Railway wheel with low deformation

Abstract

Railway wheel with low deformation. Railway wheel (2) having a rim (4), a hub (6) and spokes (8) connecting the rim (4) to the hub (6), the spokes (8) being connected to the rim (4) by a first connection area (14) and to the hub (6) by a second connection area (16), the spokes (8) extending along a meridian (L) extending between a first point (A) at the junction between the spoke (8) and the first connection area (14) and a second point (B) at the junction between the spoke (8) and the second connection area (16), the meridian (L) defining a non-zero angle between a tangent (TA) to the meridian (L) at the first point (A) and a tangent (TB) to the meridian (L) at the second point (B).

Description

Technical Field

[0001] The present invention relates to a railway wheel with small deformation, particularly when the railway wheel is braked with brake shoes. Background Technology

[0002] These railway wheels can be used in heavy-duty freight railway vehicles or in high-speed railway vehicles. High-speed railway vehicles can typically travel at speeds exceeding 200 km / h.

[0003] Railway wheels typically consist of a rim, a hub, and spokes that connect the rim and hub. The rim usually has a wheel tread and side guide flanges.

[0004] Railway wheels are used to mount on axle positioning support surfaces by their hubs, and travel on the rails via the wheel treads of their rims. The flanges of the rims contact the sides of the rails to ensure lateral guidance of the railway wheels when changing routes and when on guard rails.

[0005] The braking of railway wheels can be ensured by means of brake shoes that are in contact with the wheel rim. The brake shoes are made of metal braking materials or composite materials.

[0006] The mechanical stress and thermal expansion generated in railway wheels due to continuous braking cause the spokes to deform, a process known as déjettement. This deformation changes the axial position of the rim relative to the hub, causing the distance between the rims of two wheels on the same axle to increase or decrease depending on the wheel geometry.

[0007] When deformation reduces the rim spacing, track equipment such as turnouts becomes difficult to pass through; if the deformation is too great, it can lead to derailment. Therefore, a wheel geometry that tends to separate the rims under braking is generally preferred.

[0008] When deformation causes the rim spacing to increase, it tends to cause the rim flange to rub against the side of the rail, thus causing additional wear.

[0009] In both cases, to avoid difficulties caused by excessive deformation, the heat load on the axle should be limited to prevent the wheels from generating heat during operation.

[0010] This is especially true on railway lines where the terrain requires long braking distances, such as those traversing mountain valleys.

[0011] Deformation includes thermal deformation present during braking, residual deformation that continues after the railway wheel cools down, and residual deformation caused by permanent deformation due to heat generation.

[0012] In addition, continuous heating will generate a large residual tensile stress field in the railway wheel, which will limit the running performance of the railway wheel due to the expansion of surface fatigue defects.

[0013] Document EP0798136A1 proposes a railway wheel whose spokes extend along a curved meridian, which extends between a first point and a second point located on both sides of a mid-plane passing through half the thickness of the rim and symmetrical with respect to the intersection of the meridian and the mid-plane, the intersection being the inflection point of the meridian. The tangents of the meridian at the first and second points are approximately parallel to the mid-plane.

[0014] In terms of limiting deformation using the braking devices used to date, this railway wheel provides satisfactory results. The braking devices generally have brake shoes made of metal that can dissipate some of the heat, thereby limiting the heat generation of the railway wheel.

[0015] However, the new braking devices will use brake shoes made of composite materials. Composite materials do not have the same thermal conductivity as metals, so the brake shoes will release less heat during braking. As a result, the railway wheels will experience greater heat generation during braking, which will increase the deformation of the railway wheels and increase the residual tensile stress of the railway wheels. Summary of the Invention

[0016] One of the objectives of this invention is to provide a railway wheel that has low sensitivity to thermal and residual deformation, low residual tensile stress level, and maintains good thermomechanical properties.

[0017] Therefore, the present invention proposes a railway wheel having a rotational shape about a central axis perpendicular to a mid-plane. The railway wheel has a rim, a hub, and spokes connecting the rim to the hub. Half the thickness of the rim is located in the mid-plane. The rim has a wheel tread and side guide flanges. The spokes are connected to the rim by a first connecting region and to the hub by a second connecting region. The spokes extend along a meridian, which extends between a first point where the spokes and the first connecting region meet and a second point where the spokes and the second connecting region meet. A non-zero angle is defined between the tangent of the meridian at the first point and the tangent of the meridian at the second point.

[0018] The non-zero angle between the tangents of the meridian at the first point and the tangents at the second point allows for the design of a railway wheel that maintains satisfactory thermomechanical characteristics (stiffness, flexibility, mechanical properties, mechanical strength) while limiting deformation (thermal deformation and / or residual deformation), especially achieving a rim that facilitates heat dissipation from the rim during braking and a first connection area between the spokes and the rim.

[0019] According to some specific embodiments, railway wheels have one or more of the following optional features, selected individually or in combination of all technically feasible options:

[0020] - The angle between the tangent of the meridian at the first point and the mid-plane is defined as between 22° and 37°;

[0021] - The tangent to the meridian at the second point is approximately parallel to the mid-plane;

[0022] - The first and second points are located on opposite sides of the mid-plane, with the first point and the side guide rim on the same side of the mid-plane;

[0023] - The meridian has an inflection point between the first and second points, and the inflection point is on the same side of the mid-plane as the first point;

[0024] -The railway wheels are roughly centered;

[0025] - A railway wheel has a first surface and a second surface, a side guide flange located on the first surface side, a rim having a first inner diameter on the first surface side, and a rim having a second inner diameter on the second surface side, the ratio of the first inner diameter to the second inner diameter being between 0.96 and 1.12;

[0026] - The distance between the midline and the third point of the meridian is between 38 mm and 65.5 mm. The third point is located on the same side of the midline as the first point and is the furthest point from the midline.

[0027] The present invention also relates to a railway vehicle bogie having at least one railway wheel as described above.

[0028] The present invention also relates to a railway vehicle having at least one railway wheel as described above. Attached Figure Description

[0029] The invention and its advantages will be better understood by reading the following description, which is given with reference to the accompanying drawings and is by way of non-limiting example only, in which:

[0030] Figure 1 It is a half-view cross-section of a railway wheel; and

[0031] Figure 2 This is a half-view cross-section of another railway wheel. Detailed Implementation

[0032] Figure 1 The railway wheel 2 shown has a general rotational shape around the central axis X-X', and the railway wheel has a rim 4, a hub 6, and spokes 8 that ensure the connection between the rim 4 and the hub 6.

[0033] Preferably, the railway wheel 2 is made of a single material. Therefore, the rim 4, hub 6, and spokes 8 are integrally formed. The railway wheel 2 is, for example, forged or molded.

[0034] The railway wheel 2 has two opposite surfaces, namely the first surface 2A and the second surface 2B.

[0035] The first surface 2A is arranged facing another railway wheel that is coaxial with the railway wheel 2 and forms an axle with it, and the second surface 2B is arranged facing the opposite direction to the other railway wheel.

[0036] The rim 4 has a wheel tread 10 and a rim 12.

[0037] The wheel tread 10 is the surface of the wheel rim 4 that the wheel rim 4 passes over when it is in operation and rolls on the railway rail.

[0038] The flange 12 is located on one edge of the rim 4 and on the first surface 2A side of the railway wheel 2. The flange 12 is used to ensure lateral guidance of the railway wheel 2 relative to the railway rail by contacting the side of the railway rail on which the railway wheel 2 rolls.

[0039] The rim 4 has a first side 4A and a second side 4B. The first side 4A and the second side 4B are located on the first surface 2A and the second surface 2B of the railway wheel 2, respectively.

[0040] Preferably, the first side 4A and the second side 4B of the rim 4 are generally planar and perpendicular to the central axis X-X'.

[0041] The rim 4 has a thickness E measured along the central axis X-X' between the first side 4A and the second side 4B of the rim 4.

[0042] The railway wheel 2 has a center plane P perpendicular to the center axis X-X' and passing through half the thickness of the rim 4. The center plane P is equidistant from the first side 4A and the second side 4B of the rim 4.

[0043] The hub 6 has two axial ends, namely a first axial end 6A located on the first surface 2A side of the railway wheel 2, and a second axial end 6B located on the second surface 2B side of the railway wheel 2.

[0044] The spoke 8 is connected to the rim 4 by the first connecting area 14 and to the hub 6 by the second connecting area 16.

[0045] The first connecting region 14 and the second connecting region 16 each ensure a gradual transition between the spoke 8 and the rim 4 and the hub 6, respectively, to ensure good mechanical performance, especially to limit stress concentration.

[0046] The spokes 8, the first connecting region 14, and the second connecting region 16 define a first side surface 18A on a first surface 2A of the railway wheel 2 and a second side surface 18B on a second surface 2B of the railway wheel 2.

[0047] The first side surface 18A is located on the side of the first surface 2A and extends along the spoke 8 and the first and second connecting regions 14 and 16. The second side surface 18B is located on the side of the second surface 2B and extends along the spoke 8 and the first and second connecting regions 14 and 16.

[0048] The first side surface 18A and the second side surface 18B each extend from the rim 4 to the hub 6.

[0049] like Figure 1 As shown, in the plane containing the central axis X-X' of the railway wheel 2 (e.g. Figure 1 On a half-section of the plane, the spokes 8 extend along the meridian L between a first point A and a second point B. The spokes 8 engage the first connecting region 14 at the first point A and the second connecting region 16 at the second point B.

[0050] The spokes 8 have a thickness e that is measured perpendicular to the meridian L.

[0051] Preferably, as the wheel moves from the hub 6 to the rim 4, the thickness e of the spoke 8 gradually decreases monotonically along the meridian L.

[0052] This maintains good mechanical properties while reducing the weight of the spokes 8, thus reducing the overall weight of the wheel 2.

[0053] Meridian L is a curve.

[0054] This allows the spokes 8 to have a certain degree of flexibility while maintaining good mechanical properties.

[0055] Point A and point B are located on opposite sides of the midplane P.

[0056] Preferably, the first point A and the rim 12 are located on the same side of the midplane P, and the second point B is located on the opposite side. The first point A is offset relative to the midplane P on the first surface 2A side, and the second point B is offset relative to the midplane P on the second surface 2B side.

[0057] Meridian L intersects the midplane P, extends between the first point A and the midplane P, lies on the side of the first surface 2A relative to the midplane P, and extends between the midplane P and the second point B, lies on the side of the second surface 2B relative to the midplane P.

[0058] Meridian L has, for example, an inflection point I between the first point A and the second point B, preferably only one inflection point I between the first point A and the second point B.

[0059] Inflection point I is offset relative to the midplane P, for example. Therefore, inflection point I does not belong to the midplane P. Preferably, inflection point I and the first point A are located on the same side relative to the midplane P, particularly on the side of the first surface 2A.

[0060] Moving radially along the spokes 8, the first side surface 18A and the second side surface 18B of the wheel 2 are curved, along the meridian L between the first point A and the second point B.

[0061] The first side surface 18A and the second side surface 18B have opposite curvatures at each point along the meridian L: when the first side surface 18A is concave at a point along the meridian L, the second side surface 18B is convex at the same point, and vice versa; when the first side surface 18A is convex at a point along the meridian L, the second side surface 18B is concave at the same point.

[0062] As shown in the embodiment, when points A and B are located on the first side surface 18A and the second side surface 18B respectively relative to the midplane P, and when the meridian L has only one inflection point I, between point A and inflection point I, the first side surface 18A is convex and the second side surface 18B is concave, and between inflection point I and the second point B, the first side surface 18A is concave and the second side surface 18B is convex.

[0063] In each connecting region 14, 16, the curvature of the first side surface 18A and the second side surface 18B is of the same type. More precisely, in each connecting region 14, 16, both the first side surface 18A and the second side surface 18B are concave. This allows for a gradual and rapid increase in the thickness of the wheel 2 in the connecting regions 14, 16.

[0064] Preferably, from the rim 4 to the hub 6, that is, successively on the first connecting region 14, the spoke 8 and the second connecting region 16, the first side surface 18A and the second side surface 18B are each curved and have basically no sharp edges or breaks.

[0065] Therefore, when passing through the meridian L in the direction of the rim 4, the first point A is located near the rim 4, at the part where the first side surface 18A and the second side surface 18B change from having different types of curvature (convex / concave) to both having concave configurations. When passing through the meridian L in the direction of the hub 6, the second point B is located near the hub 6, at the part where the first side surface 18A and the second side surface 18B change from having different types of curvature (convex / concave) to both having concave configurations.

[0066] As shown in the embodiment, when points A and B are located on the side of the first surface 2A and the second surface 2B respectively relative to the midplane P, and when the meridian L has a single inflection point I, when passing through the meridian L in the direction towards the rim 4, the first point A is located on the first surface 2A, particularly its first side surface 18A, where an inflection point is formed, changing from a convex shape to a concave shape. When passing through the meridian L in the direction along the hub 6, the second point B is located on the second surface 2B, particularly its second side surface 18B, where an inflection point is formed, changing from a convex shape to a concave shape.

[0067] Meridian L has a first tangent TA at a first point A and a second tangent TB at a second point B.

[0068] In one embodiment, a non-zero angle is formed between the first tangent TA and the second tangent TB. Therefore, the first tangent TA and the second tangent TB are not parallel to each other.

[0069] In one embodiment, the first tangent TA forms a non-zero angle α with the midplane P. The second tangent TA is not parallel to the midplane P. Preferably, the angle α is between 22° and 37°. Figure 1 On the railway wheel 2, there is an angle α of approximately 22°.

[0070] The second tangent TB is approximately perpendicular to the axis X-X'. The second tangent is approximately parallel to the midplane P.

[0071] Preferably, among the points on the second surface 2B side of the segment of meridian L relative to the midplane P, the second point B is furthest from the midplane P.

[0072] Meridian L extends from its intersection with the midplane P toward the second point B, gradually moving away from the midplane P until it reaches the second tangent TB.

[0073] On the first surface 2A side relative to the midplane P, the meridian L passes through a third point C, which is located between the intersection of the meridian L and the midplane P and the first point A. The meridian L has a third tangent TC at the third point C that is parallel to the midplane P.

[0074] The third point C is the point on the meridian L located on the side of the first surface 2A relative to the midplane P, and it is furthest from the midplane P.

[0075] On the first surface 2A side, starting from the intersection of the meridian and the central plane P, the meridian L gradually moves away from the central plane P until the third point C, and then gradually approaches the central plane P until the first point A.

[0076] This shape of the spokes 8 allows for the attainment of the desired angle α, resulting in satisfactory thermomechanical characteristics, particularly the thermomechanical characteristics of the spokes 8 in terms of flexibility and strength.

[0077] The distance between the first point A and the midplane P is strictly less than the distance between the third point C and the midplane P.

[0078] Advantageously, the distance d3 between the third point C and the midplane P, measured along the central axis X-X', is between 38 mm and 65.5 mm. This maximum offset value of the spoke 8 relative to the midplane P on the first surface 2A side allows for the acquisition of the desired thermomechanical characteristics.

[0079] In one embodiment, the distance d1 between the first point A and the midplane P is between 21 mm and 37 mm, and / or the distance d2 between the second point B and the midplane P is 97.8 mm.

[0080] The rim 4 has a first inner diameter DA on the first surface 2A and a second inner diameter DB on the second surface 2B.

[0081] The first inner diameter DA is the diameter of the inner circular edge of the first side 4A of the rim 4, and the second inner diameter DB is the diameter of the inner circular edge of the second side 4B of the rim 4.

[0082] Preferably, the ratio r of the first inner diameter DA to the second inner diameter DB is between 0.96 and 1.12. Following this ratio r, satisfactory thermomechanical properties can be obtained.

[0083] It should be noted that the first inner diameter DA can be smaller than the second inner diameter DB (r is less than 1), larger than the second inner diameter DB (r is greater than 1), or equal to the second inner diameter DB (r is equal to 1).

[0084] exist Figure 1 In the embodiment shown, the first inner diameter DA is strictly smaller than the second inner diameter DB, such that the ratio r of the first inner diameter DA to the second inner diameter DB is strictly less than 1.

[0085] The rim 4 is in a new state of the wheel, for example, having a nominal diameter D, which is between 650 mm and 1000 mm. The nominal diameter D is measured between the centerline X-X' and the intersection of the wheel tread 10 of the rim 4 and the center plane P.

[0086] The offset distance DL of the rim 4 relative to the hub 6 on the first surface 2A side of the railway wheel 2 (i.e., the axial distance measured along the central axis X-X' between the first side surface 4A of the rim 4 and the first axial end 6A of the hub 6) can affect the deformation of the railway wheel 2.

[0087] Preferably, the lateral offset distance DL is between -45 mm and 145 mm. Typically, the lateral offset distance DL is negative when the first side surface 4A of the rim 4 is axially offset relative to the first axial end 6A on the opposite side of the second axial end 6B. The lateral offset distance DL is positive when the first side surface 4A of the rim 4 is axially offset relative to the first axial end 6A of the hub 6 on the side of the second axial end 6B. Figure 1 Above, the lateral offset distance DL is positive.

[0088] Retaining numerical labels Figure 2 The railway wheel 2 shown is Figure 1The difference in the railway wheel 2 shown is that the angle α is larger; and the second inner diameter DB is strictly smaller than the first inner diameter DA, such that the ratio r is strictly greater than 1. Here, the angle α is approximately 37°.

[0089] Figure 1 and 2 The two geometries shown are two specific geometries that define the geometry that yields good braking performance. Therefore, a wheel can have either of these two geometries.

[0090] Therefore, preferably, the angle α is between 22° and 37°, such as Figure 1 and Figure 2 As shown in the figures. This means that, on the railway wheel 2 according to the invention, angle α can be taken as... Figure 1 The angle value shown is the same as Figure 2 Any value between the angle values ​​shown.

[0091] in particular, Figure 1 and 2 The diagram shows two specific geometries for the spokes, which can be achieved using... Figure 1 The geometry shown is Figure 2 Any geometry between the given geometry.

[0092] The shape and size of the railway wheel 2 according to the invention allow for satisfactory thermomechanical characteristics, limiting the railway wheel's sensitivity to deformation, whether involving thermal deformation or residual deformation.

[0093] The shape of the spokes 8 achieves satisfactory flexibility and mechanical properties, while allowing for the design of a connection area that optimizes heat flow distribution within the railway wheel 2 when braking with the brake shoes against the rim 4. Therefore, using brake shoes made of composite materials makes it possible to limit the risk of overheating of the rim 4 and excessive deformation of the railway wheel 2. It also allows for adherence to noise constraints, limiting emitted noise, particularly during braking.

Claims

1. Railway wheel (2) having a revolution shape about a median axis (X-X') perpendicular to a median plane (P), having opposite first (2A) and second (2B) surfaces, having a rim (4) with a half-thickness lying in the median plane (P), having a wheel tread (10) and a lateral guide flange (12) on the side of the first surface (2A), having a web (8) connecting the rim (4) by a first connecting area (14) and connecting the hub (6) by a second connecting area (16), the web (8) and the first and second connecting areas (16) defining a first lateral surface (18A) on the first surface (2A) and a second lateral surface (18B) on the second surface (2B), the web (8) extending along a meridian line (L) extending between a first point (A) at the junction between the web (8) and the first connecting area (14) and at the point where the first and second lateral surfaces (18A, 18B) change from a configuration in which they are of different types to a configuration in which they are both concave, and a second point (B) at the junction between the web (8) and the second connecting area (16) and at the point where the first and second lateral surfaces (18A, 18B) change from a configuration in which they are of different types to a configuration in which they are both concave, the rim (4) having a first inner diameter (DA) on the side of the first surface (2A) and a second inner diameter (DB) on the side of the second surface (2B), the meridian line (L) defining a non-zero angle between a tangent (TA) to the meridian line (L) at the first point (A) and a tangent (TB) to the meridian line (L) at the second point (B), the tangent (TA) to the meridian line (L) at the first point (A) defining an angle with the median plane (P) comprised between 22° and 37°, the ratio between the first inner diameter (DA) and the second inner diameter (DB) being comprised between 0.96 and 1.

12.

2. The railway wheel of claim 1, wherein, The tangent to the meridian line (L) at the second point (B) is substantially parallel to the median plane (P).

3. Railway wheel according to claim 1 or 2, wherein The first point (A) and the second point (B) are on opposite sides of the median plane (P), the first point (A) being on the same side of the median plane (P) as the lateral guide flange (12).

4. The railway wheel of claim 1, wherein, The meridian line (L) has an inflection point (I) between the first point (A) and the second point (B), the inflection point (I) being on the same side of the median plane (P) as the first point (A).

5. The railway wheel of claim 1, wherein, The railway wheel (2) is substantially centred.

6. The railway wheel of claim 1, wherein, On the side of the first surface (2A) with respect to the median plane (P), the meridian line (L) passes through a third point (C) between the intersection of the meridian line (L) with the median plane (P) and the first point (A), the meridian line having a third tangent (TC) to the median plane (P) at the third point (C).

7. The railway wheel of claim 6, wherein, The third point (C) is the point of the meridian line (L) on the side of the first surface (2A) with respect to the median plane (P) furthest from the median plane (P).

8. The railway wheel of claim 1, wherein, The distance between the median plane (P) and a third point (C) of the meridian (L) is comprised between 38 mm and 65.5 mm, the third point being on the same side of the median plane (P) as the first point (A) and being the most distant from the median plane (P).

9. The railway wheel of claim 1, wherein, Among the points of the meridian (L) on the section of the meridian (L) on the side of the second surface (2B) relative to the median plane (P), the second point (B) is the most distant from the median plane (P).

10. The railway wheel of claim 1, wherein, The meridian (L) is a curve.

11. The railway wheel of claim 1, wherein, The thickness (e) of the spoke (8) monotonously decreases along the meridian (L) when moving from the hub (6) towards the rim (4).

12. The railway wheel of claim 1, wherein, The distance (d1) between the first point (A) and the median plane (P) is comprised between 21 mm and 37 mm.

13. The railway wheel of claim 1, wherein, The rim (4) has a lateral offset distance (DL) comprised between -45 mm and 145 mm.

14. A railway car truck, wherein, The railway vehicle bogie has at least one railway wheel according to claim 1.

15. A railway vehicle, wherein, The railway vehicle has at least one railway wheel according to claim 1.

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