HK40002274B - Axle-mounted brake disk for a rail vehicle - Google Patents

Description

Axle-mounted brake discs for rail vehicles

Technical Field

The invention relates to an axle-mounted brake disc for a rail vehicle.

Background Art

This type of axle-mounted brake disc for rail vehicles is typically made of a cast material, such as gray cast iron. Two friction rings, arranged parallel to each other and spaced apart, are connected to each other via ribs extending in the direction of the axis of rotation of the axle-mounted brake disc. The ribs are typically identical in design. In particular, the diameters of many of the ribs connecting the friction rings are equal.

In this case, the arrangement of the ribs relative to one another is usually optimized with a view to simple and as flawless a cast as possible, in order to thereby keep the production costs low.

A disadvantage of the shaft-mounted brake discs known from the prior art is their high mass. For example, a shaft-mounted brake disc made of grey cast iron with an outer diameter of 590 mm and a width of 170 mm (at this width the friction ring thickness is 25.5 mm) has a mass of more than 140 kg.

In this regard, there is a need for an improved shaft-mounted brake disc that has a reduced mass while maintaining the same performance.

Cooling capacity is crucial to maintaining the same effectiveness of this shaft-mounted brake disc.

Summary of the Invention

The object of the present invention is to provide a shaft-mounted brake disc which is lighter than conventional shaft-mounted brake discs and which has the same performance as these types of shaft-mounted brake discs.

To this end, the present invention proposes an axle-mounted brake disc for rail vehicles, which has two friction rings arranged parallel to each other and spaced apart, and is connected to each other by a plurality of ribs extending in the direction of the rotation axis of the friction rings, characterized in that at least a portion of the ribs are configured with mutually different cross-sections, wherein at least one cross-section of the ribs of a first subset configured as support elements for transmitting the pressing force is not less than a minimum cross-section, and at least one cross-section of the ribs of a second subset for radiating thermal energy is less than the minimum cross-section, wherein the minimum cross-section is determined by the necessary stability with respect to mechanical loads, which are applied to the two friction rings during braking and must be borne by the ribs of the first subset.

It has surprisingly been shown that the design of the shaft-mounted brake disc proposed by the invention allows the production of such a shaft-mounted brake disc with reduced mass while maintaining the same performance by adapting the ribs, in particular with regard to their diameter.

The shaft-mounted brake disk according to the present invention comprises two friction rings arranged parallel to each other and spaced apart, the friction rings being connected to each other by a plurality of ribs extending in the direction of the rotational axis of the friction rings. The invention is characterized in that at least some of the ribs are configured with mutually different cross-sections, wherein at least one cross-section of the ribs of a first subset configured as support elements for transmitting the pressing force is not less than a minimum cross-section, and at least one cross-section of the ribs of a second subset configured for radiating thermal energy is less than the minimum cross-section.

In a shaft-mounted brake disk designed in this way, the ribs are now divided into thermally active ribs and mechanically active ribs according to their assigned tasks. Due to their different diameters, it is possible to increase the rib packing density and thus increase the cooling surface.

Increasing the cooling channel area is an important factor in improving the cooling capacity, so that by increasing the cooling channel area, it is possible to use a shaft-mounted brake disc with a width of, for example, 110 mm instead of a conventional shaft-mounted brake disc with a width of 140 mm, which results in a 30% reduction in mass.

Reducing the mass of the axle-mounted brake disk has the advantage that the load capacity of the rail vehicle can thereby be correspondingly increased and the proportion of mass that is not damped by the elastic suspension can also be reduced.

By designing a portion of the ribs to have a cross-section that is not less than a predetermined minimum cross-section, these ribs can be used to relieve mechanical loads and the remaining ribs can be used primarily for radiating heat energy. As a result, the diameter of these ribs primarily used for radiating heat energy can be smaller than the minimum cross-section required for transmitting the mechanical compressive force.

According to an advantageous embodiment variant, a plurality of ribs of the first subset of ribs are arranged radially one behind the other relative to the axis of rotation of the friction ring.

Preferably, a plurality of ribs in the second subset of ribs are also arranged radially one after the other relative to the axis of rotation of the friction ring. This ensures that, when manufacturing a mold for a shaft-mounted brake disc, the molding sand can effectively fill the mold and ensure a high-quality structure and surface formation.

Furthermore, this radial arrangement of the ribs can achieve a higher rib density than a staggered rib arrangement with comparable mold quality.

According to another advantageous variant embodiment of the invention, the number of ribs of the second subset arranged radially one after the other is greater than the number of ribs of the first subset arranged radially one after the other.

Thus, the design of the second subset of ribs with reduced cross-sections enables a larger number of ribs to be molded in a radial arrangement, thereby further increasing the cooling channel area.

In order to optimize the utilization of the rib arrangement surface on the mutually facing inner sides of the friction ring, according to another preferred embodiment variant, radially arranged rows of ribs designed as supporting elements and radially arranged rows of ribs for radiating thermal energy are arranged alternately alongside each other in the circumferential direction.

According to another preferred variant embodiment, the cross section of each rib of at least one rib subset is configured to gradually increase toward the outer edge of the friction ring.

In another preferred embodiment variant of the present invention, another possible approach to increasing the cooling channel area is achieved by making the ribs closer to the inner edge of the friction ring longer than the ribs closer to the outer edge. Accordingly, the thickness of the friction ring is correspondingly reduced in the region of its inner edge.

In addition to increasing the cooling channel area, ventilation is thereby improved in the region of the friction ring inner diameter.

In a special variant embodiment of the shaft-mounted brake disc according to the invention, the ratio of the cross section of the ribs designed as support elements to the cross section of the ribs for radiating thermal energy is 3:2.

Here, the cross section of the rib is preferably round. It is also conceivable to design the cross section of the rib as an ellipse or a polygon.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereinafter, preferred embodiments will be explained in detail with reference to the accompanying drawings.

The accompanying drawings show:

FIG1 is a schematic cross-sectional view of a partial section of the inner side of a friction ring, including ribs extending from the inner side of the friction ring;

2 is a schematic sectional view of a section of a shaft-mounted brake disc in a section parallel to the axis of rotation of the shaft-mounted brake disc and extending radially relative to the axis of rotation of the shaft-mounted brake disc.

DETAILED DESCRIPTION

In the following description of the drawings, terms such as "up," "down," "left," "right," "front," and "rear" are merely exemplary representations and positions of the shaft-mounted brake disc, friction ring, ribs, support elements, etc., as selected in the corresponding drawings. These terms should be understood as non-restrictive; that is, these relationships may vary depending on different operating conditions or mirror-symmetrical designs.

1 and 2 show respective sections of an axle-mounted brake disc 1 for rail vehicles. The axle-mounted brake disc 1 comprises two friction rings 2 arranged parallel to each other and spaced apart. The friction rings 2 are connected to each other, in particular as a single piece, by a plurality of ribs 3, 4 extending in the direction of the axis of rotation and thus perpendicular to the friction surfaces of the friction rings 2.

In this case, the shaft-mounted brake disc 1 is connected via one or more connecting elements, for example in the form of retaining plates or brake disc drums, to a hub or a shaft, also not shown, on the vehicle side.

1 , a subgroup of ribs 3 and 4 are formed with mutually different cross-sections Q ₁ , Q ₂ , Q ₃ , Q ₄ , Q ₅ . The ribs of the subset G ₁ , designated by the reference numeral 3 , have cross-sections Q ₁ , Q ₂ , Q ₃ , Q ₄ that are greater than or equal to a predetermined minimum cross-section Q _min .

This minimum cross section Q _min is determined by the necessary stability with respect to the mechanical loads which are applied to the two friction rings 2 during the braking process and which must be absorbed by the ribs 3 .

The second group of ribs, designated by reference numeral 4, serves for radiating heat energy. The cross-section _Q5 of these ribs ₄ of the second subset G2 is smaller than the minimum cross-section _Qmin .

This measure makes it possible to increase the cooling channel area of the shaft-mounted brake disk 1 by providing the ribs 4 , which are not necessary from a mechanical point of view, between the friction rings 2 .

As shown in FIG. 1 , the ribs 3 of the first subset G ₁ are preferably arranged radially one behind the other relative to the axis of rotation of the friction ring 2 .

The ribs 4 of the second subset _G2 are also preferably arranged such that a respective row of such ribs 4 is arranged radially one after the other relative to the axis of rotation of the friction ring 2. This allows, in particular, simple mold production for casting such a shaft-mounted brake disk 1.

As is further shown by way of example in FIG. 1 , the number of ribs 4 of the second subset G ₂ arranged radially one behind the other is greater than the number of ribs 3 of the first subset G ₁ arranged radially one behind the other.

This can be achieved by designing the ribs 4 of the second subset G ₂ to have a smaller cross-section Q ₅ . The higher density of the ribs 4 achieved in this way correspondingly results in an increased cooling channel area of the shaft-mounted brake disc 1 .

In order to achieve the highest possible density of ribs 3 and 4 and the resulting large cooling channel area, radially arranged rows of ribs 3 designed as support elements and radially arranged rows of ribs 4 for radiating heat energy are arranged alternately side by side in the circumferential direction. Furthermore, the side-by-side arrangement of ribs 3 and 4 of different configurations allows for a uniform distribution of compressive forces by the ribs 3 designed as support elements.

However, other arrangements of the ribs 3 , 4 are also conceivable. What is important here is the greatest possible density of the ribs 3 , 4 and a sufficient number of ribs 3 designed as supporting elements to transmit the contact pressure to the friction ring 2 .

To further increase the cooling channel area, as shown in Figure 1 , the cross-section of at least one of the ribs 3, 4 in each subset _G1 , _G2 is configured to gradually increase toward the outer edge of the friction ring 2. In the variant embodiment shown in Figure 1 , the ribs 3 configured as support elements have different cross-sections _Q1 , _Q2 , _Q3 , and _Q4 . The ribs 4 used for radiating thermal energy have a constant cross-section _Q5 .

FIG2 shows another possible approach for increasing the cooling channel area of a shaft-mounted brake disc 1. As can be clearly seen here, the length _L1 of the ribs 3 and 4 near the inner edge 5 of the friction ring 2 is greater than the length _L2 of the ribs 3 and 4 near the outer edge 6 of the friction ring 2. Accordingly, the thickness _d2 of the friction ring 2 decreases accordingly near its inner edge 5.

In FIG. 2 , only the two innermost ribs 3 have a greater length than the ribs 3 closer to the outer edge 6 of the shaft-mounted brake disc 1 . However, it is also conceivable to design the thickness of the friction ring 2 such that it decreases continuously from the thickness D ₁ in the region of the outer edge to the thickness D ₂ in the region of the inner edge 5 , and the length L of the ribs 3 , 4 increases continuously from the outside to the inside accordingly.

It has proven particularly advantageous if the cross-section of the ribs 3 designed as support elements to the cross-section of the ribs 4 for radiating heat energy is in a ratio of 3:2. Thus, for example, the cross-section of the ribs 3 designed as support elements is 12 mm, while the cross-section of the ribs 4 for radiating heat energy is 8 mm.

The cross-sectional contour of the ribs 3, 4 is preferably round, as shown in Figure 1. However, it is also conceivable to form the ribs 3, 4 with an elliptical or polygonal cross section.

Reference Signs List

1 shaft-mounted brake disc

2 friction rings

3 tendons

4 tendons

5 Inner edge

6 Outer Edge

Q Cross section of the rib

Q _min minimum cross section

G ₁ Group 1

G ₂ Group 2

L ₁ Length of the reinforcement bar

L ₂ Length of the reinforcement bar

d ₂ Thickness of friction ring

Claims (6)

1. An axle-mounted brake disc for a rail vehicle, comprising two friction rings (2) arranged parallel to each other and spaced apart, the friction rings being connected to each other by a plurality of ribs (3, 4) extending in the direction of the rotational axis of the friction rings (2), characterized in that at least some of the ribs (3, 4) are designed with mutually different cross-sections ( _Q1 , _Q2 , _Q3 , _Q4 , _Q5 ), wherein at least one cross-section of the ribs (3) of a first subset ( _G1 ) designed as supporting elements for transmitting contact pressure is not less than a minimum cross-section ( _Qmin ), and at least one cross-section of the ribs (4) of a second subset ( _G2 ) for radiating thermal energy is less than the minimum cross-section ( _Qmin ), wherein the minimum cross-section (Qmin) is determined by the necessary stability with respect to mechanical loads which are applied to the two friction rings (2) during braking and which must be absorbed by the ribs (3) of the first subset ( _G1 ), wherein the cross-section of the ribs (3) of the first subset ( _G1 ) is not less than a minimum cross-section (Qmin _). ) are arranged radially in sequence relative to the rotation axis of the friction ring (2); multiple ribs (4) of the second subset (G ₂ ) are arranged radially in sequence relative to the rotation axis of the friction ring (2); the number of ribs (4) of the second subset (G ₂ ) arranged radially in sequence is greater than the number of ribs (3) of the first subset (G ₁ ) arranged radially in sequence. 2. The shaft-mounted brake disc according to claim 1, characterized in that radially arranged rows of ribs (3) configured as supporting elements and radially arranged rows of ribs (4) for radiating thermal energy are arranged alternately side by side in the circumferential direction. 3. The shaft-mounted brake disc according to claim 1 or 2, characterized in that the cross section of the ribs (3, 4) of at least one of the subsets ( _G1 , _G2 ) is configured to gradually increase toward the outer edge of the friction ring (2). 4. A shaft-mounted brake disc according to claim 1 or 2, characterized in that the length (L1) of the ribs (3, 4) close to the inner edge (5) of the friction ring ( ₂ ) is greater than the length (L2) of the ribs (3, ₄ ) close to the outer edge (6) of the friction ring (2), wherein the thickness (d2) of the friction ring ( ₂ ) decreases accordingly near its inner edge (5). 5. The shaft-mounted brake disc according to claim 1 or 2, characterized in that the ratio of the cross-section of the ribs (3) configured as support elements to the cross-section of the ribs (4) for radiating heat energy is 3:2. 6. The shaft-mounted brake disc according to claim 1 or 2, characterized in that the cross section of the ribs (3, 4) is circular, elliptical or polygonal.