Axle bearing arrangement for a rail vehicle

Abstract

Disclosed is an axle bearing arrangement for a rail vehicle, comprising at least one housing (1) and at least one cover (2, 4), wherein the housing (1) has a casing (8) which encloses a bore (6) extending along a central axis and is designed to receive a bearing unit, has a side surface (10) surrounding the bore (6) and at least one housing fastening bore (12), wherein the at least one cover (2, 4) has a flange (18) with a flange side surface (19, 20) facing the side surface (10) of the housing (1) and comprises at least one cover fastening bore (22), wherein the housing fastening bore (12) and the cover fastening bore (22) are designed to receive at least one fastening element for fastening the cover (2, 4) to the housing (1), wherein a part of the side surface (10) of the housing (1) and / or a part of the side surface (19,20) of the flange (18) is designed to project from the respective side surface (10, 19, 20) and defines a contact surface (24) in which the side surface (10) of the housing (1) and the side surface (19, 20) of the flange (18) are in contact with each other.,

Description

Technical field of the invention

[0001] The present invention relates to an axle bearing arrangement for a rail vehicle. Background of the invention

[0002] As is well known, axle boxes are attached to rail vehicles such as trains, in particular locomotives, passenger coaches, and freight wagons. Generally, a rail vehicle comprises several bogies. Each bogie comprises a frame, two (or more) wheelsets, and four (or more) axle boxes. Each wheelset comprises an axle carrying two wheels. The axle box is the connecting element between the rotating wheelset and the quasi-static frame of the bogie. The axle box comprises mounts for a housing with offset coil springs and a housing that houses a bearing unit.

[0003] The bearing unit is generally mounted within the housing between a rear cover and a front cover, with an axle passing through the rear cover and supported for rotation by the bearing unit. Typically, both the rear and front covers are rigidly connected to the housing by four bolts or screws attached to the housing. The front and rear covers rest against the housing along a contact surface, usually annular, so that the entire surfaces of the housing and the respective cover are in contact with each other.

[0004] However, uneven tightening of bolts or screws can lead to uneven contact pressure, which can cause vibrations that can lead to reduced reliability of the screw connection.

[0005] It is therefore an object of the present invention to provide an axle bearing arrangement which has improved reliability of the screw connection. Summary of the invention

[0006] This object is achieved by a bearing arrangement according to claim 1.

[0007] The following provides a bearing assembly for a rail vehicle. The axle bearing assembly comprises at least one housing and at least one cover, wherein the housing has a shell that encloses a bore extending along a central axis and is configured to receive a bearing unit. The housing further comprises a side surface surrounding the bore and at least one housing fastening bore. The housing can be made of metal such as cast iron, steel, and / or a light metal alloy. Alternatively, the housing can also be made of plastic, in particular fiber-reinforced plastic. Furthermore, the housing can be manufactured by a molding process, a casting process, a machining process, an additive manufacturing process, and the like.

[0008] Furthermore, the at least one cover has a flange having a flange side surface facing the side surface of the housing and comprising at least one cover fastening bore, wherein the housing fastening bore and the cover fastening bore are designed to receive at least one fastening element for fastening the cover to the housing. The at least one cover can be made of metal such as cast iron, steel and / or a light metal alloy. Alternatively, the at least one cover can also be made of plastic, in particular of fiber-reinforced plastic. Furthermore, the at least one cover can be produced by a molding process, a casting process, a machining process, an additive manufacturing process and the like.

[0009] Preferably, the at least one fastening element is a screw and / or a bolt and a nut. A washer may also be provided. Bolts can have the particular advantage of having a reduced axial spacing in the area of ​​a wheel. Furthermore, the housing fastening hole can be a threaded hole. Alternatively, the housing fastening hole can also be a through hole.

[0010] Preferably, the bore in the housing is a through-bore. If the housing bore is a through-bore, the bearing assembly of the axle bearing assembly may comprise a front cover configured such that a cover mounting hole of the front cover is aligned with a first opening of the through-bore, and a rear cover configured such that a cover mounting hole of the rear cover is aligned with a second opening of the through-bore, wherein the second opening of the through-bore is arranged opposite the first opening of the through-bore.

[0011] To improve the reliability of the attachment of the at least one cover to the housing, a portion of the side surface of the housing and / or a portion of the side surface of the flange is configured to project from the respective side surface and define a contact surface in which the side surface of the housing and the side surface of the flange are in contact with each other. Preferably, the side surface of the housing and / or the side surface of the flange comprises a plurality of contact surfaces. The plurality of contact surfaces can, for example, be evenly distributed in the circumferential direction around the bore of the housing.

[0012] By providing a contact surface that protrudes from the respective side surface, it is possible to create a well-defined contact surface between the side surface of the housing and the side surface of the at least one cover. In other words, the side surface of the housing and the side surface of the at least one cover only touch at the contact surface. This allows for a more symmetrical pressure cone under the fastening element than in the case where the entire side surface of the housing and the at least one cover are in contact with each other, resulting in increased mechanical strength of the fastening element and a more homogeneous contact pressure under the fastening element. The reliability of the screw connection is increased.

[0013] In addition, the more symmetrical pressure cone under the fastener can reduce or even eliminate vibrations on the respective parts, namely the housing, the cover and / or the fastener, resulting in increased reliability of the screw connection.

[0014] Preferably, the at least one contact surface is provided near the housing mounting hole and / or the flange mounting hole. For example, the at least one contact surface can be provided around the housing mounting hole and / or the flange mounting hole. The contact surface can, for example, have an annular shape. Preferably, the contact surface has at least the size of the screw head and / or the size of the nut and / or the size of a washer. The size of the screw head and / or the size of the nut and / or the size of a washer can be defined by a diameter thereof. This has the advantage that the costs for machining the contact surfaces can be reduced because the area that must be machined to the required tolerance is reduced and / or limited to the contact surfaces.In addition, since only a small part of the side surface of the housing and / or part of the side surface of the flange are in contact with each other, the quality of the geometric tolerances can be increased.

[0015] Furthermore, a gap may be formed between the side surface of the housing and the side surface of the flange outside the contact area in an assembled state. The gap may, for example, be a few millimeters wide, preferably between 1 mm and 10 mm. This has the advantage of reducing corrosion between the contacting parts because the non-contacting surface can be protected with paint. Additionally, a washer may be provided around the housing mounting hole and / or the flange mounting hole between the side flange of the housing and the side flange of the at least one cover.

[0016] Further preferred embodiments are defined in the dependent claims as well as in the description and the figures. Elements described or shown in combination with other elements may be present alone or in combination with other elements without departing from the scope of protection. Brief description of the drawings

[0017] Preferred embodiments of the invention are described below with reference to the drawings, which are merely exemplary and not intended to limit the scope of protection. The scope of protection is defined exclusively by the appended claims.

[0018] The figures show: Fig. 1: a housing for an axle bearing arrangement according to a first embodiment, Fig. 2: a front cover for the axle bearing assembly according to the first embodiment, Fig. 3: a rear cover for the axle bearing assembly according to the first embodiment, Fig. 4: a housing for an axle bearing arrangement according to a second embodiment, Fig. 5: a front cover for the axle bearing assembly according to the second embodiment, Fig. 6: a rear cover for the axle bearing assembly according to the second embodiment, and Fig. 7: a housing for an axle bearing arrangement according to a third embodiment. Detailed description of the invention

[0019] In the following, identical or similar functional elements are designated by the same reference numbers.

[0020] The Fig. Figures 1 to 3 show the parts of an axle box assembly, namely a housing 1, a front cover 2, and a rear cover 4 according to a first embodiment. An axle box is particularly important for rail vehicles, such as locomotives, passenger coaches, and freight cars.

[0021] In this and the following embodiments, the terms "front" and "rear" are also defined with respect to the position of the axle box relative to the railway bogie, with a front portion positioned at an axial end of the axle box towards the outside of the railway bogie and a rear portion positioned at an axial end of the axle box towards the inside of the railway bogie corresponding to the side of the wheel.

[0022] The housing 1 is in Fig. 1 and comprises a shell 8 which includes a through bore 6 extending along a central axis and defining an axial passage for an axle (not shown). A bearing unit (not shown) is fixed in the central bore 6 of the housing 1. The bearing unit is of a general type, for example the bearing unit can be a cylindrical roller bearing unit or a tapered roller bearing unit having a stationary outer ring housed in the bore 6 of the housing 1, a rotating inner ring press-fitted onto an outer cylindrical surface of one axial end of the axle, and rollers arranged radially between the outer and inner rings.

[0023] The housing 1 further comprises a side surface 10 surrounding the bore 6 on the front side and four radially projecting sections 14, each of the radially projecting sections 14 comprising a housing fastening bore 12. The housing fastening bores 12 are arranged near the bore 6 of the housing 1. As can be seen from Fig. 1, the housing fastening holes 12 are equally spaced circumferentially.

[0024] In Fig. 1, the housing 1 is shown from a front side, so that the front side surface 10 is visible. In the embodiments shown, a rear side surface 11 ( Fig. 4) an identical number of radially projecting portions 14 and housing mounting holes 12 located at the same circumferential positions. Alternatively, more or fewer projecting portions 14 and / or housing mounting holes 12 may be provided at different circumferential positions on the rear surface of the housing, and the projections may be unevenly distributed circumferentially on the rear surface.

[0025] The front cover 2 is in Fig. 2 and the rear cover 4 is in Fig. 3. The front cover 2 and the rear cover 4 each comprise an inner bore 15, 16 defining an axial passage for an axle (not shown) intended to be rotatably supported by the bearing unit. Both the front cover 2 and the rear cover 4 comprise a flange 18 with a flange side surface 19, 20 facing the respective side surface 10 of the housing 1 and comprising four cover fastening bores 22, wherein the housing fastening bores 12 and the cover fastening bores 22 are configured to receive at least one fastening element (not shown) for fastening the covers 2, 4 to the housing 1.

[0026] Preferably, the at least one fastening element is a screw and / or a bolt and a nut. A washer may also be provided. For example, the screw and / or the bolt may be secured by a threaded hole and / or a washer and a nut. Furthermore, the housing mounting hole 12 may be a threaded hole. Alternatively, the housing mounting hole 12 may also be a through hole.

[0027] As in the Fig. 2 and Fig. 3, a part of the side surface 19, 20 of the flange 18 of the covers 2, 4 is designed such that it projects from the respective side surface 19, 20 and defines a contact surface 24 in which, when the covers 2, 4 are mounted on the housing 1, the side surface 10 of the housing 1 and the side surfaces 19, 20 of the flange 18 are in contact with each other.

[0028] In the first embodiment, the contact surfaces 24 are provided around the flange mounting hole 22 and have an annular shape. However, the contact surface may have any suitable shape. Preferably, the contact surface 24 is at least the size of the bolt head and / or the nut and / or a washer. Preferably, each flange mounting hole 22 is provided with a contact surface 22.

[0029] In the assembled state, the projecting contact surface 24 forms a gap (not shown) between the side surface 10 of the housing 1 and the side surface 19, 20 of the covers 2, 4 outside the contact surface 24. The gap can be, for example, a few millimeters wide, preferably between 1 mm and 10 mm. This has the advantage of reducing corrosion between the contacting parts, since the non-contacting surface can be protected with paint.

[0030] The Fig. 4 to 6 show the parts of an axle bearing assembly, namely a housing 1, a front cover 2, and a rear cover 4 according to a second embodiment. The axle bearing assembly according to the second embodiment differs from the first embodiment in that the contact surfaces 24 are provided around the housing mounting holes 12 on the housing 1, as shown in Fig. 4 can be seen.

[0031] Fig. Figure 7 shows a housing 1 for an axle bearing assembly according to a third embodiment. The bearing assembly according to the third embodiment differs from the second embodiment in that, in addition to the contact surface 24, a washer 26 is provided around the housing mounting holes 12 between the side surface 10 of the housing and the side flange 19, 20 of the covers 2, 4.

[0032] According to embodiments not shown, the axle bearing may further comprise known additional parts, such as sealing means, an end cap screwed onto an axial axle end, a support ring inserted axially between a step of the axle and the bearing unit, and the like.

[0033] In summary, by providing a contact surface 24 that protrudes from the respective side surface 10, 19, 20, a well-defined contact surface can be created between the side surface 10 of the housing 1 and the side surfaces 19, 20 of the covers 2, 4. In other words, the side surfaces 10 of the housings and the side surfaces 19, 20 of the covers 2, 4 only touch at the contact surfaces 24. This allows a more symmetrical pressure cone to be achieved under the fastener than in the case where the entire side surface 10 of the housing 1 and the entire side surface 19, 20 of the covers 2, 4 are in contact with each other, resulting in increased mechanical strength of the fastener. Furthermore, the reliability of the screw assembly can be increased.

[0034] Furthermore, the more symmetrical pressure cone under the fastener allows vibrations on the respective parts, namely the housing 1, the covers 2, 4, and / or the fastener, to be reduced or even eliminated, resulting in increased reliability of the screw connection. Furthermore, since only a small portion of the side surface 10 of the housing 1 and / or a portion of the side surface 19, 20 of the covers 2, 4 are in contact with each other, the quality of the geometric tolerances can be increased and / or the costs for machining the contact surfaces can be reduced, since the area that must be machined to the required tolerance is reduced and / or limited to the contact surfaces 24. List of reference symbols 1 housing 2 front cover 4 rear cover 6 Hole 8 coat 10 front side surface 11 rear side surface 12 Housing mounting hole 14 radially projecting section 15 Inner hole of the front cover 16 Inner hole of the rear cover 18 Flange 19 Flange side surface of the front cover 20 Flange side surface of the front cover 22 Cover mounting hole 24 contact surface 26 Washer

Claims

[1] An axle bearing arrangement for a rail vehicle, comprising at least one housing (1) and at least one cover (2, 4), wherein the housing (1) has a casing (8) which encloses a bore (6) extending along a central axis and is designed to receive a bearing unit, a side surface (10) which surrounds the bore (6), and at least one housing fastening bore (12), wherein the at least one cover (2, 4) has a flange (18) with a flange side surface (19, 20) facing the side surface (10) of the housing (1) and comprises at least one cover fastening bore (22), wherein the housing fastening bore (12) and the cover fastening bore (22) are designed to receive at least one fastening element for fastening the cover (2, 4) to the housing (1), characterized bythat a part of the side surface (10) of the housing (1) and / or a part of the side surface (19, 20) of the flange (18) is designed to project from the respective side surface (10, 19, 20) and defines a contact surface (24) in which the side surface (10) of the housing (1) and the side surface (19, 20) of the flange (18) are in contact with one another. [2] Axle bearing assembly according to claim 1, wherein the at least one contact surface (24) is provided in the vicinity of the housing mounting bore (12) and / or the flange mounting bore (22). [3] Axle bearing arrangement according to claim 1 or 2, wherein in the assembled state a gap is formed between the side surface (10) of the housing (1) and the side surface (19, 20) of the flange (18) outside the contact surface (24). [4] Axle bearing assembly according to one of the preceding claims, wherein the at least one contact surface (24) has an annular shape. [5] Axle bearing assembly according to one of the preceding claims, wherein the housing mounting bore (12) is a threaded bore. [6] Axle bearing assembly according to one of claims 1 to 4, wherein the housing mounting bore (12) is a through bore. [7] Axle bearing assembly according to one of the preceding claims, wherein the contact surface (24) has at least the size of a head of the fastening element. [8] Axle bearing arrangement according to one of the preceding claims, wherein the side surface (10) of the housing and / or the side surface (19, 20) of the flange (18) comprises a plurality of contact surfaces (24). [9] Axle bearing assembly according to claim 8, wherein the plurality of contact surfaces (24) are evenly distributed in a circumferential direction of the bore (6). [10] Axle bearing assembly according to one of the preceding claims, wherein a washer (24) is provided around the housing mounting hole (12) and / or the flange mounting hole (22) between the side flange of the housing and the side flange of the at least one cover.

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