Railway vehicle brake disc

The railway vehicle brake disc includes a cylindrical hub, friction ring, and bell-shaped flange connecting the hub with the friction ring. The cylindrical hub defines a central axis and has an axial width and an outer diameter. The surface at the outer diameter defines an outer hub periphery. The friction ring includes two opposed annular members each having an outer braking surface and an inner surface. The annular members are connected to each other by a plurality of fins extending from the inner surface of one annular member to the inner surface of the other annular member. The bell-shaped flange has an inner portion connected to the hub, an outer portion connected to the fins, and a radial portion connecting the inner portion to the outer portion. The hub, friction ring, and bell-shaped flange are formed integrally from a single material.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a railway vehicle brake disc and, further, to a monoblock brake disc having a hub and friction ring connected by a flange.

2. Description of Related Art

Brake discs for trains are typically pressed onto the axle or bolted to the wheel. Axle-mounted brake discs can be made from a single casting or may include a separate hub and friction ring that are bolted together, such as found in U.S. Pat. No. 6,808,050 to Lehmann et al. One-piece or monoblock brake discs typically incorporate radial spokes connecting the hub to the friction ring, such as found in U.S. Pat. No. 4,638,891 to Wirth. Heat generated during braking causes the friction ring to expand radially outward. In the two-piece brake disc design, the friction ring is generally allowed to expand relative to the hub as the disc heats up due to braking. This expansion is accommodated by the disc-hub connection.

Referring toFIGS. 1 and 2, a conventional one-piece brake disc1includes a friction ring2secured to a hub3by a plurality of spaced spokes4. In this one-piece brake disc design, the spokes4that connect the friction ring to the hub3are stretched in tension as the friction ring heats up due to braking. The tension of the connecting spokes4during braking tends to pull the hub3away from the axle, which reduces the press fit of the hub3on the axle and can cause the disc to spin on the axle.

Referring toFIGS. 3 and 4, a further conventional design utilizes a brake disc6having a flange7to attach the friction ring8to the hub9. This brake disc6is a two-piece casting with different materials being used for the friction ring8than the connecting flange/hub7,9, which presents certain problems during manufacturing of the brake disc6.

United States Patent Application Publication Nos. 2004/0124045 and 2007/0181389 generally disclose brake discs having spokes connecting the hub to the friction ring and are hereby incorporated by reference in their entirety.

SUMMARY OF THE INVENTION

The railway vehicle brake disc described in detail herein comprises a cylindrical hub, a friction ring, and a bell-shaped flange connecting the hub with the friction ring. The cylindrical hub defines a central axis and has an axial width and an outer diameter. The surface at the outer diameter defines an outer hub periphery. The friction ring includes two opposed annular members each having an outer braking surface and an inner surface. The annular members are connected to each other by a plurality of fins extending from the inner surface of one annular member to the inner surface of the other annular member. The bell-shaped flange has an inner portion connected to the hub, an outer portion connected to the fins, and a radial portion connecting the inner portion to the outer portion. The hub, friction ring, and bell-shaped flange are formed integrally from a single material such that the brake disc is a monoblock brake disc.

The hub has a first axial end and a second axial end defining the axial width and the inner portion of the bell-shaped flange may be connected to the hub at the first axial end. The inner portion may also extend radially outward from the first axial end in a common plane with the first axial end. Additionally, the inner portion may extend axially past the first axial end. Further, the inner portion may be arcuate-shaped. Moreover, the inner portion may extend radially outward from the outer hub periphery.

The inner portion, outer portion, and radial portion of the bell-shaped flange may further be of generally uniform or generally non-uniform thickness. The radial portion may define an angle with the outer hub periphery or be generally parallel to the outer hub periphery.

In a further embodiment, the railway vehicle brake disc comprises a cylindrical hub, a friction ring, and a bell-shaped flange connecting the hub with the friction ring. The cylindrical hub defines a central axis and has an axial width and an outer diameter. The surface at the outer diameter defines an outer hub periphery. The friction ring includes two opposed annular members each having an outer braking surface and an inner surface. The annular members are connected to each other by a plurality of fins extending from the inner surface of one annular member to the inner surface of the other annular member. The bell-shaped flange has an inner portion connected to the hub, an outer portion connected to one of the two opposed annular members, and a radial portion connecting the inner portion to the outer portion.

In another embodiment, the railway vehicle brake disc comprises a cylindrical hub defining a central axis with the hub having an axial width and an outer diameter. The surface at the outer diameter defines an outer hub periphery. The disc further includes a friction ring comprising two opposed annular members each having an outer braking surface and an inner surface. The annular members are connected to each other by a plurality of fins extending from the inner surface of one annular member to the inner surface of the other annular member. A flange connects the hub with friction ring. The flange comprises an inner portion connected to the hub, an outer portion connected to the fins, and a radial portion connecting the inner portion to the outer portion. The hub comprises a first axial end and a second axial end defining the axial width, and the inner portion of the flange is connected to the hub at a position intermediate the first axial end and the second axial end. The radial portion may be generally C-shaped. The hub, friction ring, and flange may be formed integrally from a single material such that the brake disc comprises a monoblock brake disc.

Further details and advantages will become clear upon reading the following detailed description in conjunction with the accompanying drawings, wherein like parts are designated with like reference numerals and characters throughout.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, spatial orientation terms, as used, shall relate to the referenced embodiment as it is oriented in the accompanying drawing figures or otherwise described in the following detailed description. However, it is to be understood that the embodiments described hereinafter may assume many alternative variations and embodiments. It is also to be understood that the specific devices and components illustrated in the accompanying drawing figures and described herein are simply exemplary and should not be considered as limiting.

Referring toFIGS. 5-8, one embodiment of a brake disc20includes a friction ring22, a hub24, and a flange26. In the present embodiment, the friction ring22, hub24, and connecting flange26are integrally formed so that the brake disc20comprises a monoblock brake disc. The friction ring22includes two opposed annular members28,29each having an outer braking surface30and an inner surface32. The annular members28,29are connected to each other by a plurality of radially-spaced pin fins34extending from the inner surface32of one annular member28to the inner surface32of the other annular member29, although other suitable fin arrangements, such as radial fins, may be used. The hub24includes a cylindrically-shaped body36having a first axial end38and a second axial end40. The cylindrical-shaped body36comprises an outer surface forming an outer hub periphery or surface39. The cylindrical-shaped body36has an axial width W defined between the first axial end38and the second axial end40. The hub body36also defines a central opening42configured to receive an axle (not shown) and having a central axis L. The hub24may be press-fit onto the axle as is known in the railway vehicle field.

The flange26is generally bell-shaped and includes an inner portion44, an outer portion46, and a radial portion48and connects the friction ring22to the hub body36. In the embodiment ofFIGS. 5-8, the inner portion44of the flange26is connected to the hub body36of the hub24at the first axial end38of the hub body36and the flange26generally extends to a position approximately midway between the annular members28,29of the friction ring22. The outer portion46of the flange26is connected to a plurality of the pin fins34to secure the outer portion46of the flange26to the inner surfaces32of the annular members28,29. As shown more clearly inFIG. 7, the outer portion46of the flange26is connected by two rows of pin fins34on each side of the flange26, although the number of pin fins34connecting the flange26to the friction ring22may vary.

As noted, the flange26is generally bell-shaped and the radial portion48extends between the inner portion44and the outer portion46of the flange26. In particular, in the present embodiment, the inner portion44of the flange26connects to the first end38of the hub body36and the radial portion48extends radially outward at a slight taper or angle relative to the outer hub periphery or surface39and then transitions to the outer portion46. Thus, the radial portion48extends radially from the inner portion44and transitions to the outer portion46and the outer portion46transitions to a position laterally between the annular members28,29of the friction ring22in the present embodiment. The outer portion46of the flange26extends from the radial portion48for connection to the pin fins34. Thus, in the present embodiment, the inner portion44and the outer portion46of the flange26are generally straight or generally parallel with one another (as shown in cross-section) with the radial portion48extending between the inner and outer portions44,46at a slight taper or angle. The brake disc20may be manufactured from a single material, such as steel, as a one-piece casting, although other suitable materials may be used. As depicted inFIGS. 5-8, in the present embodiment, the inner portion44, outer portion46, and radial portion48generally have a uniform thickness relative to one another, although the inner portion44, outer portion46, and radial portion48may have a non-uniform thickness as described is certain embodiments discussed below. For instance, the inner portion44may have a thinner thickness than the radial portion48, and the radial portion48may have a thinner thickness than the outer portion46. As shown inFIG. 6, the inner portion44of the flange26is formed to have an inner or inward facing side thereof in a plane P tangent with or encompassing the first axial end38of the hub body36.

Due to the shape and configuration of the flange26relative to the hub24and friction ring22, when the brake disc20is undergoing a braking application, the flange26is loaded in bending M rather than in tension as the friction ring22expands outward and does not transfer all of the force directly to the hub24, such that the press-fit between the hub24and the axle is maintained. In other words, during thermal loading of the friction ring22, the press-fit of the hub24to the axle is maintained by preventing the radially outward expansion of the hub24. The displacement and stress of the brake disc20under loading are shown inFIGS. 7 and 8, respectively, with the different cross-hatching indicating areas of varying displacement or stress. InFIG. 7, as well as the other figures showing displacement discussed below, the brake disc20is shown under load in a deformed state and illustrates the flange26under the bending moment M. Accordingly, the flange26connecting the friction ring22to the hub24allows the brake disc20to handle higher thermal loading while still maintaining the press fit. In a conventional monoblock brake disc, the friction ring pulls directly on the spokes thereby pulling the hub away from the axle and relieving the press fit. During the operation of the brake disc20, the radial expansion of the friction ring22acts to bend or “straighten” the flange26such that only a portion of the radial expansion of the friction ring22is transferred to the hub24.

Referring toFIGS. 9-11, a further embodiment of a brake disc20ais disclosed. The brake disc20aof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, but includes a reduced thickness radial portion48. As depicted inFIGS. 9-11, in the present embodiment, the inner portion44, outer portion46, and radial portion48have a non-uniform thickness, with the inner portion44having a greater thickness than the radial portion48, and the radial portion48having a smaller thickness than the outer portion46. Moreover, as shown inFIG. 9, the inner portion44of the flange26is formed to have an inner or inward facing side thereof to lie in a common plane P tangent with or encompassing the first axial end38of the hub body36. The displacement and stress of the brake disc20aunder loading are shown inFIGS. 10 and 11, respectively, with the different cross-hatching indicating areas of varying displacement or stress.

Referring toFIGS. 12-14, another embodiment of a brake disc20bis disclosed. The brake disc20bof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, except for the connection of the outer portion46of the flange26to the friction ring22. In particular, the outer portion46of the flange26is connected to the inner surface32of one annular member28by a single row of pin fins34and to the inner surface32of the other annular member29by two rows of pin fins34. Additionally, the flange26has a substantially uniform thickness from the outer portion46to inner portion44and through the radial portion48. The radial portion48tapers outwardly to the outer portion46at a slight angle relative to the outer hub periphery39of the hub body36of the hub24. The displacement and stress of the brake disc20bunder loading are shown inFIGS. 13 and 14, respectively, with the different cross-hatching indicating areas of varying displacement or stress.

Referring toFIGS. 15-17, yet another embodiment of a brake disc20cis disclosed. The brake disc20cof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, except for the connection of the outer portion46of the flange26to the friction ring22. In particular, the outer portion46of the flange26is connected to the inner surfaces32of each annular member28,29by three rows of pin fins34. Additionally, the flange26has a substantially uniform thickness from the outer portion46to inner portion44and through the radial portion48. The radial portion48extends radially outward at a slight taper or angle relative to the outer hub periphery39of the hub body36of the hub24as best illustrated inFIG. 15, and the inner portion44of the flange26is formed to have an inner or inward facing side thereof to lie in a common plane P tangent with or encompassing the first axial end38of the hub body36. The displacement and stress of the brake disc20cunder loading are shown inFIGS. 16 and 17, respectively, with the different cross-hatching indicating areas of varying displacement or stress.

Referring toFIGS. 18-19, yet a further embodiment of a brake disc20dis disclosed. The brake disc20dof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, but the flange26is reduced in overall thickness and exhibits a generally uniform thickness except where the outer portion46connects to the radial portion48and where the inner portion44connects to the hub24. Additionally, the inner portion44extends axially past the first axial end38of the hub body36and exhibits a generally arcuate shape. The radial portion48thereafter is formed to be generally parallel to the outer hub periphery39of the hub body36of the hub24as best illustrated inFIG. 18. The displacement of the brake disc20dunder loading is shown inFIG. 19with the different cross-hatching indicating areas of varying displacement.

Referring toFIGS. 20-21, an alternative embodiment of a brake disc20eis disclosed. The brake disc20eof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, but the flange26has a substantially uniform thickness from the outer portion46to the inner portion44and through the radial portion48. The radial portion48extends radially outward at a slight taper or angle relative to the outer hub periphery39of the hub body36of the hub24as best illustrated inFIG. 20and the inner portion44of the flange26is formed to have an inner or inward facing side thereof to lie in a common plane P tangent with or encompassing the first axial end38of the hub body36. The displacement of the brake disc20eunder loading is shown inFIG. 21with the different cross-hatching indicating areas of varying displacement.

Referring toFIGS. 22-23, a further alternative embodiment of a brake disc20fis disclosed. The brake disc20fof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, expect that the flange26is connected to the hub24at a position axially spaced from the first axial end38of the hub body36of the hub24and extends outward from the outer hub periphery39of the hub body36. In particular, the radial portion48tapers outwardly to the outer portion46at a slight angle relative to the outer hub periphery39of the hub body36of the hub24. Additionally, the flange26has a substantially uniform thickness from the outer portion46to the inner portion44and through the radial portion48. The displacement of the brake disc20funder loading is shown inFIG. 23with the different cross-hatching indicating areas of varying displacement.

Referring toFIGS. 24-25, a further embodiment of a brake disc20gis disclosed. The brake disc20gof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, but the flange26includes a thicker radial portion48that narrows to the outer portion46. Further, the radial portion48tapers outwardly to the outer portion46at a slight angle relative to the outer hub periphery39of the hub body36of the hub24, and the inner portion44of the flange26is formed to have an inner or inward facing side thereof to lie in a common plane P tangent with or encompassing the first axial end38of the hub body36. The displacement of the brake disc20gunder loading is shown inFIG. 25with the different cross-hatching indicating areas of varying displacement.

Referring toFIGS. 26-27, another embodiment of a brake disc20his disclosed. The brake disc20hof the present embodiment is similar to the brake disc20shown inFIGS. 5-8andFIGS. 22-23, expect the flange26is connected to the annular member28of the friction ring22rather than being connected to the pin fins34. The flange26may also be connected to the other annular member29. Further, the flange26is connected to the hub24at a position axially spaced from the first axial end38of the hub body36of the hub24and tapers at an angle toward annular member28and extends outward from the outer hub periphery39of the hub body36. In particular, the radial portion48tapers outwardly to the outer portion46at a slight angle relative to the outer hub periphery39of the hub body36of the hub24. The flange26has a substantially uniform thickness from the outer portion46to the inner portion44and through the radial portion48. The displacement of the brake disc20hunder loading is shown inFIG. 27with the different cross-hatching indicating areas of varying displacement.

Referring toFIGS. 28-29, yet another embodiment of a brake disc20iis disclosed. The brake disc20iof the present embodiment is similar to the brake disc20shown inFIGS. 5-8, but the flange26has a substantially uniform thickness from the outer portion46to the inner portion44and through the radial portion48. The radial portion48extends generally parallel to the outer hub periphery39of the hub body36of the hub24as best illustrated inFIG. 28and the inner portion44of the flange26is formed to have an inner or inward facing side thereof to lie in a common plane P tangent with or encompassing the first axial end38of the hub body36. The displacement of the brake disc20iunder loading is shown inFIG. 29with the different cross-hatching indicating areas of varying displacement.

Referring toFIG. 30, a further embodiment of a brake disc20jis disclosed. The brake disc20jof the present embodiment is similar to the brake disc20shown inFIG. 5-8. The flange26of the brake disc20j, however, generally extends from a middle portion of the hub24, i.e., between the axial ends of the hub24. More specifically, the inner portion44of the flange26generally extends perpendicularly from the midpoint of the hub24. A generally C-shaped radial portion48transitions from the inner portion48and then transitions to the outer portion46, which extends to a position laterally between the annular members28,29of the friction ring22. Thus, the inner portion44and the outer portion46are generally aligned with each other (as shown in cross-section) in a direction that extends perpendicularly and radially outward from the hub24with the C-shaped radial portion48extending between the inner and outer portion44,46.

While embodiments of a railway vehicle brake disc were provided in the foregoing description, those skilled in the art may make modifications and alterations to these embodiments without departing from the scope and spirit of the invention. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The invention described hereinabove is defined by the appended claims and all changes to the invention that fall within the meaning and the range of equivalency of the claims are to be embraced within their scope.