Wheel

Abstract

To provide an undulating wheel for a railway vehicle that is able to improve quietness without using an additional component.SOLUTION: A wheel (100, 100A, 100B) includes a boss portion (10), a rim portion (20), and a plate portion (30). The rim portion (20) includes a flange (22). The plate portion (30) is formed so as to undulate in a circumferential direction. The plate portion (30) includes a curved portion (31, 32). The curved portion (31) is curved so as to protrude toward the flange (22), and a top part of the curved portion is disposed on a boss portion (10) side with respect to a center (Cw) of the plate portion (30). The curved portion (32) is curved so as to protrude toward a side opposite to the flange (22), and a top part of the curved portion is disposed on a rim portion (20) side with respect to the center (Cw) of the plate portion (30). The wheel (100, 100A, 100B) has a plate thickness change cross-section. In the plate thickness change cross-section, a plate thickness of the plate portion (30) is not constant in a range (Rw) from the curved portion (31) to the curved portion (32), and the plate thickness is maximized at the curved portion (32).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to wheels for rail vehicles. [Background technology]

[0002] A railway vehicle wheel comprises a boss portion, a rim portion, and a plate portion. An axle is inserted into the boss portion. The rim portion is disposed on the outer periphery of the boss portion. The rim portion includes a tread surface and a flange. The tread surface is the surface that contacts the top surface of the rail. The flange protrudes outward from the tread surface in the radial direction of the wheel. The plate portion connects the rim portion and the boss portion.

[0003] Corrugated wheels are known as one type of wheel for railway vehicles. Corrugated wheels are wheels whose plate portions are corrugated in the circumferential direction of the wheel. The corrugated shape of the plate portion of a corrugated wheel makes it easier to ensure the strength of the plate portion, allowing the plate thickness of the plate portion to be reduced. As a result, corrugated wheels have the advantage of being lighter than non-corrugated wheels. On the other hand, corrugated wheels generally obtain braking force through tread brakes. Due to the shape of the plate portion of a corrugated wheel, thermal stress caused by the tread brakes is likely to be large.

[0004] Patent Documents 1 and 2 propose corrugated wheels designed to reduce thermal stress generated in the plate portion due to braking. In the corrugated wheel of Patent Document 1, the rim portion is located outside the track relative to the boss portion. In this corrugated wheel, the axial distance from the rim-side fillet to the boss-side fillet in a radial cross section at the lowest point of the waves on the plate portion as viewed from the flange side is defined as the eccentricity, and the eccentricity is set within a predetermined range. Furthermore, the axial distance between the boss-side fillet in a radial cross section at the highest point of the waves on the plate portion as viewed from the flange side and the boss-side fillet in a radial cross section at the lowest point of the waves on the plate portion as viewed from the flange side is defined as the wave depth of the boss-side plate portion, and the wave depth is set within a predetermined range. Patent Document 1 states that this configuration makes it possible to reduce thermal stress generated in the plate portion of a corrugated wheel to or below the thermal stress generated in the plate portion of a non-corrugated wheel.

[0005] The corrugated wheel of Patent Document 2 is a wheel in which the rim side plate portion is located on the outer side of the raceway relative to the boss side plate portion, and the rim side plate portion is curved convexly toward the anti-flange side, while the boss side plate portion is curved convexly toward the flange side. In this corrugated wheel, the ratio of the amount of waviness of the rim side plate portion to the amount of waviness of the boss side plate portion is 1.0 or greater. The amount of waviness of the rim side plate portion is the axial distance between the curved bottom (flange-side surface) in a radial cross section at the lowest point of the waves of the plate portion and the curved bottom (flange-side surface) in a radial cross section at the highest point of the waves of the plate portion. The amount of waviness of the boss side plate portion is the axial distance between the curved bottom (anti-flange-side surface) in a radial cross section at the lowest point of the waves of the plate portion and the curved bottom (anti-flange-side surface) in a radial cross section at the highest point of the waves of the plate portion. Patent Document 2 states that the maximum thermal stress generated in the plate portion can be reduced by increasing the ratio of the amount of waviness of the rim side plate portion to the amount of waviness of the boss side plate portion.

[0006] The corrugated wheels of Patent Documents 1 and 2 can reduce the thermal stress generated in the plate portion by braking. However, Patent Documents 1 and 2 do not focus on the vibration noise generated by the wheels. Of the noise generated by railway vehicles, the vibration noise generated by contact between the rail and the wheels is called rolling noise. From the perspective of protecting the environment along railway lines, it is desirable to reduce rolling noise and improve the quietness of the wheels.

[0007] Patent Documents 3 and 4 disclose wheels for reducing noise when a railway vehicle is running. The wheel in Patent Document 3 includes an outer ring, an inner ring, and a cushion disposed between the outer ring and the inner ring. According to Patent Document 3, vibrations received by the outer ring are absorbed by the cushion, thereby reducing the transmission of vibrations to the bogie through the inner ring and axle. This reduces noise when the railway vehicle is running.

[0008] In Patent Document 4, dynamic vibrators are attached to a wheel. The dynamic vibrators are arranged on both sides of a plate portion and fixed to the inner peripheral surface of a rim portion. Each dynamic vibrator includes an active mass portion made of an annular steel piece and an elastic element interposed between the active mass portion and the wheel. This dynamic vibrator has a natural frequency equal to the resonant frequency of the wheel for a predetermined natural vibration mode, and is fixed to the rim portion so as to vibrate in the same mode as the natural vibration mode. Patent Document 4 explains that when vibrations of the rim portion are transmitted to the dynamic vibrator, the dynamic vibrator vibrates at the natural frequency of the wheel and is in tune with the wheel vibrations with an opposite phase shift, thereby attenuating the wheel vibrations and noise. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 6-278401 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-137601 [Patent Document 3] Japanese Patent Application Publication No. 2-63901 [Patent Document 4] Japanese Patent Application Publication No. 10-81104 Summary of the Invention [Problem to be solved by the invention]

[0010] Due to the corrugated shape of the plate portion, corrugated wheels tend to generate louder rolling noise than non-corrugated wheels. Possible means for improving the quietness of corrugated wheels include means for suppressing the wheel vibration itself, or means for absorbing or insulating the generated rolling noise. However, regardless of which means is selected, additional parts are usually required, as described in Patent Documents 3 and 4. Attaching additional parts to the wheel increases the manufacturing cost of the wheel and also requires maintenance of the additional parts.

[0011] An object of the present disclosure is to provide a corrugated wheel for a railway vehicle that can improve quietness without using additional parts. [Means for solving the problem]

[0012] The railway vehicle wheel according to the present disclosure comprises a boss portion, a rim portion, and a plate portion. The rim portion is disposed on the outer periphery of the boss portion. The rim portion includes a tread surface and a flange. The flange is disposed adjacent to the tread surface in the axial direction of the wheel. The flange protrudes outward from the tread surface in the radial direction of the wheel. The plate portion connects the boss portion and the rim portion. The plate portion is formed to be undulating in the circumferential direction of the wheel. The plate portion includes a first curved portion and a second curved portion. The first curved portion is curved convexly toward the flange in the axial direction. The apex of the first curved portion is disposed on the boss portion side relative to the center of the plate portion in the radial direction. The second curved portion is curved convexly toward the opposite side of the flange in the axial direction. The apex of the second curved portion is disposed on the rim portion side relative to the center of the plate portion. The wheel has a cross section with varying plate thickness. The cross section with varying plate thickness is a cross section that includes the central axis of the wheel. In the cross section of varying thickness, the thickness of the plate portion is not constant in the range from the first curved portion to the second curved portion, and the thickness is greatest at the second curved portion. [Effects of the Invention]

[0013] According to the corrugated wheel for a railway vehicle according to the present disclosure, quietness can be improved without using additional parts. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a longitudinal sectional view (first sectional view) of a wheel for a railway vehicle according to a first embodiment. [Figure 2] FIG. 2 is another vertical cross-sectional view (second cross-sectional view) of the wheel according to the first embodiment. [Figure 3] FIG. 3 is yet another vertical cross-sectional view (third cross-sectional view) of the wheel according to the first embodiment. [Figure 4] FIG. 4 is a longitudinal sectional view (second sectional view) of a wheel for a railway vehicle according to the second embodiment. [Figure 5] FIG. 5 is another vertical cross-sectional view (first cross-sectional view) of the wheel according to the second embodiment. [Figure 6] FIG. 6 is a view of yet another vertical cross section (third cross section) of the wheel according to the second embodiment. [Figure 7] FIG. 7 is a longitudinal sectional view (third sectional view) of a railway vehicle wheel according to the third embodiment. [Figure 8] FIG. 8 is another vertical cross-sectional view (first cross-sectional view) of the wheel according to the third embodiment. [Figure 9] FIG. 9 is yet another vertical cross-sectional view (second cross-sectional view) of the wheel according to the third embodiment. [Figure 10] FIG. 10 is a graph showing the improvement in quietness for each example and each comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] A railway vehicle wheel according to an embodiment includes a boss portion, a rim portion, and a plate portion. The rim portion is located on the outer periphery of the boss portion. The rim portion includes a tread surface and a flange. The flange is located adjacent to the tread surface in the axial direction of the wheel. The flange protrudes outward from the tread surface in the radial direction of the wheel. The plate portion connects the boss portion and the rim portion. The plate portion is formed to be undulating in the circumferential direction of the wheel. The plate portion includes a first curved portion and a second curved portion. The first curved portion is curved convexly toward the flange in the axial direction. The apex of the first curved portion is located on the boss portion side relative to the center of the plate portion in the radial direction. The second curved portion is curved convexly on the opposite side of the flange in the axial direction. The apex of the second curved portion is located on the rim portion side relative to the center of the plate portion. The wheel has a cross section with varying plate thickness. The cross section with varying plate thickness is a cross section that includes the central axis of the wheel. In the cross section of varying thickness, the thickness of the plate portion is not constant in the range from the first curved portion to the second curved portion, and the thickness is greatest at the second curved portion (first configuration).

[0016] Generally, noise is generated in the parts of a structure that have the least rigidity and are most susceptible to vibration. In the case of wheels for railway vehicles, the plate part has relatively low rigidity and is the main source of noise. In order to improve the quietness of the wheel, it is possible to increase the thickness of the plate part over the entire radial direction to improve the rigidity of the plate part. However, simply increasing the thickness of the plate part leads to an excessive increase in the weight of the wheel.

[0017] In contrast, the wheel according to the first configuration efficiently improves the rigidity of the plate portion formed to corrugate in the circumferential direction. Specifically, the wheel has a varying thickness cross section in which the plate portion has a non-constant thickness from the first curved portion on the boss side to the second curved portion on the rim side. In the varying thickness cross section, the plate portion has a maximum thickness at the second curved portion on the rim side. In other words, the plate portion is thickened in the region on the rim side. This allows the rim side region of the plate portion to have relatively high rigidity, and also reduces the increase in wheel weight compared to when the plate portion is thickened uniformly over the entire radial direction. Therefore, it is possible to increase the rigidity of the plate portion while taking advantage of the lightweight advantage of a corrugated wheel, thereby improving the quietness of the wheel when the railway vehicle is running.

[0018] In this way, with the wheel according to the first configuration, it is possible to efficiently increase the rigidity of the plate portion and improve quietness without using any additional parts.

[0019] In the wheel according to the first configuration, the plate thickness of the second curved portion may vary periodically along the circumferential direction (second configuration).

[0020] According to the second configuration, the thickness of the second curved portion on the rim side is not constant in the circumferential direction. That is, the area of the plate portion on the rim side is partially thickened in the circumferential direction. This makes it possible to suppress the increase in wheel weight compared to when the area of the plate portion on the rim side is thickened uniformly over the entire circumferential direction. Therefore, the rigidity of the plate portion can be increased more efficiently, improving the quietness of the wheel.

[0021] In the wheel according to the second configuration, when a cross section including the center axis of the wheel at a position where the apex of the second curved portion is closest to the flange in the axial direction is defined as a first cross section, a cross section including the center axis of the wheel at a position where the apex of the second curved portion is farthest from the flange in the axial direction is defined as a second cross section, and a cross section including the center axis of the wheel at a position midway between the first cross section and the second cross section in the circumferential direction is defined as a third cross section, at least the first cross section may be a cross section with a varying thickness. In this case, the second curved portion may have the greatest thickness in the first cross section among the first cross section, the second cross section, and the third cross section (third configuration).

[0022] Noise from the wheels is emitted in the axial direction of the wheels from the surface of the inner track or the surface of the outer track. In order to effectively reduce noise from the wheels, it is preferable to increase the thickness of the plate portion and increase the rigidity of the plate portion in the axial direction (the vibration direction of the plate portion). In a corrugated wheel whose plate portion corrugates in the circumferential direction, if the plate portion is increased in thickness at the crest or bottom of the wave, the plate portion will be thickened in the axial direction, whereas if the plate portion is increased in thickness at the middle of the wave, the plate portion will be thickened diagonally relative to the axial direction.

[0023] In the third configuration, of the first, second, and third cross sections of the wheel, at least the first cross section is a cross section with a varying thickness. The first cross section is a cross section at a position where the apex of the second curved portion on the rim side is closest to the flange side in the axial direction, in other words, a cross section when the second curved portion is located at the crest of the wave when viewed from the flange side. The second cross section is a cross section at a position where the apex of the second curved portion on the rim side is closest to the side farthest from the flange in the axial direction, in other words, a cross section when the second curved portion is located at the bottom of the wave when viewed from the flange side. The third cross section is a cross section located midway between the first and second cross sections in the circumferential direction, in other words, a cross section when the second curved portion is located in the middle of the wave.

[0024] In the third configuration, the second curved portion on the rim side has the largest thickness in the first cross section among the first, second, and third cross sections of the wheel. That is, the rim-side region of the plate portion is thickened at the crests of the waves, making it thicker in the axial direction, and the rigidity of the second curved portion on the rim side is increased in the axial direction. As a result, noise from the wheel can be effectively reduced, further improving the quietness of the wheel.

[0025] In the wheel according to the second configuration, when a cross section including the center axis of the wheel at a position where the apex of the second curved portion is closest to the flange in the axial direction is defined as a first cross section, a cross section including the center axis of the wheel at a position where the apex of the second curved portion is farthest from the flange in the axial direction is defined as a second cross section, and a cross section including the center axis of the wheel at a position midway between the first cross section and the second cross section in the circumferential direction is defined as a third cross section, at least the second cross section may be a cross section with a varying thickness. In this case, the second curved portion may have the greatest thickness in the second cross section among the first cross section, the second cross section, and the third cross section (fourth configuration).

[0026] In the fourth configuration, the second curved portion on the rim side has the largest plate thickness in the second cross section among the first, second, and third cross sections of the wheel. That is, the rim-side region of the plate portion is thickened at the bottom of the wave, making it thicker in the axial direction, and the rigidity of the second curved portion on the rim side is increased in the axial direction. As a result, noise from the wheel can be effectively reduced, further improving the quietness of the wheel.

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In these drawings, the same or equivalent components are designated by the same reference numerals, and the same description will not be repeated.

[0028] [Wheel configuration] FIG. 1 is a longitudinal cross-sectional view of a wheel 100 for a railway vehicle according to the first embodiment. The longitudinal cross-section of the wheel 100 refers to a cross-section of the wheel 100 that includes a central axis X. Because the longitudinal cross-section of the wheel 100 is symmetrical with respect to the central axis X, FIG. 1 shows only one side of the wheel 100 about the central axis X. In this embodiment, the direction in which the central axis X of the wheel 100 extends is referred to as the axial direction. Also, in this embodiment, the radial direction of the wheel 100 may be simply referred to as the radial direction.

[0029] 1, the wheel 100 is a corrugated wheel. The wheel 100 includes a boss portion 10, a rim portion 20, and a plate portion 30.

[0030] The boss portion 10 forms the inner periphery of the wheel 100. The boss portion 10 has a cylindrical shape. An axle (not shown) of a railway vehicle is inserted into the boss portion 10.

[0031] The boss portion 10 includes an inner circumferential surface 11, end faces 121 and 122, and corner portions 131 and 132. When viewed in a longitudinal cross section of the wheel 100, the inner circumferential surface 11 extends in the axial direction. When viewed in a longitudinal cross section of the wheel 100, the end faces 121 and 122 are continuous with both ends of the inner circumferential surface 11 and extend radially outward from the inner circumferential surface 11. The corner portions 131 and 132 are continuous with the end faces 121 and 122, respectively, on the opposite side of the inner circumferential surface 11.

[0032] The rim portion 20 is disposed on the outer peripheral side of the boss portion 10. The rim portion 20 constitutes the outer peripheral portion of the wheel 100. The rim portion 20 includes a tread surface 21 and a flange 22. The rim portion 20 further includes side surfaces 231, 232 and corner portions 241, 242.

[0033] The tread 21 is provided on the outer peripheral surface of the rim portion 20. The tread 21 is the surface that comes into contact with the top surface of the rail on which the railway vehicle runs. The flange 22 is disposed adjacent to the tread 21 in the axial direction of the wheel 100. The flange 22 protrudes radially outward from the tread 21. When the railway vehicle runs on the rail, the flange 22 is positioned on the inside of the left and right rails in the track width direction. Hereinafter, the side of the wheel 100 that is closer to the flange 22 in the axial direction will be referred to as the flange side, and the side that is farther from the flange 22 in the axial direction will be referred to as the anti-flange side.

[0034] In this embodiment, the rim portion 20 is positioned outward in the track width direction relative to the boss portion 10. More specifically, the rim width center Cr is located on the opposite flange side from the boss width center Cb. The rim width center Cr is the center of the rim portion 20 in the axial direction of the wheel 100. The boss width center Cb is the center of the boss portion 10 in the axial direction of the wheel 100.

[0035] The side surface 231 is provided continuous with the surface of the flange 22. When viewed in a longitudinal cross section of the wheel 100, the side surface 231 extends radially inward from the surface of the flange 22. The side surface 232 is arranged on the opposite side from the side surface 231. When viewed in a longitudinal cross section of the wheel 100, the side surface 232 extends radially inward from the end of the tread surface 21 on the opposite side to the flange 22. The corner portions 241, 242 are continuous with the side surfaces 231, 232, respectively, on the opposite sides of the tread surface 21 and the flange 22.

[0036] The plate portion 30 is annular and connects the boss portion 10 and the rim portion 20. The plate portion 30 is formed integrally with the boss portion 10 and the rim portion 20. The plate portion 30 includes curved portions 31, 32 and fillet portions 33, 34.

[0037] In a vertical cross-sectional view of the wheel 100, the curved portion 31 is curved convexly toward the flange 22 in the axial direction. The apex (curvature apex) of the curved portion 31 is located on the boss portion 10 side with respect to the center Cw of the plate portion 30 in the radial direction. The center Cw of the plate portion 30 is located midway in the radial direction between position P1 of the end portions (R-end) of the corner portions 131, 132 of the boss portion 10 on the plate portion 30 side and position P2 of the end portions (R-end) of the corner portions 241, 242 of the rim portion 20 on the plate portion 30 side. The curved portion 31 is connected to the boss portion 10 via a fillet portion 33.

[0038] The curved portion 31 includes side surfaces 311 and 312. The side surface 311 is the outer curved surface of the curved portion 31. The side surface 311 is provided continuous with a side surface 331 on the flange side of the fillet portion 33. The side surface 311 is connected to one corner portion 131 of the boss portion 10 via the side surface 331 of the fillet portion 33.

[0039] In a vertical cross-sectional view of the wheel 100, the side surface 311 of the curved portion 31 has a curved shape that convexly curves toward the flange side. In a vertical cross-sectional view of the wheel 100, the side surface 331 of the fillet portion 33 has a curved shape at least in the portion adjacent to the side surface 311 of the curved portion 31. The side surface 311 of the curved portion 31 is smoothly connected to the side surface 331 of the fillet portion 33. An inflection point exists at the boundary between the side surface 311 of the curved portion 31 and the side surface 331 of the fillet portion 33.

[0040] The side surface 312 is the surface on the inner side of the curve of the curved portion 31. The side surface 312 is arranged on the anti-flange side of the side surface 311. The side surface 312 is provided continuous with the anti-flange side side surface 332 of the fillet portion 33. The side surface 312 is connected to the other corner portion 132 of the boss portion 10 via the side surface 332 of the fillet portion 33.

[0041] In a vertical cross-sectional view of the wheel 100, the side surface 312 of the curved portion 31 has a curved shape that is convex toward the flange side. In a vertical cross-sectional view of the wheel 100, the side surface 332 of the fillet portion 33 has a curved shape at least in a portion adjacent to the side surface 312 of the curved portion 31. The side surface 312 of the curved portion 31 is smoothly connected to the side surface 332 of the fillet portion 33.

[0042] The curved portion 32 is arranged on the rim portion 20 side relative to the curved portion 31. In a longitudinal cross-sectional view of the wheel 100, the curved portion 32 is curved convexly on the opposite side of the flange 22 in the axial direction. The apex of the curved portion 32 (curvature apex) is arranged on the rim portion 20 side relative to the center Cw of the plate portion 30 in the radial direction. The curved portion 32 is connected to the rim portion 20 via the fillet portion 34.

[0043] The curved portion 32 includes side surfaces 321 and 322. The side surface 321 is the surface on the curved inner side of the curved portion 32. The side surface 321 is provided continuous with a side surface 341 on the flange side of the fillet portion 34. The side surface 321 is connected to one corner portion 241 of the rim portion 20 via the side surface 341 of the fillet portion 34.

[0044] In a vertical cross-sectional view of the wheel 100, the side surface 321 of the curved portion 32 has a curved shape that is convex toward the side opposite the flange. In a vertical cross-sectional view of the wheel 100, the side surface 341 of the fillet portion 34 has a curved shape at least in the portion adjacent to the side surface 321 of the curved portion 32. The side surface 321 of the curved portion 32 is smoothly connected to the side surface 341 of the fillet portion 34.

[0045] The side surface 321 of the curved portion 32 is also connected to the side surface 311 of the curved portion 31 on the boss portion 10 side. In this embodiment, the side surface 321 of the curved portion 32 is provided continuously with the side surface 311 of the curved portion 31. In this embodiment, an inflection point exists at the boundary between the side surface 321 of the curved portion 32 and the side surface 311 of the curved portion 31.

[0046] The side surface 322 is the curved outer surface of the curved portion 32. The side surface 322 is arranged on the anti-flange side of the side surface 321. The side surface 322 is provided continuous with the anti-flange side side surface 342 of the fillet portion 34. The side surface 322 is connected to the other corner portion 242 of the rim portion 20 via the side surface 342 of the fillet portion 34.

[0047] In a vertical cross-sectional view of the wheel 100, the side surface 322 of the curved portion 32 has a curved shape that is convex toward the side opposite the flange. In a vertical cross-sectional view of the wheel 100, the side surface 342 of the fillet portion 34 has a curved shape at least in the portion adjacent to the side surface 322 of the curved portion 32. The side surface 322 of the curved portion 32 is smoothly connected to the side surface 342 of the fillet portion 34. An inflection point exists at the boundary between the side surface 322 of the curved portion 32 and the side surface 342 of the fillet portion 34.

[0048] The side surface 322 of the curved portion 32 is also connected to the side surface 312 of the curved portion 31 on the boss portion 10 side. In this embodiment, the side surface 322 of the curved portion 32 is provided continuously with the side surface 312 of the curved portion 31. In this embodiment, an inflection point exists at the boundary between the side surface 321 of the curved portion 32 and the side surface 312 of the curved portion 31.

[0049] In the wheel 100 according to this embodiment, the plate portion 30 is formed to undulate in the circumferential direction. In this embodiment, the thickness of the curved portion 32 on the rim portion 20 side of the plate portion 30 varies periodically along the circumferential direction. On the other hand, the thickness of the curved portion 31 on the boss portion 10 side of the plate portion 30 may be substantially constant over the entire circumferential direction.

[0050] 1 shows a cross section (longitudinal cross section) S1 of the wheel 100 at the crest position of the wave of the plate portion 30 as viewed from the flange 22 side. More specifically, the cross section S1 is a cross section including the central axis X of the wheel 100 at the position where the crest of the curved portion 32 on the rim portion 20 side of the plate portion 30 is closest to the flange 22 in the axial direction.

[0051] Continuing to refer to FIG. 1, cross section S1 is a cross section of the wheel 100 where the thickness varies. That is, in cross section S1, the thickness of the plate portion 30 is not constant in a range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. The range Rw is the range in the plate portion 30 from the boundary (inflection point) between the side surface 331 of the fillet portion 33 and the side surface 311 of the curved portion 31 on the boss portion 10 side to the boundary (inflection point) between the side surface 322 of the curved portion 32 on the rim portion 20 side and the side surface 342 of the fillet portion 34. When viewed from cross section S1, the thickness of the plate portion 30 varies along its extension direction at least in the range Rw. The thickness of the plate portion 30 is the thickness of the plate portion 30 measured along the normal or perpendicular direction to the contour line of the plate portion 30.

[0052] In cross section S1, the thickness of the plate portion 30 at the curved portion 32 on the rim portion 20 side is greater than the thickness of the plate portion 30 at the curved portion 31 on the boss portion 10 side. When viewed in cross section S1, in the range Rw from curved portion 31 to curved portion 32, the thickness of the plate portion 30 is greatest at curved portion 32. In other words, there is a portion in curved portion 32 that is thicker than any other portion in curved portion 31. It is preferable that the plate portion 30 has the greatest thickness in the range Rw at least at the top of curved portion 32.

[0053] In the range Rw from the curved portion 31 to the curved portion 32, the plate portion 30 can have a minimum thickness in the curved portion 31 on the boss portion 10 side. For example, the plate portion 30 has a minimum thickness in the range Rw at least at the apex of the curved portion 31. The curved portion 31 on the boss portion 10 side may have a constant thickness (minimum thickness) in the region up to the center Cw of the plate portion 30, for example. The maximum thickness of the plate portion 30 in the range Rw is defined as t max , the minimum plate thickness is t min When the cross section S1 is max is the minimum plate thickness t min It is preferable that the thickness is 1.2 times or more, and the minimum thickness t min It is more preferable that the thickness is 1.5 times or more, and the minimum thickness t min It is more preferable that the maximum plate thickness t is 1.7 times or more. maxFor example, the minimum plate thickness t min is less than 3.0 times.

[0054] 2 is a diagram showing a cross section (longitudinal cross section) S2 of the wheel 100 at the bottom of the wave of the plate portion 30 as viewed from the flange 22 side. More specifically, the cross section S2 is a cross section including the central axis X of the wheel 100 at the position where the peak of the curved portion 32 on the rim portion 20 side of the plate portion 30 is farthest from the flange 22 in the axial direction.

[0055] In the wheel 100 according to this embodiment, the cross section S1 (FIG. 1) at the crest of the wave of the plate portion 30 is a cross section with varying thickness, while the cross section S2 at the bottom of the wave of the plate portion 30 is not a cross section with varying thickness. As shown in FIG. 2, in the cross section S2, for example, the thickness of the plate portion 30 is substantially constant in the range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. In the cross section S2, the thickness of the plate portion 30 at the curved portion 31 on the boss portion 10 side may be slightly larger than the thickness of the plate portion 30 at the curved portion 32 on the rim portion 20 side.

[0056] 3 is a diagram showing a cross section (longitudinal cross section) S3 of the wheel 100 at a position exactly midway between the crest and trough of the waves of the plate portion 30. More specifically, cross section S3 is a cross section that includes the central axis X of the wheel 100 at a position midway between cross sections S1 and S2 in the circumferential direction, that is, at a position where the angle formed with cross section S1 is equal to the angle formed with cross section S2.

[0057] In the wheel 100 according to this embodiment, in addition to the cross section S1 (FIG. 1) at the crest of the waves of the plate portion 30, the cross section S3 at the middle of the waves of the plate portion 30 is also a cross section with varying thickness. Therefore, in the cross section S3, the thickness of the plate portion 30 is not constant in the range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. Also, when viewed from the cross section S3, in the range Rw from the curved portion 31 to the curved portion 32, the thickness of the plate portion 30 is greatest at the curved portion 32 on the rim portion 20 side. It is preferable that the plate portion 30 has the greatest thickness in the range Rw at least at the crest of the curved portion 32.

[0058] However, the curved portion 32 on the rim portion 20 side has the largest thickness at the cross section S1 among the cross sections S1, S2, and S3. The cross sections S1 and S3 each have the maximum thickness t max However, the maximum thickness t of the plate portion 30 at the cross section S3 max (Fig. 3) shows the maximum thickness t of the plate portion 30 at the cross section S1. max The thickness of the curved portion 32 at the cross section S2 (FIG. 2) is smaller than the maximum thickness t of the plate portion 30 at the cross section S1 when compared at the same position in the radial direction. max and the maximum thickness t of the plate portion 30 at the cross section S3 max is smaller than.

[0059] The maximum thickness t of the cross section S1 in which the curved portion 32 on the rim portion 20 side has the maximum thickness among the cross sections S1, S2, and S3 max When compared at the same position in the radial direction, the maximum thickness t of the curved portion 32 of the cross section S2, which is the smallest among the cross sections S1, S2, and S3, is preferably 1.2 times or more, more preferably 1.5 times or more, and even more preferably 1.7 times or more. max is, for example, 3.0 times or less the thickness of the cross section S2 at the same position in the radial direction. max is t1, the thickness of the plate portion 30 at the same position in the radial direction at the cross section S2 is t2, and the maximum thickness of the plate portion 30 at the cross section S3 is t max When t3 is taken as t1, t1 / t3 is preferably different from t2 / t3. In this embodiment, t1>t3>t2, so t1 / t3 is greater than 1.0 and t2 / t3 is less than 1.0.

[0060] Although not particularly limited, such a wheel 100 can be manufactured by, for example, forging, casting, or machining (cutting) a forged or cast product. The material of the wheel 100 is preferably carbon steel.

[0061] [effect] The wheel 100 according to this embodiment is a corrugated wheel in which the plate portion 30 is formed to corrugate in the circumferential direction. The wheel 100 has cross sections S1 and S3 as cross sections where the thickness of the plate portion 30 is not constant in the range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. In each of the cross sections S1 and S3, the plate portion 30 has a maximum thickness t max and the plate portion 30 is thicker in the region on the rim portion 20 side than in the region on the boss portion 10 side. This allows the region of the plate portion 30 on the rim portion 20 side to have relatively high rigidity. Furthermore, the increase in weight of the plate portion 30 and the wheel 100 can be suppressed compared to when the plate portion 30 is thickened uniformly over the entire radial direction. Therefore, it is possible to efficiently increase the rigidity of the plate portion 30 while taking advantage of the lightweight advantage of the corrugated wheel, and to improve the quietness of the wheel 100 when the railway vehicle is running without using additional parts.

[0062] In the wheel 100 according to this embodiment, the thickness of the curved portion 32 on the rim portion 20 side of the plate portion 30 varies periodically along the circumferential direction. Specifically, the thickness of the curved portion 32 at cross section S2 is smaller than the thickness of the curved portion 32 at cross sections S1 and S3 at the same radial position. The thickness of the curved portion 32 varies in the circumferential direction, decreasing from cross section S1 to cross section S3 and then to cross section S2. That is, the thickness of the curved portion 32 decreases from the crest to the bottom of the wave of the plate portion 30 as viewed from the flange 22 side, and increases from the bottom to the next crest. This reduces the increase in weight of the plate portion 30 and the wheel 100 compared to when the thickness of the curved portion 32 on the rim portion 20 side of the plate portion 30 is increased uniformly throughout the circumferential direction. This makes it possible to more efficiently increase the rigidity of the plate portion 30 and improve the quietness of the wheel 100.

[0063] In the wheel 100 according to this embodiment, of the cross sections S1, S2, and S3, the cross section S1 at the position of the wave peak of the plate portion 30 when viewed from the flange 22 side is a cross section with varying plate thickness. That is, the curved portion 32 on the rim portion 20 side is thickened at the wave peak of the plate portion 30, and is thickened in the axial direction. In this case, the rigidity of the curved portion 32 is increased in the axial direction, in other words, in the vibration direction of the plate portion 30, so that noise from the wheel 100 can be effectively reduced. This makes it easier to improve the quietness of the wheel 100.

[0064] In the wheel 100 according to this embodiment, in the cross section of the varying plate thickness, the curvatures of the side surfaces 321, 322 of the curved portion 32 on the rim portion 20 side may be different so that the side surface 321 on the inner side of the curve is shallower than the side surface 322 on the outer side of the curve. By making the side surface 321 on the inner side of the curve shallower than the side surface 322 on the outer side of the curve, the surface area of the curved portion 32 tends to be reduced. This makes it easier to reduce noise radiated from the surface of the plate portion 30, and the quietness of the wheel 100 can be further improved.

[0065] Second Embodiment 4 to 6 are longitudinal cross-sectional views of a wheel 100A according to a second embodiment. In the wheel 100 according to the first embodiment, in the circumferentially undulating plate portion 30, the thickness of the curved portion 32 on the rim portion 20 side decreases from the wave bottom to the wave bottom when viewed from the flange 22 side, and increases from the wave bottom to the next wave bottom. On the other hand, in the wheel 100A according to the present embodiment, in the circumferentially undulating plate portion 30, the thickness of the curved portion 32 on the rim portion 20 side decreases from the wave bottom to the wave top when viewed from the flange 22 side, and increases from the wave bottom to the wave bottom. In the wheel 100A, cross sections S2 and S3 are cross sections with varying thickness, and cross section S1 is a cross section with no varying thickness.

[0066] Fig. 4 is a diagram showing a cross section (longitudinal cross section) S2 of the wheel 100A at the bottom of the wave of the plate portion 30 as viewed from the flange 22 side. Referring to Fig. 4, in the cross section S2, the thickness of the plate portion 30 is not constant in the range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. In other words, when viewed in the cross section S2, the thickness of the plate portion 30 changes along its extension direction at least in the range Rw.

[0067] In the cross section S2, the thickness of the plate portion 30 at the curved portion 32 on the rim portion 20 side is greater than the thickness of the plate portion 30 at the curved portion 31 on the boss portion 10 side. When viewed in the cross section S2, in the range Rw from the curved portion 31 to the curved portion 32, the thickness of the plate portion 30 is maximum at the curved portion 32. As in the cross section of varying thickness in the first embodiment, the plate portion 30 has a maximum thickness t max Furthermore, the plate portion 30 preferably has a minimum plate thickness t min In the cross section S2, the maximum thickness t max is the minimum plate thickness t min It is preferable that the thickness is 1.2 times or more, and the minimum thickness t min It is more preferable that the thickness is 1.5 times or more, and the minimum thickness t min It is more preferable that the maximum plate thickness t is 1.7 times or more. max For example, the minimum plate thickness t min is less than 3.0 times.

[0068] Fig. 5 is a diagram showing a cross section (longitudinal cross section) S1 of the wheel 100A at the position of the wave peak of the plate portion 30 as viewed from the flange 22 side. Referring to Fig. 5, in the cross section S1, for example, the plate thickness of the plate portion 30 is substantially constant in the range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. In the cross section S1, the plate thickness of the plate portion 30 at the curved portion 31 on the boss portion 10 side may be slightly larger than the plate thickness of the plate portion 30 at the curved portion 32 on the rim portion 20 side.

[0069] 6 is a diagram showing a cross section (longitudinal cross section) S3 of the wheel 100A at a position exactly midway between the crest and bottom of the waves of the plate portion 30. The shape of the cross section S3 of the wheel 100A according to this embodiment is the same as the shape of the cross section S3 of the wheel 100 according to the first embodiment (FIG. 3).

[0070] In the wheel 100A according to this embodiment, the curved portion 32 on the rim portion 20 side has the greatest thickness at the cross section S2 among the cross sections S1, S2, and S3. The cross sections S2 and S3 each have the maximum thickness t max However, the maximum thickness t of the plate portion 30 at the cross section S3 max (Fig. 6) shows the maximum thickness t of the plate portion 30 at the cross section S2. max The thickness of the curved portion 32 at the cross section S1 (FIG. 5) is smaller than the maximum thickness t of the plate portion 30 at the cross section S3 when compared at the same position in the radial direction. max and the maximum thickness t of the plate portion 30 at the cross section S2 max The maximum thickness t of the cross section S2, in which the curved portion 32 on the rim portion 20 side has the maximum thickness among the cross sections S1, S2, and S3, is smaller than the maximum thickness t max and the thickness (at the same position in the radial direction) of the curved portion 32 of the smallest cross section S1 among the cross sections S1, S2, and S3 can be the same as that described in the first embodiment.

[0071] The wheel 100A according to this embodiment can also achieve the same effects as the wheel 100 according to the first embodiment. In the wheel 100A according to this embodiment, of the cross sections S1, S2, and S3, the cross section S2 at the position where the wave bottom of the plate portion 30 is located when viewed from the flange 22 side is a cross section with a varying plate thickness. In other words, the curved portion 32 on the rim portion 20 side at the wave bottom of the plate portion 30 is thickened, and is made thicker in the axial direction. In this case, the rigidity of the curved portion 32 is increased in the vibration direction of the plate portion 30, and therefore noise from the wheel 100A can be effectively reduced.

[0072] Third Embodiment 7 to 9 are longitudinal cross-sectional views of a wheel 100B according to a third embodiment. In the first embodiment, the thickness of the curved portion 32 varies periodically along the circumferential direction so that the curved portion 32 on the rim portion 20 side has the greatest thickness at cross section S1 of cross sections S1, S2, and S3 of the wheel 100. In the second embodiment, the thickness of the curved portion 32 varies periodically along the circumferential direction so that the curved portion 32 on the rim portion 20 side has the greatest thickness at cross section S2 of cross sections S1, S2, and S3 of the wheel 100A. In contrast, in this embodiment, the curved portion 32 on the rim portion 20 side has the greatest thickness at cross section S3 of cross sections S1, S2, and S3 of the wheel 100B.

[0073] Fig. 7 is a diagram showing a cross section (longitudinal cross section) S3 of the wheel 100B at a position exactly midway between the crest and trough of the waves of the plate portion 30. Referring to Fig. 7, in the cross section S3, the thickness of the plate portion 30 is not constant in the range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. In other words, when viewed from the cross section S3, the thickness of the plate portion 30 varies along its extension direction at least in the range Rw.

[0074] In the cross section S3, the thickness of the plate portion 30 at the curved portion 32 on the rim portion 20 side is greater than the thickness of the plate portion 30 at the curved portion 31 on the boss portion 10 side. When viewed in the cross section S3, in the range Rw from the curved portion 31 to the curved portion 32, the thickness of the plate portion 30 is maximum at the curved portion 32. As with the cross sections of varying thickness in the other embodiments, the plate portion 30 has a maximum thickness t max Furthermore, the plate portion 30 preferably has a minimum plate thickness t min can have:

[0075] FIG. 8 is a diagram showing a cross section (longitudinal cross section) S1 of the wheel 100B at the position of the wave peak of the plate portion 30 as viewed from the flange 22 side. FIG. 9 is a diagram showing a cross section (longitudinal cross section) S2 of the wheel 100B at the position of the wave trough of the plate portion 30 as viewed from the flange 22 side. With reference to FIGS. 8 and 9, in each of the cross sections S1 and S2, for example, the plate thickness of the plate portion 30 is substantially constant in the range Rw from the curved portion 31 on the boss portion 10 side to the curved portion 32 on the rim portion 20 side. In each of the cross sections S1 and S2, the plate thickness of the plate portion 30 at the curved portion 31 on the boss portion 10 side may be slightly greater than the plate thickness of the plate portion 30 at the curved portion 32 on the rim portion 20 side. In the wheel 100B according to this embodiment, the cross section S3 is a cross section with a varying plate thickness, whereas the cross sections S1 and S2 are cross sections with no varying plate thickness. In the wheel 100B according to this embodiment, the curved portion 32 on the rim portion 20 side has the greatest thickness at cross section S3 among cross sections S1, S2, and S3.

[0076] The wheel 100B according to this embodiment can also achieve the same effects as the wheels 100 and 100A according to the other embodiments. However, when the thickness of the curved portion 32 on the rim portion 20 side varies along the circumferential direction, in order to more effectively reduce noise, it is preferable that the curved portion 32 have the greatest thickness at cross section S1 or S2 among cross sections S1, S2, and S3, as in the other embodiments.

[0077] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0078] In each of the above embodiments, the thickness of the curved portion 32 on the rim portion 20 side varies periodically along the circumferential direction. However, the thickness of the curved portion 32 may be constant along the circumferential direction. In this case, the longitudinal cross section of the wheel taken at any position in the circumferential direction will have a cross section with varying thickness. In other words, the curved portion 32 on the rim portion 20 side is thicker than the curved portion 31 on the boss portion 10 side around the entire circumference of the wheel. Even in this case, the rigidity is improved in the radial direction by targeting the portion of the plate portion 30 that contributes most to noise generation, i.e., the region on the rim portion 20 side. Therefore, compared to a case where the thickness of the plate portion 30 is uniformly increased along the entire radial direction, the quietness of the wheel can be improved while suppressing weight increase.

[0079] In the wheels 100, 100A, and 100B according to the above embodiments, the plate portion 30 typically has multiple waves along the circumferential direction. The thickness of the plate portion 30 in each wave may be the same as or different from the thickness of the plate portion 30 in the other waves. For example, if the thickness of the curved portion 32 on the rim portion 20 side varies along the circumferential direction, the change in thickness of the curved portion 32 in each wave may be different from the change in thickness of the curved portion 32 in the other waves. However, from the viewpoint of manufacturability, it is preferable that the thickness of the curved portion 32 vary in the same way in all waves.

[0080] In the wheels 100, 100A, and 100B according to the above embodiments, the rim width center Cr is located on the opposite side of the flange from the boss width center Cb. However, the rim width center Cr may be located on the flange side of the boss width center Cb. Alternatively, the rim width center Cr and the boss width center Cb may be located substantially in the same axial position. [Example]

[0081] The present disclosure will be described in more detail below with reference to examples, although the present disclosure is not limited to the following examples.

[0082] To confirm the effects of this disclosure, a finite element analysis was performed using general-purpose structural analysis software to evaluate the quietness of the wheels. In this analysis, a force simulating rail reaction force was applied to the tread of a 360° wheel model, and the response to vibration at that time was evaluated as quietness. To evaluate quietness, the equivalent radiated power (ERP) calculated using the following formula was used.

[0083]

number

[0084] In the above formula, S is the element area of the wheel surface, and V n is the vibration velocity in the normal direction of the surface. c is a coefficient determined by the state of the fluid and the analysis method. ERP is an index that indicates the ability to radiate sound (the amount of energy passing per unit time), and the larger the ERP, the greater the ability to radiate louder noise.

[0085] In this analysis, we evaluated the change in quietness caused by changing the shape of the plate part of a corrugated wheel. Table 1 shows the conditions and evaluation results for each example and comparative example. Figure 10 also shows the improvement in quietness for each example and comparative example.

[0086] [Table 1]

[0087] In Comparative Example 1, the thickness of the plate portion was generally constant in the range Rw from the curved portion on the boss side to the curved portion on the rim side. In Examples 1 to 3 and Comparative Example 2, the thickness of the plate portion was increased based on Comparative Example 1. Therefore, the weights of the wheels according to Examples 1 to 3 and Comparative Example 2 are greater than the weight of the wheel according to Comparative Example 1. The wheels according to Examples 1 to 3 and Comparative Example 2 have the same weight, but the distribution (volume distribution) of the increased thickness of the plate portion is different.

[0088] Regarding the "thickness ratio of cross section S1" in Table 1, "rim portion" refers to the ratio of the thickness at the apex of curvature on the rim portion side in cross section S1 of each example and each comparative example to the thickness at the apex of curvature on the rim portion side in cross section S1 of Comparative Example 1, and "boss portion" refers to the ratio of the thickness at the apex of curvature on the boss portion side in cross section S1 of each example and each comparative example to the thickness at the apex of curvature on the boss portion side in cross section S1 of Comparative Example 1. Similarly, regarding the "thickness ratio of cross section S2", "rim portion" refers to the ratio of the thickness at the apex of curvature on the rim portion side in cross section S2 of each example and each comparative example to the thickness at the apex of curvature on the boss portion side in cross section S2 of Comparative Example 1, and "boss portion" refers to the ratio of the thickness at the apex of curvature on the boss portion side in cross section S2 of Comparative Example 1 to the thickness at the apex of curvature on the boss portion side in cross section S2 of each example and each comparative example. Regarding the "thickness ratio of cross section S3," the "rim portion" refers to the ratio of the thickness at the apex of curvature on the rim portion side in cross section S3 of each example and comparative example to the thickness at the apex of curvature on the rim portion side in cross section S3 of comparative example 1, and the "boss portion" refers to the ratio of the thickness at the apex of curvature on the boss portion side in cross section S3 of each example and comparative example to the thickness at the apex of curvature on the boss portion side in cross section S3 of comparative example 1. When these values exceed 1.00, this means that the thickness of the plate portion at the specified location on the specified cross section is thicker than in comparative example 1, and when these values are 1.00, this means that the thickness of the plate portion at the specified location on the specified cross section is the same as in comparative example 1.

[0089] In Table 1, the "S1 / S3 ratio" is the ratio of the thickness of the apex of curvature on the rim side at cross section S1 to the thickness of the apex of curvature on the rim side at cross section S3 in each of the examples and comparative examples. Similarly, the "S2 / S3 ratio" is the ratio of the thickness of the apex of curvature on the rim side at cross section S2 to the thickness of the apex of curvature on the rim side at cross section S3 in each of the examples and comparative examples.

[0090] The "amount of quietness improvement" in Table 1 and FIG. 10 is calculated for each example and each comparative example by converting the above-mentioned ERP(W) into L using the following formula: ERP (dB) and calculated the difference from Comparative Example 1. ERP is the equivalent radiated power level, ERP0 is the reference value of the equivalent radiated power (=10-12 (W)). The larger the positive value of the improvement in quietness, the more quietness is improved.

[0091]

number

[0092] Example 1 corresponds to the first embodiment (FIGS. 1 to 3). In Example 1, cross sections S1 and S3 are cross sections with varying thickness, and in each of cross sections S1 and S3, the plate portion has the maximum thickness at the apex of the curved portion on the rim portion side in the range Rw from the curved portion on the boss portion side to the curved portion on the rim portion side. However, as can be seen from the "Thickness ratio of cross section S1" and the "Thickness ratio of cross section S3" in Table 1, the curved portion on the rim portion side of the plate portion has the greatest thickness increase in cross section S1.

[0093] Example 2 corresponds to the third embodiment (FIGS. 7 to 9). In Example 2, cross section S3 is a cross section of varying thickness, and in cross section S3, the plate portion has a maximum thickness at the apex of the curved portion on the rim portion side in the range Rw from the curved portion on the boss portion side to the curved portion on the rim portion side.

[0094] Example 3 corresponds to the second embodiment (FIGS. 4 to 6). In Example 3, cross sections S2 and S3 are cross sections with varying thickness, and in each of cross sections S2 and S3, the plate portion has the maximum thickness at the apex of the curved portion on the rim portion side in the range Rw from the curved portion on the boss portion side to the curved portion on the rim portion side. However, as can be seen from the "Thickness ratio of cross section S2" and the "Thickness ratio of cross section S3" in Table 1, the curved portion on the rim portion side of the plate portion has the greatest thickness increase in cross section S2.

[0095] Comparative Example 2 is obtained by uniformly increasing the thickness of the plate portion of Comparative Example 1. That is, Comparative Example 2 does not have any cross sections where the plate thickness varies, and in all of cross sections S1, S2, and S3, the plate thickness of the plate portion is roughly constant in the range Rw from the curved portion on the boss side to the curved portion on the rim side.

[0096] As shown in Table 1 and Fig. 10, even in Comparative Example 2, quietness was improved compared to Comparative Example 1. However, in Examples 1 to 3, in which at least one of the cross sections S1, S2, and S3 is a thickness-varying cross section and the curved portion on the rim side of the thickness-varying cross section is thickened, quietness was further improved compared to Comparative Example 2. It was confirmed that quietness was particularly improved in Example 1, in which the cross section S1 is a thickness-varying cross section, and Example 3, in which the cross section S2 is a thickness-varying cross section. The improvement in quietness was greatest in Example 1, in which the cross section S1 is a thickness-varying cross section.

[0097] As shown in Table 1, in Example 1 and Example 3, the value of the "S1 / S3 ratio" and the value of the "S2 / S3 ratio" are different. On the other hand, in Example 2, the value of the "S1 / S3 ratio" and the value of the "S2 / S3 ratio" are equal. Since Examples 1 and 3 showed a greater improvement in quietness than Example 2, when the plate thickness of the curved portion on the rim side of the plate portion is changed along the circumferential direction, it is preferable to change the plate thickness so that the "S1 / S3 ratio" ≠ "S2 / S3 ratio." [Explanation of symbols]

[0098] 100,100A,100B: Wheel 10: Boss Section 20: Rim 21: Tread 22: Flange 30: Board part 31: First curved section 32: Second curved section S1: 1st cross section S2: 2nd cross section S3: 3rd cross section X: Central axis

Claims

1. A wheel for a railway vehicle, Boss section and a rim portion disposed on the outer circumferential side of the boss portion and including a tread surface and a flange provided adjacent to the tread surface in the axial direction of the wheel and protruding outward from the tread surface in the radial direction of the wheel; a plate portion that connects the boss portion and the rim portion and is formed to be wavy in the circumferential direction of the wheel; Equipped with The plate portion is a first curved portion that is curved convexly toward the flange in the axial direction and has an apex that is located toward the boss portion with respect to a center of the plate portion in the radial direction; a second curved portion that is curved convexly toward the opposite side of the flange in the axial direction and has an apex that is located on the rim portion side with respect to the center of the plate portion; Including, The wheel has a cross section including a central axis of the wheel, in which the thickness of the plate portion is not constant in the range from the first curved portion to the second curved portion, and the thickness is greatest at the second curved portion.

2. 2. A wheel according to claim 1, A wheel, wherein the plate thickness of the second curved portion varies periodically along the circumferential direction.

3. 3. A wheel according to claim 2, When a cross section including the central axis of the wheel at a position where the apex of the second curved portion is closest to the flange in the axial direction is defined as a first cross section, a cross section including the central axis of the wheel at a position where the apex of the second curved portion is farthest from the flange in the axial direction is defined as a second cross section, and a cross section including the central axis of the wheel at a position intermediate between the first cross section and the second cross section in the circumferential direction is defined as a third cross section, at least the first cross section is the plate thickness changing cross section, The second curved portion has a maximum thickness in the first cross section among the first cross section, the second cross section, and the third cross section.

4. 3. A wheel according to claim 2, When a cross section including the central axis of the wheel at a position where the apex of the second curved portion is closest to the flange in the axial direction is defined as a first cross section, a cross section including the central axis of the wheel at a position where the apex of the second curved portion is farthest from the flange in the axial direction is defined as a second cross section, and a cross section including the central axis of the wheel at a position intermediate between the first cross section and the second cross section in the circumferential direction is defined as a third cross section, at least the second cross section is the plate thickness changing cross section, The second curved portion has a maximum plate thickness in the second cross section among the first cross section, the second cross section, and the third cross section.

Images