has the following remarkable effects:
-The brake disc must have a simple shape and excellent productivity;
・ Aerodynamic noise during high-speed traveling can be effectively reduced while ensuring sufficient heat dissipation.

FIG. 1A is a diagram showing an overall structure of a railway wheel with a brake disk, and is a plan view of a ¼ circle portion. FIG. 1B is a diagram showing the overall structure of a railway wheel with a brake disc, and is a cross-sectional view along the axial direction of a semicircular portion. FIG. 2A is a diagram locally showing the structure of a conventional railway wheel with a brake disc, and is a perspective view of the rear surface of the brake disc as seen from the inner peripheral surface side. FIG. 2B is a diagram locally showing the structure of a conventional railway wheel with a brake disc, and is a plan view of the brake disc as seen from the back side. FIG. 2C is a diagram locally showing a structure of a conventional railway wheel with a brake disc, and is a cross-sectional view along the axial direction. FIG. 3A is a diagram locally showing the structure of a conventional railway wheel with a brake disk disclosed in Patent Document 3, and is a perspective view of the rear surface of the brake disk as viewed from the inner peripheral surface side. FIG. 3B is a diagram locally showing a structure of a conventional railway wheel with a brake disk disclosed in Patent Document 3, and is a cross-sectional view along the axial direction. FIG. 4 is a diagram showing a correlation between the sum of the opening areas, the aerodynamic sound level, and the air flow rate in the railway wheel with a brake disk. FIG. 5 is a diagram showing the distribution of gas pressure fluctuations on the solid surface (brake disc and wheel surfaces) obtained by unsteady gas flow analysis. FIG. 6A is a cross-sectional view along the axial direction showing locally the structure of a railway wheel with a brake disk according to an embodiment of the present invention. FIG. 6B is an enlarged cross-sectional view of a portion indicated by a rectangular frame in FIG. 6A. FIG. 7A is a cross-sectional view along the axial direction showing locally the structure of the railway wheel with a brake disk of Example 1 of the present invention. FIG. 7B is a cross-sectional view along the axial direction showing locally the structure of the railway wheel with a brake disk of Example 2 of the present invention. FIG. 7C is a cross-sectional view along the axial direction showing locally the structure of the railway wheel with a brake disk of Example 3 of the present invention. FIG. 7D is a cross-sectional view along the axial direction showing locally the structure of the railway wheel with a brake disk of Comparative Example 1. FIG. 7E is a cross-sectional view along the axial direction showing locally the structure of the railway wheel with a brake disk of Comparative Example 2. FIG. 7F is a cross-sectional view along the axial direction showing locally the structure of the railway wheel with a brake disk of Comparative Example 3. FIG. 8 is a diagram showing the relationship between the heat radiation index and the aerodynamic sound level for the railway wheels with brake disks of Examples 1 to 3 and Comparative Examples 1 to 3.

  As described in Patent Document 3, the space formed between the brake disc and the wheel, in particular, the disk portion and the fin portion of the brake disc, and the air flowing through the space surrounded by the plate portion of the wheel There is a strong correlation between airflow and aerodynamic sound level.

  FIG. 4 is a diagram showing a correlation between the sum of the opening areas, the aerodynamic sound level, and the air flow rate in the railway wheel with a brake disk. The sum of the opening areas here refers to the entire area in the circumferential direction of the opening area when viewed from the inner peripheral side of the brake disc in the space surrounded by the disc disc and fin portions of the brake disc and the plate portion of the wheel. It is the sum total. In other words, the sum of the opening areas is the minimum cross-sectional area of the cross section that crosses the space formed between the brake disc and the wheel along the circumferential direction (hereinafter referred to as “space cross section”). Is the area of the smallest cross-sectional portion. For example, as in the railway wheel with BD shown in FIGS. 3A and 3B, when a rib is added between the fin portions of the brake disc and a slit is formed in the rib, the minimum cross-sectional portion is the position of the rib. Therefore, the area of the spatial cross section at the position of the rib is the sum of the opening areas shown in FIG. The air flow rate was obtained by thermal fluid analysis (per brake disc), and the aerodynamic sound level was obtained by experiments.

  As shown in FIG. 4, it can be seen that the aerodynamic sound level increases with an increase in the area of the minimum cross-sectional portion (the total sum of the opening areas), and the air flow rate has the same tendency.

  However, in practice, aerodynamic sound is caused by an unsteady change in gas pressure (propagation phenomenon of dense waves). For this reason, when the generation of aerodynamic sound is predicted by numerical analysis, it is preferable to directly evaluate the essentially unsteady change in gas flow and the accompanying change in sound pressure.

  Therefore, the conventional railway wheel with BD shown in FIG. 3A and FIG. 3B, that is, the railway wheel with BD in which a rib with a slit is added between the fin portions, the aerodynamic sound level based on the unsteady gas flow analysis is targeted. Direct prediction was performed. In this analysis, the traveling speed was kept constant at 360 km / h.

The typical conditions of the model of the railway wheel with BD used for the unsteady gas flow analysis are as follows.
<Brake disc>
-Forged steel disk for Shinkansen (R)-Inner diameter of disc part: 417 mm, outer diameter of disc part: 715 mm
-Length from the sliding surface of the disc part to the tip surface of the fin part (contact surface with the wheel plate part): 45 mm
-Twelve bolt holes centered on the same circle with a diameter of 560 mm are formed at equal intervals, and bolts are inserted into each bolt hole to fasten the brake disc and wheel.
<Wheel>
-Rolling wheels for Shinkansen (R)-Inner diameter: 196 mm, outer diameter: 860 mm

  First, the aerodynamic sound level was measured by the method described in Patent Document 2, and the validity of the calculation method for unsteady gas flow analysis was verified. Specifically, after measuring sound pressure data with a precision sound level meter through experiments, frequency analysis is performed, A characteristic correction is applied, and 1/3 octave band processing is performed to calculate frequency characteristic data and overall values. did. And about the overall value, the experimental value (114.5 [dB (A)]) and the calculated value (114.8 [dB (A)]) were compared, and both consistency was confirmed.

  FIG. 5 is a diagram showing the distribution of gas pressure fluctuations on the solid surface (brake disc and wheel surfaces) obtained by unsteady gas flow analysis. FIG. 4A shows both the brake disc and the surface of the wheel, and FIG. 2B shows the brake disc through the brake disc.

  The gas pressure fluctuation on the solid surface shown in FIG. 5 indicates the mean square amount of the time differential value of the pressure, which corresponds to the sound source distribution on the solid surface (the surfaces of the brake disc and the wheel). As is clear from the distribution of the dark portion of the light and shade display in FIG. 5, the main sound source during traveling is the gas outflow region and the vicinity thereof, that is, the brake disc in the space formed between the brake disc and the wheel. It appears in the outer peripheral region of the disc portion and in the vicinity thereof.

  Therefore, in the present invention, in order to reduce aerodynamic noise, the disc disk portion and the fin portion of the brake disc, which have been focused on in the prior art, and the wheel in the space formed between the brake disc and the wheel. Instead of the space surrounded by the plate portion, it is formed by the outer peripheral region of the disc portion of the brake disc that becomes the gas outflow region, that is, the outer peripheral surface of the disc portion of the brake disc and the inner peripheral surface of the rim portion of the wheel. We focused on the area.

  Then, the numerical calculation based on the unsteady gas flow analysis described above was used to investigate the influence of the shape of the outer peripheral region of the disc part of the brake disc on the aerodynamic sound level and the cooling performance. As a result, if the shape of the outer peripheral surface of the brake disc is properly defined, the present invention has been completed with the knowledge that the aerodynamic sound level can be further suppressed while maintaining the cooling performance equivalent to or higher than that of the prior art. I let you.

  In general, the more rapid the change in direction of the gas flow, the greater the dissipation of kinetic energy due to viscous stress, and the more easily the gas flow is converted to energy that generates sound. In this respect, the present invention pays attention to the gas flow in the gas outflow region, and adjusts the gas flow from between the brake disc and the wheel so as to follow the surface (side surface) of the rim portion of the wheel. And a gas flow outward in the radial direction along the sliding surface generated at the same time so as to join at a small angle. Thereby, the direction change of the gas flow in the vicinity of the confluence where it is likely to be a sound source is minimized, and aerodynamic noise is reduced.

  Below, the embodiment of the railway wheel with a brake disk of the present invention is described in detail.

  6A and 6B are cross-sectional views along the axial direction (hereinafter, referred to as “axial cross-section”) that locally show the structure of the railway wheel with a brake disk according to one embodiment of the present invention. 6B is an enlarged cross-sectional view illustrating a range indicated by a rectangular frame F in FIG. 6A. Below, the same code | symbol is attached | subjected to the part which is common in the conventional railway wheel with BD shown in the said FIG. 1A, FIG. 1B, and FIG. 2A-FIG. 2C, and the overlapping description is abbreviate | omitted suitably.

  As shown in FIGS. 6A and 6B, the brake disc 1 in this embodiment includes a disk portion 2 and a fin portion 3. The brake disc 1 does not have the rib 7 as shown in FIGS. 3A and 3B and the air dam disclosed in Non-Patent Document 1. In short, the plurality of fin portions 3 are only protruded radially on the back surface 2b of the disc portion 2. The disc part 2 has a shape such as a truncated cone or a column.

  As a material of the brake disc 1, cast iron, cast steel, forged steel, aluminum, carbon, or the like can be used.

  As shown in FIG. 6B, a region excluding the outer peripheral region surface 2a1 in the surface 2a of the brake disc 1 is a sliding surface 2a2. The sliding surface 2a2 is one step higher than the outer peripheral region surface 2a1, and a step is formed between the outer peripheral region surface 2a1 and the sliding surface 2a2. The sliding surface 2a2 wears with repeated braking, and when the wear of the sliding surface 2a2 proceeds to the height of the outer peripheral area surface 2a1 of the disc portion 2 (shown by a broken line in FIG. 6B), the brake disc 1 Are exchanged.

  The wheel 10 includes a boss portion 11, a rim portion 12, and a plate portion 13. An inner peripheral surface 12b (range from point b1 to point b4 in FIG. 6B) of the rim portion 12 is a tapered surface 12ba (range from point b1 to point b2 in FIG. 6B) connected to the side surface 12a of the rim portion 12, and tapered. A fillet surface 12bb (range from point b2 to point b4 in FIG. 6B) connected to the surface 12ba and the side surface 13a of the plate portion 13 is included.

  As shown in FIG. 6B, the tapered surface 12ba is substantially linear in the axial section. The fillet surface 12bb has a substantially straight line portion 12bb1 (range from point b2 to point b3 in FIG. 6B) and a curved curve portion 12bb2 (in FIG. 6B) convex toward the wheel 10 side in the axial cross section. Point b3 to point b4). The straight portion 12bb1 is connected to the tapered surface 12ba, and the curved portion 12bb2 is connected to the side surface 13a of the plate portion 13. The curved portion 12bb2 may be an R surface with a constant radius of curvature, or may be a free curved surface with a changing radius of curvature.

  Here, in the railway wheel with BD of this embodiment, the area of the space cross section is the smallest for the space cross section that crosses the space formed between the brake disc 1 and the wheel 10 along the circumferential direction. The minimum cross-sectional portion is present in a region formed by the outer peripheral surface 2 c of the disc portion 2 of the brake disc 1 and the inner peripheral surface 12 b of the rim portion 12 of the wheel 10. Specifically, the minimum cross-sectional portion exists on the boundary (point b2) between the tapered surface 12ba and the fillet surface 12bb on the inner peripheral surface 12b of the rim portion 12.

  Further, the outer peripheral surface 2c (the range from the point a1 to the point a3 in FIG. 6B) of the disc part 2 of the brake disc 1 is bounded by the minimum cross-sectional part (the position of the point a2) along the thickness direction from here. The outer region surface 2c1 on the outer side (surface 2a side) (range from point a1 to point a2 in FIG. 6B) and the inner region surface 2c2 on the inner side (range from point a2 to point a3 in FIG. 6B). In the cross section in the axial direction, the outer region surface 2c1 and the inner region surface 2c2 are both substantially linear.

  In the axial cross section, the angle formed by the surfaces is defined as follows. An angle α formed by the inner region surface 2c2 (straight line passing through the points a2 and a3) and the straight line portion 12bb1 (straight line passing through the points b2 and b3) satisfies 0 ° ≦ α ≦ 6 °. An angle β formed by the outer region surface 2c1 (a straight line passing through the points a1 and a2) and the tapered surface 12ba (a straight line passing through the points b1 and b2) satisfies 0 ° ≦ β ≦ 35 °.

  Since 0 ° ≦ β ≦ 35 °, β may not be 0, that is, the shape of the outer region surface 2c1 may not be completely along the tapered surface 12ba. Even in this case, when the angle α formed by the inner region surface 2c2 and the straight portion 12bb1 satisfies 0 ° ≦ α ≦ 6 °, the flow of gas flows due to rectification at the contracted portion formed between the two surfaces. While the fluctuation is suppressed, the change in the direction of the gas flow in the vicinity of the confluence where the sound source is likely to be a sound source is mitigated, and aerodynamic sound is effectively reduced.

  In the railway wheel with BD having such a configuration, the brake disk 1 does not have the rib 7 and the air dam, and only includes the fin portion 3 on the back surface of the disc portion 2 and has a simple shape. For this reason, the manufacturing process of the brake disc 1 is not complicated, and the productivity of the brake disc 1 is excellent. Even when the brake disk 1 is manufactured by forging, the load on the mold does not increase and the mold life is not shortened. However, the outer peripheral surface 2c of the disc portion 2 of the brake disc 1 needs to be machined into a shape in which the angles α and β satisfy the above requirements, but this machining is performed using conventional ribs, air dams, and slits. Unlike the additional machining, it can be easily performed in a series of machining of the brake disc 1.

  In addition, according to the railway wheel with BD, during high speed traveling, the air flowing between the brake disc 1 and the wheel 10 finally becomes the tapered surface 12ba of the rim portion 12 and the outer region surface 2c1 of the disc portion 2. It flows out along the direction prescribed by. For this reason, the air that has flowed out between the brake disc 1 and the wheel 10 is joined at a small angle with the radially outward gas flow along the sliding surface 2a2 generated as the brake disc 1 rotates. Become.

  The length γ of the tapered surface 12ba in the axial section is obtained while the effect of such merging is obtained by making the angle γ formed by the sliding surface 2a2 and the tapered surface 12ba satisfy 30 ° ≦ γ ≦ 45 °. L can be prevented from becoming excessively long. The length L satisfies, for example, 10 mm ≦ L ≦ 20 mm.

  In the axial cross section, an angle ζ formed by the sliding surface 2a2 and the straight portion 12bb1 (a straight line passing through the points 2b and b3) is, for example, 70 ° ≦ ζ ≦ 85 °.

  In order to confirm the effect of the railway wheel with BD of the present invention, unsteady gas flow analysis and thermal fluid analysis were performed, and the aerodynamic sound level, the cooling performance, and the air flow rate were evaluated. 7A to 7F are axial cross-sectional views of a railway wheel with a BD that is an object of analysis. 7A to 7F, the same reference numerals are given to the portions common to the railway wheel with BD shown in FIGS. 6A and 6B. 7A to 7C are sectional views of railway wheels with BD that satisfy the requirements of the present invention (invention examples 1 to 3, respectively). FIGS. 7D to 7F are railways with BD that do not satisfy the requirements of the present invention. It is sectional drawing of a wheel (respectively Comparative Examples 1-3). 7A to 7E, a portion indicated by two black circles connected by a line segment is a minimum cross-sectional portion.

  Table 1 shows the angle α formed between the inner region surface 2c2 and the straight portion 12bb1, the angle β formed between the outer region surface 2c1 and the tapered surface 12ba, and the area of the minimum cross-sectional portion for each BD railway wheel.

In the axial cross section, the angle γ formed by the sliding surface 2a2 and the tapered surface 12ba, the length L of the tapered surface 12ba, and the angle ζ formed by the sliding surface 2a2 and the straight portion 12bb1 are the first to third examples of the present invention and It was made common in Comparative Examples 1-3, and the following value was taken.
・ Γ: 38.5 °
・ L: 11mm
・ Ζ: 77 °

  As Comparative Example 3, a railway wheel with BD in which ribs 7 with slits 7a (see FIGS. 3A and 3B) were added between adjacent fin portions 3 was adopted.

  For each BD railway wheel, the air and heat flow during vehicle travel were numerically analyzed. The typical conditions of the model of the railway wheel with BD used for the analysis are the same as those in the above-described unsteady gas flow analysis. The unsteady gas flow analysis method is also the same. In both the unsteady gas flow analysis and the thermal fluid analysis, the traveling speed was kept constant at 360 km / h.

As an evaluation index of cooling performance, a heat dissipation index defined by an integrated value of the average heat transfer coefficient and surface area of the surface per brake disc was introduced. The larger the heat dissipation index, the better the cooling performance.
FIG. 8 shows the aerodynamic sound level and the heat radiation index of each BD-equipped railway wheel.

  The air flow rate was evaluated by the time average of the air flow rate at the minimum cross section of the space cross section between the brake disc and the wheel, and its fluctuation range. Table 1 also shows the average airflow and the airflow fluctuation range of each BD railway wheel.

  As shown in FIG. 8, Examples 1 to 3 of the present invention can reduce the aerodynamic sound level while improving the cooling performance as compared with Comparative Example 3 which is a prior art provided with ribs. On the other hand, in Comparative Examples 1 and 2, which are similar in shape to the present invention but outside the scope of the invention, they are formed between the inner region surface 2c2 of the disk portion outer peripheral surface and the fillet surface straight portion 12bb1 of the rim inner peripheral surface. The effect of rectification at the contracted flow portion is insufficient, and although the cooling ability can be improved, the aerodynamic sound level is also increased.

  Further, as shown in Table 1, Examples 1 to 3 of the present invention have a larger area of the minimum cross section than Comparative Example 3, so that the average air flow rate is increased and the cooling performance is high. Moreover, Examples 1-3 of the present invention have a smaller fluctuation range of the air flow than Comparative Example 3, and improve the quietness. From this, it can be said that the quietness of the railway wheel with BD and the cooling performance of the brake disc at the time of braking can be appropriately controlled by appropriately changing the area of the minimum cross section which is a design factor. Even if the material of the brake disc 1 is any of cast iron, cast steel, forged steel, aluminum, carbon and the like, the same effect can be obtained.

  The railway wheel with a brake disc of the present invention can be effectively used for any railway vehicle having a disc brake, and is particularly useful for a high-speed railway vehicle.

1: Brake disc,
2: disk part, 2a: front surface, 2a2: sliding surface, 2b: back surface,
2c: outer peripheral surface, outer region surface: 2c1, inner region surface: 2c2,
3: Fin part, 4: Bolt hole, 5: Bolt, 6: Nut,
7: Rib, 7a: Slit, 10: Wheel, 11: Boss part,
12: Rim part, 12a: Side surface, 12b: Inner peripheral surface,
12ba: taper surface, 12bb: fillet surface,
12bb1: straight portion, 13: plate portion, 13a: side surface

Claims (3)

A wheel for a railway vehicle composed of a boss part, a rim part, and a plate part connecting them;
A donut-shaped disk part having a sliding surface on the surface side, and a brake disk composed of a plurality of fin parts projecting radially on the back surface of the disk part,
Two brake discs sandwiching the plate portion of the wheel with each sliding surface facing outward, and a train wheel with a brake disc fastened,
The inner peripheral surface of the rim portion is composed of a tapered surface connected to the side surface of the rim portion, and a fillet surface connected to the tapered surface and the side surface of the plate portion,
Regarding the area of the cross section that crosses the space formed between the brake disc and the wheel along the circumferential direction, the minimum cross section where the cross sectional area is the smallest is the outer peripheral surface of the disk portion and the rim. Of the region formed by the inner peripheral surface of the part, exists at the boundary between the tapered surface and the fillet surface of the rim part,
The outer peripheral surface of the disc portion is divided into an outer region surface and an inner region surface with the minimum cross-sectional portion as a boundary,
In a cross section along the axial direction of the wheel, an angle α formed by the inner region surface and a portion of the fillet surface near the minimum cross section satisfies 0 ° ≦ α ≦ 6 °, and the outer region surface and the A railway wheel with a brake disk, wherein an angle β formed with a tapered surface satisfies 0 ° ≦ β ≦ 35 °, and an angle γ formed between the sliding surface and the tapered surface satisfies 30 ° ≦ γ ≦ 45 °. A railway wheel with a brake disk according to claim 1,
A railway wheel with a brake disk, wherein an angle ζ between the sliding surface and a portion in the vicinity of the minimum cross section of the fillet surface satisfies 70 ° ≦ ζ ≦ 85 ° in a cross section along the axial direction of the wheel. A railway wheel with a brake disk according to claim 1 or 2,
A railway wheel with a brake disk, wherein a length L of the tapered surface satisfies 10 mm ≦ L ≦ 20 mm in a cross section along the axial direction of the wheel.