阅读说明：本技术 弹簧元件和阻燃的覆盖层 (Spring element and flame-retardant covering layer ) 是由 J·克恩 M·皮卡德 M·迈尔 E·吕埃森 于 2020-03-13 设计创作，主要内容包括：本发明涉及一种用于轨道车辆的减振器和/或悬架的弹簧元件(1),所述弹簧元件具有至少一个弹性的阻尼体(2)和至少一个设置在所述阻尼体(2)上的阻燃的覆盖层(3),其中,所述覆盖层(3)具有至少一个补偿区(4),所述补偿区(4)在弹簧元件(1)的负载状态下被挤压在一起,从而阻止覆盖层(3)形成褶皱,所述覆盖层(3)与阻尼体(2)无法分离地交联成复合元件(6)。所述本发明此外涉及一种覆盖层以及弹簧元件或覆盖层的应用。(The invention relates to a spring element (1) for a shock absorber and/or a suspension of a rail vehicle, comprising at least one elastic damping body (2) and at least one flame-retardant cover layer (3) arranged on the damping body (2), wherein the cover layer (3) comprises at least one compensation zone (4), wherein the compensation zone (4) is pressed together in the loaded state of the spring element (1) in order to prevent the cover layer (3) from forming wrinkles, wherein the cover layer (3) is connected to the damping body (2) in a non-separable manner to form a composite element (6). The invention further relates to a cover layer and to the use of a spring element or a cover layer.)

1. Spring element (1) for a shock absorber and/or suspension, comprising at least one elastic damping body (2) and at least one flame-retardant cover layer (3) arranged on the damping body (2), characterized in that the cover layer (3) comprises at least one compensation zone (4), the compensation zone (4) being pressed together in the loaded state of the spring element (1) in order to prevent the cover layer (3) from forming folds, and in that the cover layer (3) is connected to the damping body (2) in a non-separable manner to form a composite element (6).

2. The spring element (1) according to claim 1, characterized in that the compensation zone (4) is formed by an interruption (5) of the cover layer (3) and/or in that the cover layer (3) is formed in the compensation zone (4) to be thinner than the average layer thickness of the remaining regions of the cover layer (3).

3. A spring element (1) according to claim 1 or 2, wherein the compensation zone (4) has or consists of a groove (13) or grooves (13).

4. Spring element (1) according to one of the preceding claims, characterized in that the damping body (2) is made of at least one rubber material, the rubber material of the damping body (2) having a higher elasticity than the covering layer (3).

5. Spring element (1) according to one of the preceding claims, characterized in that the covering layer (3) is composed partly or largely of at least one elastomer.

6. Spring element (1) according to one of the preceding claims, characterized in that the covering layer (3) consists partly or largely of neoprene.

7. Spring element (1) according to one of the preceding claims, characterized in that the cover layer (3) comprises at least one flame retardant agent and/or acid acceptor.

8. A spring element (1) according to claim 7, wherein said at least one flame retardant and/or acid acceptor is one selected from the group or one selected from the group comprising a combination of two or more than two flame retardants and/or acid acceptors: phosphorus-containing compounds, in particular ammonium polyphosphate (APP), nitrogen-containing compounds, in particular melamine, polyol compounds, in particular pentaerythritol, phosphate-containing plasticizers, in particular discomol DPO, inorganic flame retardants and/or acid scavengers of the borate type, in particular zinc borate, hydroxides, in particular aluminum hydroxide and/or magnesium hydroxide and/or boehmite, antimony compounds, in particular antimony trioxide and/or antimony pentoxide, oxides, in particular magnesium oxide, nanoclays, graphite, in particular expandable graphite.

9. The spring element (1) according to one of the preceding claims, characterized in that the cover layer (3), in particular outside the compensation zone (4), has an average layer thickness of 1mm to 5mm, in particular the cover layer (3) is designed to be at most 4mm thick, in particular the cover layer (3) is designed to be at most 3mm thick, in particular the cover layer (3) is designed to be at most 2mm thick, in particular the cover layer (3) is designed to be at most 1mm thick.

10. Spring element (1) according to one of the preceding claims, characterized in that the cover layer (3), in particular in the installed state of the spring element (1), forms the outer layer of the spring element (1).

11. Spring element (1) according to one of the preceding claims, characterized in that the at least one compensation zone (4) is partially or completely closed in the loaded state, in particular in the maximally loaded state, so that an outwardly closed covering layer (3) is present.

12. Spring element (1) according to one of the preceding claims, characterized in that the spring element (1) is a spring element (1) for a shock absorber and/or suspension of a rail vehicle.

13. Spring element (1) according to one of the preceding claims, characterized in that the spring element is at least one spring element (1) of the group of the following highly loaded components: such as a primary conical spring (7), a secondary additional spring, a shaft spring and/or an air spring bellows.

14. Flame-retardant cover layer (3), in particular for a spring element, characterized in that the cover layer (3) has at least one compensation zone (4).

15. Flame-retardant covering layer (3) according to claim 14, characterized in that the compensation zone (4) is formed by an interruption (5) of the covering layer (3).

16. Flame-retardant covering layer (3) according to one of the preceding claims, characterized in that the covering layer (3) has at least two covering layer regions (11) which are arranged spaced apart from one another in the unloaded state of the covering layer (3) by means of free spaces (5).

17. Flame-retardant covering layer (3) according to one of the preceding claims, characterized in that the covering layer (3) is designed to be thinner in the compensation zone (4) than the average layer thickness of the remaining regions of the covering layer (3).

18. Flame-retardant covering layer (3) according to one of the preceding claims, characterized in that the covering layer (3) consists partly or largely of an elastomer.

19. Flame-retardant covering layer (3) according to one of the preceding claims, characterized in that the covering layer (3) consists partly or largely of neoprene.

20. Flame-retardant covering layer (3) according to one of the preceding claims, characterized in that the covering layer (3) comprises at least one flame retardant and/or acid acceptor.

21. Flame-retardant cover layer (3) according to claim 20, characterized in that the at least one flame retardant and/or acid acceptor is one selected from the group or one selected from the group comprising a combination of two or more than two flame retardants and/or acid acceptors: phosphorus-containing compounds, in particular ammonium polyphosphate (APP), nitrogen-containing compounds, in particular melamine, polyol compounds, in particular pentaerythritol, phosphate-containing plasticizers, in particular discomol DPO, inorganic flame retardants and/or acid scavengers, in particular zinc borate, aluminum hydroxide (ATH) and/or magnesium hydroxide.

22. Use of a spring element (1) according to one of the preceding claims for a shock absorber and/or suspension of a rail vehicle, preferably the spring element is at least one spring element (1) of the group of highly loaded components: such as a primary conical spring (7), a secondary additional spring, a shaft spring and/or an air spring bellows.

23. Use of a flame-retardant coating (3) according to one of the preceding claims for coating spring elements (1) of a vibration damper and/or suspension for a rail vehicle.

24. Use according to claim 23, characterised in that the spring element is at least one spring element (1) of the group of highly loaded components: such as a primary conical spring (7), a secondary additional spring, a shaft spring and/or an air spring bellows.

Technical Field

The invention relates to a spring element for a shock absorber and/or a suspension, having at least one elastic damping body and a flame-retardant cover layer arranged on the damping body.

The invention further relates to a flame-retardant covering for a spring element.

Background

In the rail vehicle sector in particular, the demands on the fire protection properties of the spring elements used are particularly high. For example, specific fire protection requirements according to DIN EN45545-2 must be met. However, since the mechanical requirements on the spring element, in particular in the region of the chassis, are particularly high, it is often necessary to use damping bodies which can absorb and thus damp impacts and/or oscillations particularly well. Thus, a damping body of this elastic design can be produced, for example, from a rubber mixture with a relatively high proportion of combustible substances, for example natural rubber. However, spring elements comprising damping bodies with a high proportion of natural rubber do not comply with DIN EN45545-2 on account of their poor fire-protection properties.

Damping bodies made of alternative rubber mixtures with poor combustibility are already known. The rubber mixture may contain, for example, flame-retardant additives, by means of which the fire behavior of the damping body is improved. The spring element generally exhibits the disadvantage that the mechanical properties of the damping body are negatively influenced. It may then happen, for example, that the required service duration of the spring element can no longer be reached because of excessive wear due to damaged mechanical properties, so that the spring element must be replaced earlier.

Furthermore, attempts have been made to protect the damping body against fire by means of a flame-retardant covering layer. However, the cover layers used here have likewise poor mechanical properties, which can lead to the flame-retardant cover layer likewise wearing off relatively quickly and thus also not reaching the required service life of the spring element here. This can be attributed, for example, to the fact that the cover layer is less elastic than the damping body covered by said cover layer and therefore folds are formed in the cover layer in the event of a compression of the damping body. As a result, cracks and other damage can form on the cover layer in the event of prolonged use, with the result that there is the risk that the spring element cannot comply with the required fire protection properties.

Disclosure of Invention

It is therefore an object to provide a spring element and/or a flame-retardant covering layer, wherein the use properties of the spring element and/or the flame-retardant covering layer are improved compared to previously known spring elements and/or flame-retardant covering layers.

According to the invention, the solution of the object is provided by a spring element having the features according to claim 1. In particular, a spring element of the type mentioned at the outset is proposed for solving the above-mentioned object, wherein the cover layer has at least one compensation region which is pressed together in the loaded state of the spring element, so that the cover layer is prevented from forming wrinkles. In particular, the formation of folds in the most loaded state of the spring element can be prevented. This has the advantage that a known type of damping body (which can be made, for example, from a rubber mixture based on natural rubber and therefore has good mechanical properties) can be used in the spring element, which nevertheless complies with DIN EN45545-2 due to the flame-retardant covering layer. At the same time, the cover layer now also meets the mechanical requirements that are precisely in rail vehicle construction and accumulate as a result of the high loads acting on the suspension and/or damper components. Due to the at least one compensation zone, the upper surface contour of the spring element is given a specific geometry by means of which the cover layer is prevented from forming folds in the loaded state of the spring element. The compensation zone thus acts in the manner of a buffer zone into which the cover layer can be pushed without forming wrinkles when the damping body is compressed, so that excessively high mechanical loads of the cover layer, which may lead to excessively rapid wear or damage of the cover layer, can be avoided.

Advantageous embodiments of the invention are described below, which embodiments may, alone or in combination with the features of further embodiments, optionally in combination with the features according to claim 1.

According to a particularly advantageous further development, the compensation region can be formed by a discontinuity in the cover layer. Preferably, the cover layer can have at least two cover layer regions which, in the unloaded state of the spring element, are arranged at a distance from one another by a free space. The cover layer regions can thus be pushed together under load due to the free space provided between them, so that the formation of wrinkles is prevented. Under the load of the spring element, the flame-retardant covering layer is closed, so that the flame-retardant effect of the covering layer remains intact. Alternatively or additionally, the cover layer is designed in the compensation zone to be thinner than the average layer thickness of the remaining regions of the cover layer. The effect in this embodiment is based substantially on the same principle as the embodiments described in between.

In particular, the cover layer may have a plurality of compensation regions.

In order to be able to achieve a particularly good mechanical loadability of the spring element, the cover layer and the damping body are connected to form a composite element in a non-separable manner. It can therefore be better avoided that the covering layer loosens from the damping body, in particular in the case of a high load of the spring element, so that the fire protection effect of the covering layer is lost. The crosslinking of the cover layer with the damping body can be carried out, for example, by vulcanization, which is known per se. Preferably, the formation of covalent bonds between the cover layer and the damping body can be achieved by means of said cross-linking. Inseparable crosslinking in the sense of the present invention may mean that the two parts cannot be separated from one another without damage.

According to a further advantageous embodiment of the spring element, the damping body can be made of a rubber material, wherein the rubber material of the damping body can have a higher elasticity than the covering layer. It is thus possible to use previously known damping bodies made of rubber mixtures which are inherently combustible and which do not retain the required fire-protection properties without a covering layer.

According to a particularly advantageous embodiment, the at least one cover layer can be composed partially or largely of an elastomer. In particular, the at least one cover layer may be at least partially made of neoprene. It has been shown that especially neoprene has particularly good fire protection properties. However, the use of neoprene for the covering layer is in principle unsuitable, since the mechanical properties of said neoprene with respect to strength and ductility are not sufficient to withstand high loads, in particular in rail vehicles. Therefore, cracks in the cover layer may occur on the surface of the damping body coated with the chloroprene rubber-based cover layer. However, the formation of such cracks can be avoided due to the at least one compensation zone formed in the cover layer. Surprisingly, it can even be found that spring elements designed in this way have particularly good mechanical properties and, in addition, good fire protection properties.

In order to be able to better prevent the formation of undesired acids and/or the formation of toxic fumes in the event of a fire, the covering layer may comprise at least one flame retardant and/or acid acceptor. The at least one flame retardant and/or acid acceptor may for example be one selected from the group or a combination comprising two or more than two flame retardants and/or acid acceptors selected from the group: phosphorus-containing compounds, in particular ammonium polyphosphate (APP), nitrogen-containing compounds, in particular melamine, polyol compounds, in particular pentaerythritol, phosphate-containing plasticizers, in particular discomol DPO (langer low-temperature halogen-free phosphorus flame retardant, germany), inorganic flame retardants and/or acid scavengers of the borate type, in particular zinc borate, hydroxides, in particular aluminum hydroxide and/or magnesium hydroxide and/or boehmite (Boehmit), antimony compounds, in particular antimony trioxide and/or antimony pentoxide, oxides, in particular magnesium oxide, nanoclays (Nanoclay), graphite, in particular expandable graphite.

In order to be able to achieve good mechanical properties of the spring element and at the same time a longer service life of the spring element, the cover layer, in particular outside the compensation zone, may have an average layer thickness of 1mm to 5 mm. In particular, it can be provided that the cover layer is designed to be at most 4mm thick, in particular that the cover layer is designed to be at most 3mm thick, in particular that the cover layer is designed to be at most 2mm thick, in particular that the cover layer is designed to be at most 1mm thick.

According to a further advantageous embodiment, it can be provided that the cover layer, in particular in the installed state of the spring element, forms the outer layer of the spring element.

According to an advantageous further development of the spring element, the at least one compensation zone can be designed such that the compensation zone is partially or completely closed and/or pushed together in the loaded state, in particular in the maximally loaded state, so that an outwardly closed covering layer is present.

According to a particularly advantageous further development, the spring element can be a spring element of a damper and/or a suspension for a rail vehicle. The spring element may be, for example, at least one spring element of the group of highly loaded components: such as a primary conical spring, a secondary additional spring, an axle spring, and/or an air spring bellows.

The above object is furthermore achieved by a flame-retardant covering layer having the features of independent claim 11. In particular, to achieve the object, a flame-retardant cover layer for a spring element is proposed, wherein the cover layer has at least one compensation zone. This has the advantage that the cover layer does not have to be formed so elastically that the mechanical requirements are met due to its elasticity. Since the cover layer does not take over the suspension or damping action, it can be designed to be harder than the damping body on which it can be applied.

Advantageous embodiments of the invention are described below, which embodiments may, alone or in combination with the features of further embodiments, optionally in combination with the features according to claim 11. The advantages that apply with regard to the flame-retardant covering layer are essentially the same as already described with regard to the characteristics of the spring element.

According to a further development of the cover layer, it can be provided that the compensation region is formed by a discontinuity of the cover layer. Preferably, the cover layer has at least two cover layer regions which, in the unloaded state of the cover layer, are arranged at a distance from one another via a free space. In particular, the cover layer may have a plurality of compensation regions.

Alternatively or additionally, it can be provided according to a further embodiment that the cover layer is designed to be thinner in the compensation zone than the average layer thickness of the remaining regions of the cover layer.

According to a further advantageous embodiment of the flame-retardant covering layer, the covering layer can be made partially or largely of an elastomer, in particular of neoprene. It can be provided here that the test specimen representing the cover layer has a tensile strength of at least 4.0Mpa, in particular at least 5.0Mpa, in particular at least 6.0Mpa, in particular at least 7.0Mpa, in particular at least 8.0Mpa, in particular at least 9.0Mpa or more, preferably the tensile strength is tested according to the test method according to the ISO 37 and DIN 53504 standards.

Furthermore, it can be provided that the test specimen representing the cover layer has an elastic modulus (100%) of at least 1.0Mpa, in particular at least 1.2Mpa, in particular at least 1.4Mpa or more and/or that the cover layer has an elastic modulus (200%) of at least 1.6Mpa, at least 1.8Mpa, in particular at least 2.0Mpa or more and/or that the cover layer has an elastic modulus (300%) of at least 2.0Mpa, at least 2.2Mpa, in particular at least 2.4Mpa, in particular at least 2.6 or more.

Furthermore, it can be provided that the coating has an ozone crack rating of 0, in particular the ozone crack is determined according to the test standard DIN ISO 1431-1.

Furthermore, it can be provided that the maximum value of the average heat release (MAHRE value) of the samples representing the cover layer is at most 90kWm^-2In particular a maximum of 75kWm^-2In particular a maximum of 50kWm^-2In particular a maximum of 40kWm^-2In particular a maximum of 30kWm^-2In particular a maximum of 25kWm^-2In particular a maximum of 20kWm^-2Or less, preferably said MAHRE value is according to EN ISO5660-1 test specification at an irradiance of 25kW/m²Is determined in the case of (1).

Furthermore, it can be provided that the test specimen representing the cover layer has a hazard rating (CITG value) of at most 1.8, in particular at most 1.5, in particular at most 1.2, in particular at most 1.0 or less, and/or a smoke density of at most 600, in particular at most 300, in particular at most 200, in particular at most 100 or less, preferably the hazard rating (CITG value) and/or the smoke density (Ds, maximum) according to the EN ISO 5659-2 test method at an irradiance of 25kW/m²Is determined in the case of (1).

According to a further advantageous embodiment, it can be provided that the cover layer comprises at least one flame retardant and/or acid acceptor, in particular that the at least one flame retardant and/or acid acceptor is one selected from the group or one selected from the group consisting of two or more flame retardants and/or acid acceptors in combination: phosphorus-containing compounds, in particular ammonium polyphosphate (APP), nitrogen-containing compounds, in particular melamine, polyol compounds, in particular pentaerythritol, phosphate-containing plasticizers, in particular discomol DPO, inorganic flame retardants and/or acid scavengers of the borate type, in particular zinc borate, hydroxides, in particular aluminum hydroxide and/or magnesium hydroxide and/or boehmite, antimony compounds, in particular antimony trioxide and/or antimony pentoxide, oxides, in particular magnesium oxide, nanoclays, graphite, in particular expandable graphite.

In this case, for example, it can be provided that the mass fraction of the at least one flame retardant and/or acid acceptor in the composition of the cover layer is 30% to 70%, the mass fraction of the chloroprene rubber is 30% to 70%, and the mass fraction of the at least one additional component is 0% to 15%, the sum of all components resulting in at least 60% and up to 100%. Preferably, the cover layer can have a crosslinking agent as at least one additional component.

Furthermore, the above object may be achieved by the application of a spring element as described and claimed herein for a shock absorber and/or suspension of a rail vehicle. Preferably, the spring element may be at least one spring element of the group of highly loaded components: such as a primary conical spring, a secondary additional spring, an axle spring, and/or an air spring bellows. As already mentioned at the outset, it is necessary, even in the rail vehicle sector, to use components which are subjected to high mechanical loads and at the same time have the required fire protection properties. The spring element described and claimed herein is therefore particularly suitable for use in the rail vehicle field.

Furthermore, the above object is achieved by the use of a flame-retardant coating as described and claimed herein for coating spring elements of a damper and/or suspension for a rail vehicle. Preferably, the spring element may be at least one spring element of the group of highly loaded components: such as a primary conical spring, a secondary additional spring, an axle spring, and/or an air spring bellows.

Drawings

The invention will now be described in more detail by means of a number of examples, to which, however, the invention is not limited. Further embodiments result from the combination of features of one or more of the claims with one another and/or with individual or several features of the described embodiments. In the figure:

fig. 1 shows an overview of a longitudinally sectioned embodiment variant of the spring element according to the invention in the unloaded state, wherein the spring element is designed as a conical spring,

fig. 2 shows a detail of the compensation zone of the unloaded spring element in fig. 1 in the cover layer, wherein the cover layer is formed by a recess in the cover layer,

figure 3 shows an overview of the embodiment variant of the spring element according to the invention in figure 1, this time in a loaded state, cut longitudinally,

fig. 4 shows a detail of the compensation zone in the cover layer of the loaded spring element from fig. 3, wherein the cover layer regions of the cover layer previously separated by free space are pushed together in the region of the compensation zone, so that a closed cover layer is formed.

Detailed Description

Fig. 1 and 4 show possible embodiment variants of a spring element, indicated as a whole by 1. The embodiment variant shown in the figures relates to a conical spring 11. The invention can thus be implemented, for example, in a component for a primary suspension in the chassis of a rail vehicle. However, the invention can also be implemented, for example, in further components, in particular in suspensions and/or dampers for rail vehicles. The embodiments shown are therefore to be understood as merely possible examples and are therefore primarily intended merely to better illustrate the invention.

The spring element 1 has a plurality of elastic damping bodies 2, which each support a flame-retardant cover layer 3.

Suitable materials and compositions for making the damping body 2 are known and may also be used in connection with the present invention. Damping bodies 2 made of one or more rubber materials are known, for example. In particular damping bodies 2 which are at least partially made of natural rubber are known, which however do not exhibit the fire protection properties required for rail vehicles, since they can burn too easily.

As shown in fig. 1 and 3, the damping bodies 2 can be arranged concentrically about the longitudinal axis 12 of the spring element 1. Alternatively or in addition thereto, the damping bodies may be of conical design, wherein the cross-sectional diameter of the damping bodies decreases, in particular continuously decreases, in the compression direction 10.

Each damping body 2 has a cover layer 3 on its outer side. Furthermore, a large number of materials and compositions are already known for the production of flame-retardant cover layers 3, which are likewise used according to the invention. The flame-retardant cover layer 3 can be harder and/or less elastic than the damping body 2, for example. It can be provided that the damping body 2 has a lower modulus of elasticity than the cover layer 3. Thus, under normal mechanical loads, for example in the case of a compression of the spring element 1, the cover layer 3 will wear out more quickly than the damping body 2. This results in that the required service life of the spring element 1 cannot be achieved due to wear of the cover layer 3.

For example, it can be provided that the cover layer 3 is made at least partially or largely of at least one elastomer, in particular of a rubber compound. A particularly advantageous material for the production can be, for example, neoprene from the abovementioned compositions, since the fire-resistant properties of said neoprene are suitable for producing spring elements in accordance with DIN EN 45545-2.

As can be seen in fig. 2 and 4, the cover layers 3 each have a compensation region 4. The compensation region 4 is provided to prevent the formation of folds and/or cracks in the cover layer 3 as a result of the load acting on the cover layer 3 when the spring element 1 is loaded.

The compensation region 4 of the cover layer 3 of the spring element 1 is formed by at least one interruption in the cover layer 3, so that in the unloaded state of the spring element 1 and/or in the unloaded state of the cover layer 3, a free space 5 is present between at least two cover layer regions 11 of the cover layer 3. Thus, as long as there is a load, the formation of wrinkles in the cover layer 3 is prevented by the compensation zone 4. The recess 13 can thus be formed by the interruption.

The damping body 2 can be protected against fire by the cover layer 3, in particular independently of the flammability of the damping body 2, in that the cover layer 3 shields the damping body 2 from the outside.

The cover layer 3 and the damping body 2 can be cross-linked to one another to form a composite element 6, so that no damage-free separation and/or detachment of the cover layer 3 from the damping body 2 occurs.

Two adjacent damping bodies 2 can be supported and/or separated from each other by a support element 8, which can have the shape of a sleeve, for example. The spring element 1 has a plurality of, in particular sleeve-shaped, supporting elements 8. The support element 8 may have a conical shape, in particular a shape corresponding to the shape of the damping body 2. The support element 8 may be hard, in particular made of metal, for example.

The cover layer 3 can have a layer thickness of 1mm to 5mm, in particular a conventional layer thickness outside the compensation zone 4. In this case, if the layer thicknesses are not exactly uniform, an average layer thickness may be used, for example. In particular, the cover layer 3 can be designed to be at most four millimeters thick, in particular at most three millimeters thick, in particular at most two millimeters thick, in particular at most one millimeter thick.

As can be seen in fig. 3 and 4, the cover layer 3 is at least partially, preferably completely, closed in the loaded state of the spring element 1. Since the individual cover layer regions 11 of the cover layer 3 are pushed together and at least partially lie against one another, the cover layer 3, which is preferably closed to the outside, is formed in the loaded state.

The spring element 1 can have a receptacle 9 which preferably extends in the longitudinal direction, in particular along a longitudinal axis 12 of the spring element 1, and is used for coupling the spring element to a further component, for example a bogie.

The at least one free space 5 can be formed, for example, in the form of a recess 13 or a plurality of recesses 13 in the cover layer 3. The grooves 13 may for example be arranged parallel and/or transversely to each other. Preferably, the groove 13 can extend transversely, in particular perpendicularly, to the compression direction of the spring element 1. The recesses 13 can be formed, for example, so as to be distributed over almost the entire surface of the spring element 1 formed by the cover layer. Preferably, a recess 13 can be formed between two adjacent support elements 8. The recesses 13 can thus each be formed between two cover layer regions 11 of the cover layer 3.

The term free space 5 may relate to a material void in the cover layer 3.

In the case of the spring element 1 being designed as a conical spring 7, the recesses 13 can be designed concentrically.

Particularly preferably, the free space 5, in particular the groove 13 or the grooves, can have a constant or substantially constant width, respectively. The distance between the two cover layer areas, i.e. the free space 5 of the compensation area 4, can thus always be the same or almost always be the same. In particular, the deviation between the smallest distance and the largest distance is at most 25%, in particular at most 20%, in particular at most 15%, in particular at most 10%, in particular at most 5%.

In the case of the lowest load, the free space 5, in particular the recess 13, can be closed such that in the flame-retardant covering layer 3 at least one closing layer thickness of 1mm is present in the region pushed together. The remaining layer thickness of the cover layer 3 outside the region pushed together can differ from this, in particular can be thicker than the closure layer thickness, for example at least 3mm, in particular 4 mm. During the subsequent compression, the groove 13 is then completely closed and/or the contact width, which is at least 1mm wide, "migrates" within the pressed-together end faces and thus forms a closed fire protection cover.

The spacing between two adjacent cover layer regions 11 in the unloaded state may be at least 0.5mm, in particular at least 1mm, in particular at least 2mm, in particular at least 3mm, in particular at least 4mm, in particular at least 5 mm.

The invention therefore relates in particular to a spring element 1 for a shock absorber and/or a suspension of a rail vehicle, the spring element has at least one compressible, in particular combustible damping body 2 and at least one flame-retardant covering layer 3 at least partially covering the damping body 2, wherein the cover layer 3 has at least one compensation region 4 with at least two cover layer regions 11, the cover layer regions 1 are separated from each other by free spaces 5 in the unloaded state of the spring element, wherein the cover layer regions 11 are pressed together under the load of the spring element 1 in such a way that their edges partially or completely abut against one another, and thus forms a covering layer 3 which completely surrounds the damping body 2 and/or is covered at least in particular on the outside, said covering layer ensuring the desired fire protection.

List of reference numerals

1 spring element

2 damping body

3 coating layer

4 compensation zone

5 a breaking part; free space

6 a composite element; composite body

7 conical spring

8 a support element; cover

9 accommodating part

10 direction of compression

11 area of the cover layer

12 longitudinal axis of spring element

13 groove