Bogie and bogie frame with asymmetric support beams for a rail vehicle

Abstract

A monocoque bogie frame (14) for a bogie (10) of a railway vehicle, comprising two side beams (24) and at least one support beam (28) extending in a transverse direction of the bogie frame (14) and rigidly connected to each of the two side beams (24). The support beam (28) comprises a support portion (30) for supporting a drive unit (16) of the bogie (10) and an elongated portion (32). The support portion (28) is directly connected to one of the two side beams (14) and connected to the other one of the two side beams (14) via the elongated portion (32). The planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the support portion (30) of the support beam (28) are at least twice, preferably at least 2.5 times, the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the elongated portion (32) of the support beam (28), respectively.

Description

TECHNICAL FIELD

[0001] The present invention relates to a bogie frame and a bogie for a railway vehicle, in particular a motor bogie. BACKGROUND

[0002] The primary suspension between the wheel bearing and the bogie frame plays an important role in compensating for track irregularities. The primary suspension has to be soft enough to cope with track twist and to avoid wheel load reduction.

[0003] To achieve similar rolling performance, an inner side bearing bogie with a narrow primary spring spacing requires a stiffer primary spring than an outer side bearing bogie frame. To compensate for the increased spring stiffness, a soft bogie frame with twist is advantageous. However, a soft structure of the bogie frame can conflict with other functions of the bogie frame, in particular in case of a motor bogie which has to support a drive unit comprising a motor and / or a gearbox.

[0004] Articulated bogie frames have been developed (e.g. as disclosed in US 9096240) to overcome wheel load reduction due to track twist. Such articulated bogie frames comprise at least two parts (or half frames) which are connected and articulated relative to each other about a pivot axis, more specifically about a horizontal transversal or longitudinal pivot axis. However, such articulated bogie frames are complex structures which require specific and costly maintenance of the pivot between the articulated parts of the bogie.

[0005] Therefore, there is a need for a motor bogie which combines good rolling performance and good compensation of track irregularities. SUMMARY

[0006] According to a first aspect of the present invention, there is provided a monolithic bogie frame for a bogie of a railway vehicle, the monolithic bogie frame comprising:

[0007] at least two side beams which extend in a longitudinal direction of the bogie frame and which are spaced apart from each other in a transversal direction of the bogie frame, respectively on a left side and on a right side of a longitudinal midplane of the bogie frame; and

[0008] at least one support beam which extends in the transversal direction of the bogie frame, wherein the support beam is rigidly connected to each of the two side beams and comprises a support portion for supporting a drive unit of the bogie and an elongated portion, wherein each cross section of the support beam has a planar moment of inertia M and a polar moment of inertia J by a cross section plane parallel to the longitudinal midplane,

[0009] The support portion is directly connected to one of the two side beams and connected to the other of the two side beams via the elongated portion, wherein the planar moment of inertia M and the polar moment of inertia J of any cross section of the support portion of the support beam are at least twice, preferably at least 2.5 times, the planar moment of inertia M and the polar moment of inertia J of any cross section of the elongated portion of the support beam.

[0010] The bogie frame is in a sense monolithic, as it is not composed of articulated parts. The bogie frame is designed as a torsionally flexible structure to accommodate large deformations at the primary suspension on a twisted track. The stiffer support portions of the bogie frame allow for rigid support of the drive units, while the thinner elongated portions provide reduced stiffness of the bogie frame. The design of the non-uniform support beam enables local deformation of the elongated portions, which allows the frame to displace more freely when supporting the gearbox loads.

[0011] The support portion is preferably provided with a support interface, which can comprise one or more through holes for insertion of connecting elements for mounting the drive units.

[0012] To distribute torsional and bending stresses evenly in the softer regions of the support beam, the length of the elongated portion extending in the transverse direction is at least one third, and preferably at least two fifths, of the total length of the support beam measured in the transverse direction from one of the side beams to the other. Preferably, the length of the support portion extending in the transverse direction is less than two fifths, and preferably less than one third, of the total length of the support beam measured in the transverse direction from one of the side beams to the other.

[0013] To avoid stress concentrations, the support beam further comprises a transition portion extending from the support portion to the elongated portion, wherein the planar moment of inertia M and the polar moment of inertia J of any cross section of the transition portion decrease as the distance of the cross section to the support portion increases.

[0014] In one embodiment, the polar moment of inertia J of any cross section of the support portion of the support beam is at least three times the polar moment of inertia J of any cross section of the elongated portion of the support beam.

[0015] In a preferred embodiment, the monocoque bogie frame comprises a further support beam extending in the transverse direction of the monocoque bogie frame, wherein the support beam and the further support beam are spaced apart from each other in the longitudinal direction of the monocoque bogie frame on a front side and a rear side, respectively, of the transverse midplane of the monocoque bogie frame, wherein the further support beam comprises a further support portion for supporting a drive unit or a further drive unit and a further elongated portion connecting the further support portion to one of the two side beams and directly to the other one of the two side beams, wherein each cross section of the further support beam has a planar moment of inertia M and a polar moment of inertia J through a cross-sectional plane parallel to the longitudinal midplane, and the planar moment of inertia M and the polar moment of inertia J of any cross section of the further support portion of the further support beam are at least twice as large, respectively, as the planar moment of inertia M and the polar moment of inertia J of any cross section of the further elongated portion of the further support beam.

[0016] In various embodiments, one or more of the following conditions is met:

[0017] The support portion and the further support portion are located on opposite sides of the longitudinal midplane of the monocoque bogie frame,

[0018] The support beam and the further support beam are symmetric or substantially symmetric with respect to a vertical intersection axis between the longitudinal midplane and the transverse midplane of the monocoque bogie frame,

[0019] The support beam is closer to an end of the monocoque bogie frame than to the transverse midplane,

[0020] The further support beam is closer to a further end of the monocoque bogie frame than to the transverse midplane,

[0021] The monocoque bogie frame comprises at least two secondary suspension interfaces each for accommodating a vertical spring of a secondary suspension, the secondary suspension interfaces being located at each symmetric position on a respective side of the longitudinal midplane, each secondary suspension interface being closer to the transverse midplane than the support beam and the further support beam,

[0022] The monocoque bogie frame comprises at least two primary suspension interfaces each for accommodating a spring of a primary suspension, the primary suspension interfaces being located at each symmetric position on a respective side of the longitudinal midplane, each primary suspension interface being closer to the support beam than to the transverse midplane,

[0023] The monocoque bogie frame comprises at least two further primary suspension interfaces each for accommodating a spring of a further primary suspension, the further primary suspension interfaces being located at each symmetric position on a respective side of the longitudinal midplane, each further primary suspension interface being closer to the further support beam than to the transverse midplane.

[0024] In one embodiment, the monocoque bogie frame further comprises at least one intermediate crossbeam extending from one of the two side beams to the other, wherein the intermediate crossbeam is located between the support beam and the further support beam, closer to the lateral midplane than the support beam and the further support beam, and each cross section of the intermediate crossbeam, by a cross section plane parallel to the longitudinal midplane, has a planar moment of inertia and a polar moment of inertia which are at least twice, preferably 2.5 times, the planar moment of inertia M and the polar moment of inertia J of any cross section of the elongated portion of the support beam. In one embodiment, the monocoque bogie frame comprises a further intermediate crossbeam extending from one of the two side beams to the other, wherein the further intermediate crossbeam is located between the support beam and the further support beam, the intermediate crossbeam and the further intermediate crossbeam being located on either side of the lateral midplane of the monocoque bogie frame, closer to the lateral midplane than the support beam and the further support beam, and each cross section of the further intermediate crossbeam, by a cross section plane parallel to the longitudinal midplane, has a planar moment of inertia and a polar moment of inertia which are at least twice, preferably 2.5 times, the planar moment of inertia M and the polar moment of inertia J of any cross section of the elongated portion of the support beam. Since they are located closer to the center of the bogie, the intermediate crossbeam(s) do not need to be able to deform as much as the support beams.

[0025] Preferably, the bogie frame is provided with one or more of the following features:

[0026] The monocoque bogie frame is made in one piece;

[0027] The monocoque bogie frame is made of a single metallic material;

[0028] The monocoque bogie frame is made of steel;

[0029] The monocoque bogie frame is made of cast iron, preferably ductile cast iron.

[0030] According to another aspect of the application, there is provided a bogie for a rail vehicle, the bogie comprising at least one set of wheels; a monocoque bogie frame as disclosed herein supporting the at least one set of wheels; and a drive unit attached to the support portion of the support beam of the monocoque bogie frame. The drive unit can comprise a motor and / or a gearbox.

[0031] In one embodiment, the bogie further comprises wheel bearings for guiding the rotational movement of each wheel of the set of wheels about an axis of rotation, wherein the wheel bearings are located between the wheels of the set of wheels.

[0032] Preferably, the drive unit is further attached to the intermediate crossbeam at two locations of the intermediate crossbeam, wherein the two locations of the intermediate crossbeam are located on either side of the longitudinal midplane of the monocoque bogie frame. BRIEF DESCRIPTION OF DRAWINGS

[0033] Other advantages and features of the present application will become more apparent from the following description of a specific embodiment thereof, given by way of non-limiting example only, and presented in conjunction with the accompanying drawings, wherein:

[0034] Figure 1 is an isometric side view of a bogie according to an embodiment of the present application;

[0035] Figure 2 is a top view of the bogie of Figure 1

[0036] Figure 3 is a front view of the bogie of Figure 1

[0037] Figure 4 is a cross-sectional view of the support beam of Figure 1 along section line B-B of Figure 2

[0038] Figure 5 is a top view of the frame of the bogie of Figure 1

[0039] Figure 6 is an isometric side view of a support beam of the bogie frame of Figure 5

[0040] Figure 7 is a cross-sectional view of the support beam of Figure 6 along line C-C of Figure 5

[0041] Figure 8 is a cross-sectional view of the support beam of Figure 6 along line D-D of Figure 5

[0042] Figure 9 is a cross-sectional view of the support beam of Figure 6 along line E-E of Figure 5

[0043] Figure 10 is a cross-sectional view of the support beam of Figure 6 along line F-F of Figure 5

[0044] Figure 11 shows a plot of two functions of the associated cross-section of the support beam of Figure 6 along Figure 5 ​​​​​​​​​The distance measured in the transverse direction of the bogie frame is associated with the planar and polar moments of inertia.

[0045] Like reference numerals refer to like or identical components in each of the figures. DETAILED DESCRIPTION

[0046] REFERENCE Figures 1 to 4 The bogie 10 for a rail vehicle comprises two wheelsets (left and right wheelsets) 12, a unitary bogie frame 14 supported on the two wheelsets 12, and two drive units 16 attached to the bogie frame 14, each drive unit 16 being configured to drive one of the wheelsets.

[0047] Each wheelset 12 comprises two wheels 12.1 mounted on a common wheel axle 12.2. Two parallel wheel bearings 18 are located between the wheels 12.1 for guiding the rotational movement of each wheel 12.1 about an axis of rotation 100 of the wheel axle 12.2. The bogie frame 14 comprises a primary suspension interface 20 for mounting a primary suspension element (not shown) between the wheel bearings 18 and the bogie frame 14. The bogie frame further comprises two secondary suspension seats 22, each secondary suspension seat 22 being configured to accommodate a vertical spring (not shown) of a secondary suspension seat, the secondary suspension seats 22 being located at symmetrical positions on the sides of a longitudinal mid-plane 100 of the bogie frame 14, each secondary suspension seat 22 being closer to a transverse mid-plane 200 of the bogie frame 14 than the primary suspension interface 20, and preferably being centered with respect to the transverse mid-plane 200.

[0048] The bogie frame 14, which is shown in detail in Figures 5 to 10 The bogie frame 14, which is shown in detail in

[0049] The bogie frame 14 comprises two side beams 24, which are located on the left and right of the longitudinal midplane 100, respectively, extend in the longitudinal direction of the bogie frame 14, i.e. perpendicular to the transverse midplane 200, and are spaced apart from each other in the transverse direction of the bogie frame 14, i.e. perpendicular to the longitudinal midplane 100. The end portions of the side beams 24 extend above the wheel bearings 18 to form the primary suspension interfaces 20. The bogie frame further comprises two intermediate crossbeams 26 and two support beams 28 for connecting the two side beams 24 to each other. The intermediate crossbeams 26 extend from one of the two side beams 24 to the other and are located between the two support beams 28, the intermediate crossbeams 26 being closer to the transverse midplane 200 than to the support beams 28. The intermediate crossbeams 26 have a substantially constant cross section. The secondary suspension seats 22 are located on the side beams 24 between the intermediate crossbeams 26. The support beams 28 extend in the transverse direction of the bogie frame 14 to connect the two side beams 24 to each other at locations close to the primary suspension interfaces 20 and close to the end portions of the side beams 28.

[0050] Each support beam 28 comprises a support portion 30, an elongated portion 32 and a transition portion 34 between the support portion 30 and the elongated portion 32. Each support portion 30 of the two support beams 28 is directly connected to a different one of the two side beams 24 and indirectly connected to the opposite side beam 24 via the transition portion 34 and the elongated portion 32. The length of each support portion 30 extending in the transverse direction is less than two-fifths, and preferably less than one-third, of the total length L of the support beam 28 measured in the transverse direction from one of the side beams 24 to the other. The length of each elongated portion 32 extending in the transverse direction of the bogie frame is at least one-third, and preferably at least two-fifths, of the total length L of the support beam 28 measured in the transverse direction from one of the side beams to the other. The cross section of the elongated portion 28 is preferably I-shaped, as shown in Figure 9 and Figure 10 The elongated portion 32 is integrated into the end portion of the side beam 24 to avoid local stress concentrations.

[0051] Each support portion 30 is provided with an accessory interface 36, which can comprise one or more through holes for attaching a center pin of a rubber bushing 40 that is mounted in a through hole of a bracket 42 of a housing 44 of the drive unit 16. The housing 44 of each drive unit 16 is further attached to the associated one of the intermediate crossbeams 26 by anti-vibration mounts 46 at two locations 48 of the intermediate crossbeam 24, the anti-vibration mounts 46 being spaced apart from each other in the transverse direction and located on both sides of the longitudinal midplane 100 of the bogie frame 14. The rubber bushing 40 and the anti-vibration mounts 46 provide a three-point suspension between the housing 44 of each drive unit 16 and the bogie frame 14 to minimize the transmission of high-frequency vibrations and to allow a limited freedom of relative movement in all directions.

[0052] The support portions 30 of the two support beams 28 are located on opposite sides of a longitudinal mid-plane 100 of the bogie frame 14. The two support beams 28 are preferably symmetrical to each other with respect to a vertical intersection axis 300 between the longitudinal mid-plane 100 and a transverse mid-plane 200 of the bogie frame 14.

[0053] Each cross-section of the support beam 28, in particular the cross-sections C-C to F-F of Figures 7 to 10 have a planar moment of inertia M and a polar moment of inertia J. Figure 11 The two graphs of

[0054] As can be seen in the graphs, the planar moment of inertia M in the support portions 30 is at least twice the planar moment of inertia M in the slender portions 32, while the polar moment of inertia J in the support portions 30 is at least twice, preferably at least 2.5 times, the polar moment of inertia J in the slender portions 32.

[0055] The planar moment of inertia M and the polar moment of inertia J are continuously differentiable functions which preferably continuously decrease from the support portions 30 towards the slender portions 32 in the transition portions 34.

[0056] The bogie frame is designed as a torsionally flexible structure to accommodate large deformations at the primary suspension on a twisted track. The stiffer support portions 30 of the support beams 28 allow for a rigid support of the drive units 16, while the thinner slender portions 32 provide a reduced stiffness of the bogie frame 14. This design of the inhomogeneous support beams enables the slender portions 32 to locally deform, which allows the frame to more freely displace when supporting the drive units load.

[0057] The invention is equally applicable to bogies with independent wheels, i.e. with groups of wheels not connected to a common axle.

[0058] The two intermediate cross beams 28 can be replaced by a single cross beam or be completely omitted.

Claims

1. A bogie (10) for a rail vehicle, the bogie (10) comprising at least one wheelset (12), a monolithic bogie frame (14) supported on the at least one wheelset (12), and a drive unit (16) attached to the monolithic bogie frame (14) for driving the at least one wheelset (12), wherein the monolithic bogie frame (14) comprises: at least two side beams (24) extending in a longitudinal direction of the bogie frame (14) and spaced apart from each other in a transverse direction of the bogie frame (14), respectively on a left side and a right side of a longitudinal midplane (100) of the bogie frame (14); and at least one support beam (28) extending in the transverse direction of the bogie frame (14), wherein the support beam (28) is rigidly connected to each of the two side beams (24) and the support beam (28) comprises a support portion (30) for supporting the drive unit (16) of the bogie (10) and an elongated portion (32), wherein each cross section of the support beam (28) by a transverse plane parallel to the longitudinal midplane (100) has a planar moment of inertia (M) and a polar moment of inertia (J), characterized in that the support portion (30) is directly connected to one of the two side beams (14) and connected to the other one of the two side beams (14) by the elongated portion (32), wherein the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the support portion (30) of the support beam (28) are at least twice the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the elongated portion (32) of the support beam (28), respectively.

2. The bogie (10) according to claim 1, wherein the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the support portion (30) of the support beam (28) are at least 2.5 times the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the elongated portion (32) of the support beam (28), respectively. The length of the elongated portion (32) extending in the transverse direction is at least one third of the total length of the support beam (28) measured in the transverse direction from one of the side beams (24) to the other one.

3. The bogie (10) according to claim 1, characterized in that 4. The bogie (10) according to claim 1, wherein the length of the elongated portion (32) extending in the transverse direction is at least two fifths of the total length of the support beam (28) measured in the transverse direction from one of the side beams (24) to the other one. The length of the support portion (30) extending in the transverse direction is less than two fifths of the total length of the support beam (28) measured in the transverse direction from one of the side beams (24) to the other one.

5. The bogie (10) according to claim 1 or 3, characterized in that ​ 6. The bogie (10) according to claim 1 or 2 or 4, wherein the length of the support portion (30) extending in the transverse direction is less than one third of the total length of the support beam (28) measured in the transverse direction from one of the side beams (24) to the other.

7. The bogie (10) according to claim 1 or 3, characterized in that The support beam (28) further comprises a transition portion (34) extending from the support portion (30) to the elongated portion (32), wherein the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the transition portion (34) decrease as the distance of the cross section to the support portion (30) increases.

8. The bogie (10) according to claim 1 or 3, characterized in that The polar moment of inertia (J) of any cross section of the support portion (30) of the support beam (28) is at least three times the polar moment of inertia (J) of any cross section of the elongated portion (32) of the support beam (28).

9. The bogie (10) according to claim 1 or 3, wherein the monocoque bogie frame (14) comprises a further support beam (28) extending in the transverse direction of the monocoque bogie frame (14), wherein the support beam (28) and the further support beam (28) are spaced apart from each other in the longitudinal direction of the monocoque bogie frame (14) on a front side and a rear side of a transverse midplane (200) of the monocoque bogie frame (14), respectively, wherein the further support beam (28) comprises a further support portion (30) for supporting a drive unit (16) or a further drive unit (16) of the bogie (10), the further support portion (30) being connected to one of the two side beams (24) and directly connected to the other one of the two side beams (24) by a further elongated portion (32), wherein each cross section of the further support beam (28) being transversely cut by a cross section plane parallel to the longitudinal midplane (100) has a planar moment of inertia (M) and a polar moment of inertia (J), and the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the further support portion (30) of the further support beam (28) are at least twice the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the further elongated portion (32) of the further support beam (28), respectively.

10. The bogie (10) according to claim 9, characterized in that One or more of the following conditions are met: The support portion (30) and the further support portion (30) are located on opposite sides of the longitudinal midplane (100) of the monocoque bogie frame (14), and / or The support beam (28) and the further support beam (28) are symmetrical or substantially symmetrical with respect to a vertical intersection axis (300) between the longitudinal midplane (100) and the transverse midplane (200) of the monocoque bogie frame (14), and / or The support beam (28) is closer to an end of the monocoque bogie frame (14) than to the transverse midplane (200), and / or The further support beam is closer to a further end of the monocoque bogie frame (14) than to the transverse midplane (200), and / or The monocoque bogie frame (14) comprises at least two secondary suspension interfaces (22) each for accommodating a vertical spring of a secondary suspension, said secondary suspension interfaces (22) being located at each symmetrical position on a respective side of the longitudinal midplane (100), each secondary suspension interface (22) being closer to the lateral midplane (200) than to the support beam (28) and the further support beam (28), and / or The monocoque bogie frame (14) comprises at least two primary suspension interfaces (20) each for accommodating a spring of a primary suspension, said primary suspension interfaces (20) being located at each symmetrical position on a respective side of the longitudinal midplane (100), each primary suspension interface (20) being closer to the support beam (28) than to the lateral midplane (200), and / or The monocoque bogie frame (14) comprises at least two further primary suspension interfaces (20) each for accommodating a spring of a further primary suspension, said further primary suspension interfaces (20) being located at each symmetrical position on a respective side of the longitudinal midplane (100), each further primary suspension interface (20) being closer to the further support beam (28) than to the lateral midplane (200).

11. The bogie (10) according to claim 9, wherein the monocoque bogie frame (14) further comprises at least one intermediate crossbeam (26) extending from one of the two side beams (24) to the other, wherein the intermediate crossbeam (26) is located between the support beam (28) and the further support beam (28), closer to the lateral midplane (200) than to the support beam (28) and the further support beam (28), and each cross section of the intermediate crossbeam (26) transversely intersected by a cross section plane parallel to the longitudinal midplane (100) has a planar moment of inertia and a polar moment of inertia at least twice as large as the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the elongated portion (32) of the support beam (28).

12. The bogie (10) according to claim 11, wherein the monocoque bogie frame (14) comprises a further intermediate crossbeam (26) extending from one of the two side beams (24) to the other, wherein the further intermediate crossbeam (26) is located between the support beam (28) and the further support beam (28), the intermediate crossbeam (26) and the further intermediate crossbeam (26) being located on both sides of the lateral midplane (200) of the monocoque bogie frame (14), closer to the lateral midplane than to the support beam (28) and the further support beam (28), and each cross section of the further intermediate crossbeam (26) transversely intersected by a cross section plane parallel to the longitudinal midplane has a planar moment of inertia and a polar moment of inertia at least twice as large as the planar moment of inertia (M) and the polar moment of inertia (J) of any cross section of the elongated portion (32) of the support beam (28).

13. Bogie (10) according to claim 1 or 3, provided with one or more of the following features: - the monolithic bogie frame (14) is integrally produced; - the monolithic bogie frame (14) is produced from a single metallic material; - the monolithic bogie frame (14) is produced from steel; - the monolithic bogie frame (14) is produced from cast iron.

14. Bogie (10) according to claim 13, wherein the cast iron from which the monolithic bogie frame (14) is produced is nodular cast iron.

15. Bogie (10) according to claim 1, further comprising a wheel bearing (18) for guiding a rotational movement of each wheel (12.1) of the wheel set (12) about an axis of rotation, wherein the wheel bearing (18) is located between the wheels (12.1) of the wheel set (12).

16. Bogie (10) according to claim 8, wherein the drive unit (16) is further attached to the intermediate crossbeam (26) at two locations (48) of the intermediate crossbeam (26), wherein the two locations (48) of the intermediate crossbeam (28) are located on both sides of a longitudinal midplane (100) of the monolithic bogie frame (14).

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