FR2717122A1 - Wheels for rail vehicles - Google Patents

Abstract

The wheels of vehicles, which are designed to run on iron tracks, are arranged on an axle (2) and consist of a hub (5), a flange section or a set of spokes (4), an outer rim (15) and a rolling surface (3). The flange section of the wheel is covered by stream-lining in order to reduce the running noise from the wheel. The stream-lining takes the form of a covering piece (7,8), which extends cover from the hub of the wheel to the rim, and which is fixed on both sides of the flange section, in such a way as to enclose it. The cover carries absorbent material to reduce the noise levels and is fitted in such a way as to be decoupled from the flange section of the wheel.

Description

 The present invention relates to the wheels of vehicles which are able to move relative to the ground on railways, for example wagons, cars and locomotives.

 Railway vehicles have either single axles or axles grouped into bogies.

 The wheels (1) of each axle (2) comprise a tread table (3), a tire (15), a web or sticks (4) and a hub (5) fixed to the axle shaft (2 ).

 When the wheel moves on the rail (6), especially at high speed, the tread (3) is subjected to excitations, coming either from the shape of the rail, or from its own shape (micro defect in shape) .

 These excitations generate vibrations throughout the structure of the wheel, and in particular, in the web (or the wheel sticks (4)), which play the role of "loudspeaker". The veil thus transforms the solidary vibrations of the metal into aerial acoustic vibrations. These are emitted perpendicular to the surface of the veil and create a very high noise level in the vicinity of the tracks. This causes inconvenience for residents, gives a very bad image to the railway, and is one of the main causes of nuisance for this type of means of transport.

 Having become aware of this problem, those responsible for railway equipment are considering the use of body-mounted fairings intended to partially mask and absorb the noise emitted by the wheels.

 We believe that these fairings are located too far from the source and therefore mask the latter very imperfectly.

 The invention consists in placing fairings directly at the source, so as to kill the noise with the minimum fairing surface and the maximum efficiency. Figures 1 and 2 show a configuration given by way of illustration but in no way limiting.

 The fairing preferably consists of 2 parts, (7 and 8), located on either side of the wheel disc.

Preferably, these fairings cover in a "sealed" manner the space going from the tire (15) to the hub (5).

Preferably, these fairings (lids) can be formed
- By an outer skin (9), thick (mass effect), this skin can be made of any material such as a metal (ex steel), or better a composite such preferably carbon or glass, for example with organic or metallic matrix.

 - By an absorbent medium (10) which can preferably be a honeycomb or any other equivalent medium, foam, glass or rock wool, viscoelastic material, etc.

This medium (10) can have several absorption stages as shown in FIG. 2 where it is preferable to see that the medium (10) has been broken down into two absorbent layers (19 and 17), separated by a membrane (16 ) with an inertia effect which can be metallic or composite and serves as an acoustic barrier.

 - The layer (11) completes the structure of the fairing, it can use the same materials as the skin (9), but preferably is perforated. The surface of the layer (11) can be either smooth or better, have a relief (pyramid, cone, etc.), so as to widen the absorption spectrum.

 - Finally, the cavity (12) can be empty or better, filled with an absorbent medium such as foam or any other equivalent material (rock wool or glass etc).

 NOTE O: One or more of the constituents previously described can be omitted or repeated several times without departing from the scope of the field claimed by the invention.

 The bearing faces of the fairing (7 or 8) with the hub (5) and the tire (15) are preferably decoupled from the metal of the wheel by a layer respectively (13 and 14) of materials, isolating vibrations. This layer, for example, can be of viscoelastic material (such as rubber), fibrous, cellular or be a thin layer of air.

 NOTE 1: The surface of the web (4) can carry an acoustic treatment layer, preferably adhered rubber.

An alternative consisting in adhering a viscoelastic material, tar or preferably rubber on (all) the surface of the veil and optionally covering it with a layer of any material preferably lead is within the scope of the invention.

 REMARK 2: Any means of maintaining the fairings on the wheel by bolting in particular at the level of the hub (5) in the zone (18), according to the rules, of the art is admissible.

 It is necessary to take precautions with the "passage of wall", of the screws and under the head of this one so that a visco-elastic material (or fibrous), isolates the veil (9) from the rising of solidary vibrations coming from the hub 5).

 In particular, a fixing means can be bonding (5) by rubber adhesion, on its 2 faces at (14) and (13), and possibly (20).

 Finally, one can imagine tie rods connecting the fairing (9) to the fairing (8) passing between the sticks of the veil (4) or in the middle of large holes made in it.

 REMARK 3: One can imagine that the fairings, thus described, are in several parts, to facilitate the installation and the removal and therefore the maintenance.

 The assembly of the parts is done according to the rules of art.

 REMARK 4: The combination of a perforated face (11), a honeycomb (15) and a material with inertia effect (16), constitutes an absorbent structure by its geometry in Elmnltz resonator .

Claims (9)

 1 - Wheel (1) of a railway vehicle mounted on an axle (2) comprising a hub (5), a web (4), a tire (15) and a tread table (3), characterized in that it further comprises at least one cover (7,8) located in line with the veil by enclosing it from the hub (5) to the tire (15) and means for decoupling said cover from said veil.  2 - Wheel according to claim 1, characterized in that said lids of said web are in several parts removable between them.  3 - Wheel according to claims 1 and 2, characterized in that the means for decoupling said cover from said web are constituted by a layer of a material with low solidary transmission interposed between said web and said cover.  4 - Wheel according to claims 1 and 3, characterized in that the cover carries an absorbent material (10 11-17-12-19-20), intended to dampen the sound vibrations emitted by the veil.  5 - Wheel according to one of claims 1 to 4, characterized in that said cover is made of a material with inertia effect (9,16).  6 - Wheel according to claims 1 to 5, characterized in that said decoupling layer consists of an air layer, a cellular material, fibrous or visco-elastic.  7 - Wheel according to claims I to 6, characterized in that said layer of an absorbent material (10,11,17,12,19,20) is interposed between the materials with inertia effect (9,16) and said veil.  8 - Wheel according to one of claims 1 to 7, characterized in that said absorbent material is chosen from the following materials: visco-elastic material, bituminous material, fibrous material, cellular material.  9 - Wheel according to one of claims 1 to 8, characterized in that said material with inertia effect consists of at least one of the following materials metallic material, composite material with metallic or organic matrices.