EP2807010A1

EP2807010A1 - Component made of fiber-reinforced plastic for rail-fixing systems for rail vehicles

Info

Publication number: EP2807010A1
Application number: EP13701238.1A
Authority: EP
Inventors: Michael Harrass; Dietmar Becker; Bernd Schulte
Original assignee: Vossloh Werke GmbH
Current assignee: Vossloh Werke GmbH
Priority date: 2012-01-26
Filing date: 2013-01-18
Publication date: 2014-12-03
Also published as: CN104093541A; WO2013110558A1; RU2014134725A; DE202013012093U1; US20140371373A1

Abstract

The invention relates to a component for rail fixing systems, said component being made of a fiber-reinforced plastic which consists of a base plastic and reinforcing fibers incorporated into said base plastic. The component according to the invention can be produced from plastic inexpensively and allows the combination of a low component weight with a mechanical load-bearing capacity which is optimally adapted to the respective requirement while having a wide freedom of design. This is achieved in that the component is produced using the injection molding compounding process, and the length of the reinforcing fibers is at least 200 μm on average.

Description

COMPONENTS MANUFACTURED FROM FIBER-REINFORCED PLASTIC FOR SYSTEMS FOR FIXING RAILS TO RAIL VEHICLES

The invention relates to plastic

Components for systems for fastening rails for rail vehicles.

Modern rail fastenings, especially in the field of heavy goods transport or at

High speed lines are used regularly include various made of plastic

Components for supporting and guiding the to

serve to fasten the rail.

Components of the type in question can be

be formed plate-shaped, for example. Such plate-shaped components for rail fasteners include the so-called in the jargon

"Guide plates", "angled guide plates",

"Shims", "intermediate plates",

"Pressure distribution plates" or "ribbed plates".

Guide plates support when fully assembled

Fixing system from the rail to be fastened from the side and absorb the lateral forces when driving over the respective attachment point occur. In addition, the guide plates can be used as a support for each spring element, which needed to hold down the rail in fully assembled system

elastic hold down forces on the rail foot

applies. For this purpose, on the in

Assembly position free top of the guide plates one or more form elements may be formed in or at which the respective spring element is guided so that it maintains its desired position even under the loads occurring in practice. At the concerned

Form elements may be depressions, such as grooves, holes or other recesses or depressions, in which the spring element or a for clamping the

Spring element provided clamping means when finished

mounted system at least partially sitting. Furthermore, the form elements as compared to the

Main plane of the surface of the guide plate projecting ribs, webs or other elevations may be formed on which the spring element is supported in the manner of attacks or laterally guided.

In the case that the guide plate as so-called

"Angled guide plate" is formed, in addition to the underside of the guide plate is a in

Longitudinal direction of the guide plate extending paragraph be formed, which sits positively in the mounting position in a correspondingly shaped recess of the substrate. In this way, the position of the guide plate is fixed transversely to the longitudinal extent of the rail. Shims, intermediate plates, pressure distribution plates or ribbed plates are used in rail fastening systems of the type in question to the at

Driving over the attachment point formed with such a fastening system in the direction of gravity loads to transfer over a large area and evenly on the ground on which the

Attachment point is erected. Depending on the

respective local conditions and their

Mounting position within the respective

Rail fastening system they extend for this purpose, at least over the measured transverse to the longitudinal extent of the rail width of the rail foot or are laterally beyond. The relevant plates are either directly on the respective substrate or are supported on one or more intermediate layers on the ground. Also are made of different plates and made of elastic material

Layers multilayer packages formed by the one, on the one hand, a uniform distribution of the loads occurring and on the other hand, for a long time

Lifespan of the rail to be fastened required elasticity, required elastic compliance of the attachment point is ensured in the direction of gravity.

Ribbed plates make a special case of

plate-shaped components for rail fasteners. At its free in mounting position top are two parallel aligned, extending in the longitudinal direction of the rail to be fastened ribs

trained, which between themselves the AufStandfläche limit, on which stands in mounting position, the rail to be fastened with its rail. The ribs are spaced apart from each other so that they guide the rail laterally and when driving over the formed by the respective rail fastening system

Receive attachment points occurring transverse forces.

In addition to the plate-shaped components, depending on the particular local conditions or the technical requirements imposed on the respective rail fastening, for example, plastic insulation elements are required. These insulating elements serve to each made of conductive material

existing components of the fastening system or the rail to be fastened itself to isolate against the ground on which the rail is mounted.

Likewise, adapter pieces or eccentric body can

Plastic used in rail fasteners to adjust the position of each to be fastened rail for adjusting the track of the track to which the rail to be fastened.

Regardless of which of the above-mentioned components is concerned, the existing plastic components of a rail fastening system in practical use must not only withstand the high static and dynamic loads that occur when driving over the respective attachment point, but also robust against abrasive wear and insensitive against temperature changes, liquids and others

Be environmental influences. At the same time, the existing plastic

Components of a rail fastening system have a low weight and have a high dimensional stability. For this purpose, for example, in the

respective underground on which the

Rail fastening system to be built,

associated underside of the plate elements recesses formed and formed a rib structure.

By taking advantage of all design options, this results in a filigree shaping of modern panel components, characterized by locally minimized wall thicknesses and frequent wall thickness changes, which places high demands on production technology.

In order to meet the requirements placed on their load capacity, in the prior art for components that are used in rail fasteners, by

Glass fiber reinforced plastics used.

On the one hand, the demands for minimized

On the other hand, the requirements are constantly increasing, the mechanical properties of plastic-made components for

Rail fastening systems of the type in question are asked, the object of the invention was a component for rail fastening systems

create, which can be inexpensively made of plastic, and in which as far as possible freedom of design a low weight with optimally adapted to the respective requirements mechanical

Resilience are combined. According to the invention this object has been achieved by a device having the features specified in claim 1.

Advantageous embodiments and variants of the invention are set forth in the dependent claims and are hereinafter referred to as the general inventive concept in

Individual explained.

A device according to the invention is thus made of a fiber-reinforced plastic, which is made of a base plastic and incorporated therein

Reinforcing fibers consists. According to the invention, the preparation is by application of injection molding

Compounding takes place, according to the invention, the length of the present in the finished component reinforcing fibers averages at least 200 μκι.

By the term "average length" it is meant always that mean value determined in the usual way by simply dividing the total length of the fibers detected in a sample by the number of fibers concerned.

In principle, all thermoplastics can be used as base plastic for a component according to the invention

Use plastics. These include in particular

Polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polyoxymethylene (POM), acrylonitrile-butadiene-styrene (ABS), polybutylene terephthalate (PBT) and polyethylene (LDPE / HDPE) and blends thereof such as blends and compounds. According to the invention are particularly high-load, filigree molded plastic components for

Rail fastening systems made using "Injection Molding Compounding". This method is also referred to in practice as "IMC method". As in the article by M. SIEVERDING, DR. E. BÜRKLE, R. ZIMMET "IMC technology opens up new application areas",

Kunststoffe international 8/2005, Carl Hanser Verlag, Munich,

The IMC process allows the fabrication of reinforced large volume components by combining the advantages of injection molding and extrusion. The peculiarity of the IMC process consists in the fact that a twin-screw extruder is used, with which in the process the respectively desired material mixture

can be compounded individually. In this way, the base plastic for embossing or optimizing certain properties directly during processing, for example, reinforcing fibers, fillers or present in the form of granules plastic additives, so-called "masterbatches" are supplied to their contents

Colorants or additives are higher than in the

End use.

Surprisingly, it has been shown by the

inventive use of the IMC process for the production of fiber-reinforced plastic components for rail fasteners succeeds, much larger

Reinforcing fiber lengths in the finished device to

obtained as is possible in the conventional production of components for the rail fastening of fiber-reinforced plastic granules. Larger lengths of the introduced into the base material reinforcing fibers mean here in the center

standing application "Components for

Rail fasteners "in the first place higher

Strengths in the respective component. Furthermore

The advantages of the longer reinforcing fibers made possible by the use of the IMC process according to the invention are that, with the same volume fraction, a smaller number of reinforcing fibers is required in order to achieve the desired mechanical characteristics. It consists of manufacturing technology point of view

particular advantage is that with a smaller number of reinforcing fibers of the abrasive tool wear is significantly reduced, since only the abutting against the wall of the tools fiber ends have an abrasive effect.

It could be proven that the length of the

Reinforcing fibers in accordance with the invention produced by the IMC process, plate-shaped

Components of the type described above regularly

at least 25% longer than identically shaped but produced from conventional granules

Components used in granule production

Reinforcing fibers has been added. It could be shown that the mean of the fiber lengths of plate elements produced according to the invention regularly corresponded to at least twice the average of the lengths of the fibers present in conventionally produced components.

Specifically, in the inventive manner by the IMC method for the attachment of rails certain plate components, such as guide plates, shims, Intermediate plates, pressure distribution plates or ribbed plates, are produced, in which the

Amplification fiber length on average regularly at least 200 μτ and more, in particular at least 300 μπι and more, is. In practical experiments could regularly be achieved fiber lengths that are greater than 350 μπι average, the obtained

Amplification fiber lengths in the range of 15 - 2000 μπι, in particular 20 - 2000 μηι, were.

A significant advantage in terms of

Uniformity of property distribution

According to the invention components is that when produced in accordance with the invention components for

Rail fasteners the dispersion of the fiber length

is minimized. So results for the lengths of

Reinforcing a particularly narrow

Distribution curve. For example, according to the

Invention introduced as reinforcing fibers conventional glass fibers in the respective base plastic. However, it is also possible in accordance with the invention

Base plastic to supply other high-performance fibers. In addition to aramide and carbon fiber materials, these include, for example, metal and ceramic fibers.

In order to ensure the wetting with the base plastic, the reinforcing fibers introduced according to the invention in the IMC process can be provided with a type of a

Adhesive acting sizing be provided. These include, for example, mechanically, adhesively and chemically acting sizes, such as polyurethanes and silanes. By coating with such a sizing an improved embedding of the reinforcing fibers in the inventive application of the IMC process

Polymer matrix of the base plastic allows.

The addition of chopped glass fibers (short and long glass) or glass beads as hybrid reinforcing material as bulk material is also possible.

Due to the improved by the inventive application of the IMC process raw material properties can be a particularly filigree shape of the invention

Components are realized. Finely structured ribs can thus be formed, which lead to a significant saving of material, without including the

mechanical properties, in particular the

Component strength and stiffness, suffer. In general, the use of the IMC process can save plastic as a result of the improved plastic material, since the required stability is achieved even with minimized component volumes. Thus, by consistently applying the possibilities opened up by the use of the IMC method according to the invention, reductions of the component volume by up to 25% compared with the volume of conventionally produced components can be achieved.

Those for practical use each specifically

required properties of inventive

Rail fastener components can be adjusted by the addition of additives and fillers. Thus, components according to the invention of low weight and optimum mechanical properties can be

cost-effectively made of plastic by the respective used base plastic additives specifically and

Fillers are added by the properties, such as

- the nature and influence of crystallinity (see

suitable additives are known per se, used for this purpose in the prior art

Crystallizing agents, such as finely dispersed particles, e.g. Silica),

the weathering resistance (additives suitable for this purpose are known antioxidants or carbon black used for this purpose in the state of the art),

the mechanical resistance (suitable additives are reinforcing fibers or particles),

the thermal properties (additives suitable for this purpose are known heat stabilizers used for this purpose in the prior art),

- The electrical properties (suitable for this purpose

Additives are electrically conductive metal particles that give the plastic material a certain conductivity),

- the tribological properties (suitable for this purpose)

Additives are known per se for this purpose, which can be incorporated into the plastic lubricant, such as MoS2 or graphite),

the fire behavior (suitable additives for this purpose are per se known flame retardants, such as, for example, halogen or aluminum compounds), hygroscopy (suitable additives for this purpose are hydrophobic constituents known per se), or

- The resistance to hydrolysis (this suitable additives are per se known antioxidants) are selectively modified.

In this case, by adding nucleating agents or crystallization formers to the base plastic as additives, its microstructure formation can be improved. Examples of suitable additives include

finely dispersed particles. By adding such additives, the demolding temperature can be reached faster, and consequently the cycle times can be shortened.

It is also possible by adding

Impact additives (elastomeric moieties), such as ethylene-propylene-diene monomer (EPDM), other elastomers or polyethylene, to improve the toughness and thus the durability of the components. Specifically, additives can be incorporated which

Avoid diffusion by covering the surface of the component. Among the suitable ones

Additives include hydrophobic additives.

Furthermore, it is conceivable, as additives special

Marking agents, such as fluorescent agents to introduce into the base plastic, which allow a clear identification of the respective component. The presence of such markers allows the user to easily control whether it is the component supplied to him is an original or an imitation which may not fulfill the required qualities.

Also, you can use the base plastic as additives

Compatibilizer for the specific combination of two per se incompatible polymers, e.g. PE / PP are added to PA. Particularly suitable as intermediaries are so-called "compatibility mediators", such as

ambivalent substrates.

Finally, it is conceivable to addit to the

Avoid subsequent conditioning. In this way it is possible, for example, to surround the plate elements made of PA plastic usually necessary for the purpose of setting a certain moisture content conditioning. So can

For example, suitable additives, such as polar plasticizers, cause no water to be included but still achieve the properties that result from a conventionally conditioned component.

Examples which may be mentioned of the base plastic are fillers and additives to be added according to the invention

organic materials such as carbon fibers, wood flour, aramid fibers added for reinforcement, and inorganic materials such as titanium dioxide, MoS 2, talc, mica, silicic acid, iron sulfite added to adjust slip properties, and for example, Na-phenylphosphinate as a nucleating agent is added. The fillers and additives and other additives mentioned in the preceding paragraphs can be added in a particularly simple manner to the base plastic used in each case if the IMC method is used to produce the respective component for rail fastening. By applying this method, the respective fillers and additives can be easily alone or in combination with reinforcing fibers in the

Bring in basic plastic.

According to a further embodiment of the invention, the properties of the components according to the invention for a rail fastening can be further optimized by the fact that the base plastic used in each case

Blowing agent is added for foaming. By the

Base plastic at least on certain sections or in total as foam with a comparably high

Pore content is formed, is a reduced

Weight achieved at the same time high stiffness.

At the same time, by foaming the

Base plastic and the associated

Volume increase the time required for the filling of the respective mold, be shortened, whereby in the result a shortening of the cycle time required for the production of the components is achieved. Also results from the foaming minimizing the delay during solidification of the components and it can not

Avoiding sink marks, which may otherwise occur as a result of shrinkage occurring in the course of solidification. The effect of the foaming process in the base plastic driving force also allows large flow path lengths. The control of the foaming process can by

Application of the gas backpressure method known per se, in which the gas flowing into the respective molding tool plastic is opposed to a gas pressure to ensure a uniform mold filling and to prevent premature foaming.

A high gas loading of the melt with chemical and physical blowing agents leads to the formation of an integral foam structure in the molding interior. When forming such a structure can be dispensed with the inevitable during conventional injection molding pressure phase. This means lower cavity pressure, resulting in lower required closing forces for

Locking the tool and as a result a significant reduction in wear. As a result of the minimization of the holding pressure time shorter cycle times and, consequently, a higher productivity can be achieved.

Depending on the particular geometry of the component to be produced, its weight can be reduced by up to 15% compared to an identically shaped but conventionally produced component due to the use of base plastic-foaming additives and the porous cell structure achieved thereby. At the same time is foaming a

Material savings achieved, in turn, lower

Unit costs. Overall, the addition according to the invention of a foaming agent to the base plastic results in a more uniform material shrinkage and, consequently, a better quality of the parts. Especially the plate-shaped components according to the invention for

Rail fasteners are suitable for the reduction of the density of the base plastic obtained by the addition of foaming agents, since they allow "breathing tools" with which highly foamed integral structures and, concomitantly, higher specific bending stiffness can be achieved.

For the purposes of the invention, physically or chemically acting foaming agents can be used. The physically acting foaming agents include

for example, nitrogen or carbon dioxide. It is also possible to use the MuCell process, which is known per se, for example in the Krauss Maffei

Technologies GmbH "CellForm - foaming process for injection molding". As a chemical blowing agent comes, for example

Sodium bicarbonate in question.

The invention is based on a

Exemplary embodiments illustrative drawing explained in more detail.

Figures 1 and 2 of the drawing show, respectively

schematically and in a transverse to the longitudinal extent of the respective rail S partially cut view

Conventionally constructed system for fastening a rail S. With the first system shown in Figure 1 is a

Rail S fixed on a solid, formed for example by a concrete sleeper underground U. The

System comprises a shim 1, on the two

Angled guide plates 2,3 are supported. The

Angled guide plates 2,3 define between them one formed on the top of the shim 1

AufStandfläche 4, on which a layer consisting of elastic material layer 5 is located. On the elastic layer 5 in turn is the foot 6 of the rail S, which laterally borders on each of its associated contact surface of the angle guide plates 2.3. On the angled guide plates 2,3 each have a W-shaped, conventionally shaped spring element 7,8 is mounted, which acts with the free ends of its spring arms on the rail 6 and so applies the necessary for holding down the rail S elastic hold-down force. The spring elements 7,8 are each by means of a sleeper screw 9,10, which through an opening of the

inserted respective angle guide plate 2.3 and screwed into a seated in the underground U, not visible here dowel, braced against the substrate U.

The system shown in Fig. 2 for securing the

Rail S is also conventional in terms of its components. Thus, in the here formed as a concrete sleeper solid underground U are two

Shoulders 20,21 molded, in each case one

Angled guide plate 22,23 is supported. The

Angle guide plates 22,23 also define between a AufStandfläche 24, which is formed here at the top of the solid substrate U. On the

Aufstand surface 24 is an elastic layer 25, on the in turn, a pressure distribution plate 26 is placed. On the pressure distribution plate 26 is a second elastic layer 27, on top of which the rail S is with its rail 28. As in Fig. 1

As shown, the angle guide plates 22,23 are on the side of the rail 28, so that they derive the transverse forces occurring when driving over the rail S by a rail vehicle in the solid surface ü. On the angled guide plates 22,23 is also here as in the embodiment of FIG. 1 each have a W-shaped spring element 29,30, also referred to as a clamp, supported by means of a respective

Threshold screw 31,32 braced against the ground U.

The measures provided for the attachment of the rail S.

Components "shim 1" as well

"Angled guide plates 2,3" of the rail fastening system shown in Fig. 1 and the "angle guide plate 22,23" and "pressure distribution plate 26" of the rail fastening system shown in Fig. 2 have each been prepared by applying the IMC method of a polyamide plastic, the in each case used IMC compounder as reinforcing fiber glass fibers have been added.

For comparison, conventionally made of glass fiber reinforced polyamide plastic granules, similar shaped components have been used.

It was in each case the length of those present in the present invention by using the IMC process Reinforcing fibers determined. The following lengths could be determined (data in μηι):

According to the invention made conventionally produced from components by using the plastic granulate IMC process

components

Minimum 18, 86 13, 60

Mean 377, 19 175, 45

Maximum 1832, 99 629, 82

Claims

PATENT APPLICATIONS

1. component for rail fastening systems,

made of a fiber-reinforced plastic, made of a base plastic and in it

incorporated reinforcing fibers,

d a d u r c h g e k e n c i n e s, it is by oulding it by application of the Injection

Compounding is made and the length of the reinforcing fibers is on average at least 200 μπι.

2. Component according to claim 1, d a d u r c h

However, the length of the reinforcing fibers is on average greater than 350 .mu.m.

3. The component according to claim 1 or 2, in which the length of the reinforcing fibers is in each case in the range from 15 to 2000 μm.sup.a.

4. The component according to one of the preceding claims, characterized in that the base plastic polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polyoxymethylene (POM), acrylonitrile-butadiene-styrene (ABS),

Polybutylene terephthalate (PBT), polyethylene

(LDPE / HDPE) or a mixture of these

Plastics is.

5. The component according to one of the preceding claims, characterized in that the reinforcing fibers glass fibers, aramid,

Carbon, metal or ceramic fibers are.

6. The component according to one of the preceding claims, characterized in that the base plastic is at least one additive for .alpha

Adjustment of a specific property of the fiber reinforced plastic is added.

7. The component according to one of the preceding claims, wherein a base metal contains at least one filler.

8. The component according to one of the preceding claims, characterized in that it is plate-shaped.

9. The component according to claim 8, characterized in that it is a guide plate for laterally guiding a rail.

10. The component according to claim 8, d a d u r c h

It is not possible that it is a shim for laying a rail.

11. The component according to claim 8, d a d u r c h

There is an intermediate plate which is provided between the respective rail to be fastened and one lying on the respective substrate

Washer to be placed.