DE19834704C2 - Friction ring or friction element for a friction brake, in particular a disc brake - Google Patents

Description

The invention relates to a friction ring or friction element for a brake disc, in particular especially for rail vehicles with a first structure that forms a supporting body det, and a second structure that represents a wear area.

Rail vehicles are a preferred area of application for the brake according to the invention.

In particular for high-speed rail transport, friction elements or friction rings are currently under development, which are used in shaft brake discs and wheel brake discs and consist of so-called ceramic matrix composite materials, so-called CMC materials. The friction rings for such friction brakes are predominantly made up of a homogeneous fiber structure and a ceramic matrix. Such "homogeneous friction rings" can consist of one of the structures listed below:

• - Carbon Fiber Fabrics
• - Short or long cut fibers
• - felting
• - Three-dimensional fabrics, preferably made of carbon fibers
• - Long-fiber pigtails

Fabric layer and long fiber braid friction rings or discs have a relatively high Strength and are therefore suitable for high mechanical stresses. Disadvantageous Friction layers made of these substances are the high wear and the tendency to oxidize and the poor heat conduction perpendicular to the tissue plane.

Short-cut fiber slices are tribologically superior because they have a lower one Wear, a more uniform coefficient of friction and good resistance to oxidation have, but they have significantly lower strengths. This is particularly the case with high speed and high braking torques critical. The heat conduction from Kurz Cut fiber layers are equally good in all spatial directions.

From US 5 242 746 is a friction element, in particular for high-performance brakes made of composite carbon material, which has a multilayer construction includes. The structure of each layer is determined by its texture  characterized. So-called rough textures are included Tissue segments and fine textures, including fiber segments, are distinguished.

In the case of the friction elements known from US Pat. No. 5,242,746, the mechanical and tribological properties of the friction elements or friction rings by means of the multilayer structure, each layer having a different one Had texture, namely the friction layer preferably a fine structure and Carrier layer preferably a coarse structure.

DE 44 38 456 discloses a friction unit comprising a core body and a Friction body has become known, both the core body and the friction body is constructed from carbon fiber materials into which liquid silicon is infiltrated. The Friction unit known from DE 44 38 456 also has different layers on, with DE 44 38 456 requiring that the different layers can be connected with a high-strength connection layer. The characteristics of the Friction elements that have become known from DE 44 38 456 are in essentially determined by the amount of silicon introduced.

DE 196 51 798 A1 describes a friction unit, in particular a brake disc known with at least one friction body and at least one molded body.

The friction body is made of plastic-fiber reinforced composite material firmly joined to the molded body so that at least part of the Shaped body forms an area of the friction surface, wherein the shaped body in Direction of the surfaces has normal higher heat conduction.

The object of the invention is now one compared to the previously cited state of the Technically improved embodiment of a friction ring or a brake disc, Specify especially for rail vehicles. In addition to high strength values the friction elements according to the invention should also be good Excellent friction properties with low wear and good Thermal conductivity in the axial direction, d. H. perpendicular to the friction surface. In particular Thermal conductivity is important for heat dissipation from the panes as it does otherwise heat build-up occurs in the friction zone.

According to the invention the object is achieved in that the friction ring or Friction element has a support body with a first structure, the fabric layers of carbon fibers and the second forming the wear area Structure carbon short cut fibers.  

In a particularly advantageous embodiment of the invention it is provided that the Friction ring or the friction element has a layer structure that has at least three Layers. The first and third layers have carbon Short cut fibers and the second layer at least partially made of a fabric Carbon fibers of the first structure.

Particularly good thermal conductivity properties are achieved when the support body forming second structure is interspersed with areas of the first structure.  

In a first embodiment it is provided that the one forming the support body first structure is formed in one piece.

Alternatively, the support body can be constructed in several parts. For example the fabric layers of the first structure consist of segment parts that overlap pend are stacked on top of each other.

There are several design variants for support bodies made up of segment parts. It can be provided that the segment parts or sectors overlap in order catch direction are arranged. Alternatively, the sectors can be radial and circular overlap. Combinations of the two variants described above are possible.

In order to improve the connection of the individual layer structures with one another seen that the first structure forming the supporting body and comprising tissue is provided with recesses in the structure forming the wear area interventions encompass short cut fibers and a positive connection form.

As an alternative to an embodiment of the support body with recesses, it can be pre-designed hen that the fabric layers of the first structure form a coarse-mesh network and in the space areas of the second structure comprising carbon Short cut fibers are stored.

A particularly good heat dissipation is achieved when the in the support body embedded areas of the second structure comprising short cut fibers in sliding Connected to the first and third layers. Those are particularly preferred conductive connections adjacent to cooling devices, such as cooling slit, arranged.

The friction ring according to the invention or the friction element according to the invention can be found in egg ner first embodiment of the invention be a shaft brake disc, which be in a special embodiment is designed as a ventilated shaft brake disc. At lüf Teten wave brake discs is advantageously provided that their cooling webs short include cut fibers.

As an alternative to the embodiment described above, it can be provided that the Friction ring or the friction element a wheel brake disc, preferably a vented Wheel brake disc is.  

In addition to the friction rings or friction elements according to the invention, the invention provides a method for producing such a friction element is also available. The Manufacturing process includes at least the three steps described below. The friction ring is preferably produced lying down and comprises on its underside a first layer comprising short cut fibers. To make the first layer the short cut fibers are mixed with plastic dough and poured into a mold. Fabric layers are placed on the first layer, using a liquid art fabric (resin) are soaked. In turn, a short is placed on this supporting body layer cut fiber mixture, as described in the first step, applied.

The further design of the brake discs then takes place as in conventional ones Shaft or wheel brake discs.

The invention will be described in more detail below using the figure as an example the.

Show it:

FIG. 1a is a shaft brake disk according to the invention;

FIG. 1b shows a wheel brake according to the invention;

FIG. 2a shows a section of a support layer which is made of overlapping sectors sammengesetzt;

2b shows an alternative embodiment of a detail of a support layer with overlapping structures.

Fig. 2c comprises a plan view of a brake disc, the support layer overlapping de structures;

Fig. 3a layer an uncooled shaft brake disk with recesses in the carrier, is introduced into the short cut fiber material;

FIG. 3b is a side view of a brake disc according to Fig. 3a;

Fig. 4a is a cooled shaft brake disc, in the cooling webs made of short cut sermaterial;

FIG. 4b is a ventilated wheel brake.

In Fig. 1a, a friction element according to the invention, namely a wave brake disc be shown, which is composed of three layers, namely a carrier layer 1 , which is essentially made of fabric and / or long fiber material, such as carbon material. The base layer with a fabric layer structure gives the disks a very high strength, so that they can withstand high mechanical stresses and are therefore suitable for introducing high braking torques. Due to the very high wear, a first and third layer 3 , 5 is applied to the support body made of fabric layer, which is composed essentially of short cut fibers. The wear layers are tribologically superior to the support body layer. They have lower wear, a more uniform coefficient of friction and good oxidation resistance. In contrast to the base layer, which essentially only conducts parallel to the plane of the fabric fibers, the thermal conductivity of these layers is equally good in all three spatial directions. Their lower strength is compensated for by the base layer 1 . The manufacture of such a wave brake disc shown in Fig. 1a can be achieved by first pouring the underside of such a wave brake disc into a mold, carbon short cut fibers are mixed in a plastic dough. On this first layer 3 , the base layer 1 is built up, consisting of fabric layers which are impregnated with liquid plastic. On the support body or the support layer 1 is followed by a third layer, namely the second wear layer 5 , which essentially again comprises a short cut mineral mixture.

Instead of a shaft brake disc, the friction element according to the invention can also be used to build up a wheel brake disc, as shown in FIG. 1b. This brake disc also has a support body 1 , which consists essentially of long-fiber carbon fibers forming the fabric layers, and on both sides of the support body 1 wear layers 3 , 5 , which are composed essentially of short cut fibers.

In FIGS. 2a to 2c alternative embodiments of the supporting body layer 1 are shown. Thus, the support body layer 1 as well as in a special embodiment, the wear layers may not be formed in one piece as a friction ring, but may be composed of several segments. The side view of a friction ring composed of different segments is shown in FIG. 2a. The individual support ring sectors 10.1 , 10.2 , 10.3 , which essentially comprise tissue elements, overlap in the regions 12.1 , 12.2 and 12.3 in the circumferential direction. Instead of a segmented structure that overlaps in the circumferential direction, as shown in FIG. 2a, the sectors 10.1 , 10.2 , 10.3 can be made even smaller, as shown in FIG. 2b. The individual tissue sectors then overlap both in the radial direction and in the circular direction and together form the support ring. A top view of an inventive friction member with a supporting body according to Fig. 2a or 2b, Fig. 2c. The wear layers 3 , 5 and the base layer 1 composed of individual segments 10.1 , 10.2 , 10.3 can be clearly seen.

In order to improve the cooling performance of the discs prepared from the inventive friction elements, the supporting body forming fabric layer 1 as shown in FIGS. 3a and 3b, recesses 20 may comprise, in the short-cut fiber regions, for example the wear layer 3, 5, preferably positively engage , It is particularly preferred if the recesses penetrate the entire support body 1 , so that a conductive, in particular a heat-conducting connection is formed between the two wear layers 3 , 5 by the short cut fibers embedded in the recesses 20 . The wear layers 3 , 5 preferably comprise 50% or more of the total disc thickness of the non-ventilated shaft brake disc constructed in advance of three layers.

Instead of short cut fibers, the recesses 20 , which act as cooling webs or heat conducting webs, can also consist of a mat or a felt.

In this way, a build-up of heat in the friction zone can be reduced, since the heat penetrates well through the base layer 1 and can be dissipated in the area of, for example, the outer wear layer 3 . Furthermore, the support ring 1 can be produced inexpensively by such a design, since only part of the support ring consists of expensive fabric layer material.

Furthermore, a certain topography of the cooling webs can be modulated in a very simple manner by a corresponding number and arrangement of the recess, and a very uniform thermal conductivity can be obtained in this way. The brake disc shown in FIGS . 3a and 3b is an unventilated full brake disc.

Instead of a configuration with recesses 20 in the support layer, it can alternatively be provided in an embodiment (not shown) that the fabric layers of the support body 1 only form a very coarse-meshed pattern. In the interstices of the pattern, fiber bundles of short-cut fibers or felts etc. can then be stored. The interstices then, like the recesses, ensure a sufficiently good thermal conductivity.

In addition to non-ventilated shaft brake disks and non-ventilated wheel brake disks, it is also possible, as in FIGS . 4a and 4b, to use the friction element according to the invention for the formation of ventilated shaft brake disks or ventilated wheel brake disks. FIG. 4a shows such a ventilated shaft Disc brakes 100. The ventilated shaft brake disk 100 has a central support body 102 comprising fabric layers and then two support layers 104 , 106 , which also comprise fabric coverings. Wear layers 108 , 110 , which essentially comprise short-cut fibers, are applied to the carrier bodies 104 , 106 . The cooling webs 112 , like the recesses 20 of the non-ventilated shaft brake disc, are constructed from short-cut fibers and therefore have good thermal conductivity. Alternatively, felts could be provided. In addition, in a particularly preferred embodiment, the base layers 104 and 106 can also have recesses, in particular in the area of the cooling webs 112 , into which short-cut fibers are embedded, so that a conductive connection between the wear layers 110 and 108 is provided. The heat can be emitted from the cooling webs 112 to the adjacent cooling devices, in the present case the cooling slots 114 .

The shaft brake disk is particularly preferably designed in such a way that the width B of one side of the shaft brake disk is 50% formed by the base layer 104 , 106 and the wear layer 108 , 110 .

In Fig. 4b a vented wheel brake is shown according to the invention, the wheel 200 of the friction brake comes with extensive substantially short cut fibers wear layer 202 to the plant. The carrier body 204 of the wheel brake disk in turn essentially has fabric layers made of long cut fibers. The wear layer 202 opposite is arranged on the base layer 204 in turn a layer 206 made up of short cut fibers. Variants of the base layer as well as recesses in the same can be carried out analogously to the examples described above, without explicit reference being made here again.

With the present invention, a new type of friction element is thus provided for the first time give, which is easy to manufacture, high mechanical stability and ge rings wear and good thermal conductivity in the axial direction. turned The friction element according to the invention can be set, for example, in waves brake discs or wheel brake discs, but also in high-speed gearboxes for Brakes.  

LIST OF REFERENCE NUMBERS

1

backing

3

.

5

first and third layers (wear layers)

7

bolt connection

10.1

.

10.2

.

10.3

Support ring sectors

12.1

.

12.2

.

12.3

overlapping areas

20

recesses

100

ventilated shaft brake disc

102

supporting body

104

.

106

roadbases

108

.

110

wear layers

112

cooling fins

200

Wheel center

202

.

206

wearing course

204

base course

Claims (13)

1. Friction element for a friction brake, in particular a brake disc with a first structure that forms a support body ( 1 , 102 , 204 ) and a second structure that forms a wear area ( 3 , 5 , 108 , 110 , 202 , 206 ), wherein the first structure forming the supporting body ( 1 , 102 , 204 ) comprises fabric layers made of carbon fibers and the second structure forming the wear area ( 3 , 5 , 108 , 110 , 202 , 206 ) comprises short-cut fibers, preferably made of carbon, characterized in that that the friction element comprises a layer structure with at least three layers, the first and third layers having wear layers comprising carbon short-cut fibers of the second structure and the second layer having a base layer comprising at least partially woven fabrics made of carbon fibers of the first structure and partially made of fibers of the second structure and wherein the first structure is constructed in several parts. 2. friction element according to claim 1, characterized in that the first structure forming the support body with regions of the second Structure is interspersed. 3. Friction element according to claim 1 or 2, characterized in that the first structure forming the supporting body is formed from overlapping segment parts ( 10.1 , 10.2 , 10.3 ). 4. Friction element according to claim 1 to 3, characterized in that segment parts of the first structure ( 10.1 , 10.2 , 10.3 ) overlap in the circumferential direction. 5. Friction element according to one of the preceding claims, characterized in that the segment parts ( 10.1 , 10.2 , 10.3 ) overlap radially and circularly. 6. Friction element according to one of the preceding claims, characterized in that in order to improve the connection of the individual structures to one another, the support structure ( 1 , 102 , 204 ) forming the first structure has recesses ( 20 ) into which portions of the second structure forming the wear area form-fitting intervention. 7. friction element according to one of the preceding claims, characterized in that the fabric layers of the first structure form a coarse mesh and in the gaps areas of the second structure comprising carbon short cut fibers are stored. 8. friction element according to one of the preceding claims, characterized in that the areas embedded in the second layer forming the supporting body the second structure comprising short cut fibers, in conductive connection with the first and third layers. 9. Friction element according to claim 8, characterized in that the conductive connection between the first and the third layer is formed adjacent to cooling devices ( 114 ). 10. friction element according to one of claims 1 to 9, characterized in that the friction element is a shaft brake disc. 11. friction element according to claim 10, characterized in that the shaft brake disc is a ventilated shaft brake disc that is connected to the Cooling bars include short cut fibers. 12. friction element according to one of claims 1 to 11, characterized in that the friction element is a wheel brake disc. 13. A method for producing a friction element according to one of claims 1 to 12, comprising at least the following steps:

• 1. 13.1 short cut fibers are mixed with a plastic dough and poured into a mold;
• 2. 13.2 over the layer formed according to step 13.1 , coarse-meshed net fabric layers soaked with liquid plastic are applied overlapping;
• 3. 13.3 a plastic dough mixed with short-cut fibers according to step 13.1 is again applied to the layer formed according to step 13.2 .