DE102019211604A1 - Method for manufacturing a bellows blank and an air spring - Google Patents

Abstract

Method for producing a bellows blank for an air spring (20), the bellows blank being wound together from at least a first elastomer layer (3) and a thread layer (4), a conveyor device (1) transferring the layers (3; 4) to a rotating winding mandrel ( 2) for winding and the winding mandrel (2) is arranged with its longitudinal axis (L) essentially at right angles to a conveying direction (10) of the conveying device (1), the first elastomer layer (3) being cut in the form of a parallelogram and thus on the Conveyor device (1) is deposited that two side lengths (a; c) of the first elastomer layer (3) are oriented obliquely to the longitudinal axis (L) of the winding mandrel (2) and an air spring (20) for a motor vehicle, comprising two connecting parts (21 ; 22) between which at least one thread-reinforced bellows (23) made of elastomeric material is clamped in a pressure-tight manner, the bellows (23) being formed from at least one first elastomer layer (3) and one thread layer (4) t, where two side lengths (a; c) overlap the first elastomer layer (3) in such a way that an overlap (34) of these side lengths (a; c) runs in a coaxial spiral shape around a longitudinal axis (LF) of the air spring (20).

Description

The invention relates to a method for producing a bellows blank according to the preamble of the independent method claim and an air spring according to the preamble of the independent device claim.

Air springs, which are clamped between a chassis and a body of a motor vehicle and have a thread-reinforced bellows, which in turn is fastened between a cover and a rolling piston, are known in a large number of designs.

To produce the bellows, a winding technique is used, such as that from U.S. 3,794,538 A is known. The bellows blank is wound together from several layers, the wound bellows then being expanded and vulcanized in order to produce the tubular bellows for the air spring. According to the prior art, a first rubber layer is first placed in a rectangular shape on a changing table, with a first and a second fabric layer subsequently being placed on the changing table, each of which is shaped as a parallelogram and aligned opposite to one another, with a second rubber layer finally being placed on the changing table is placed in a rectangular shape on the changing table. The layers are fed one after the other to a rotating winding mandrel, so that the layers are wound around the winding mandrel. As a result, a bellows blank is produced with an inner layer, two fabric layers with intersecting threads and an outer layer. The so-rolled bellows blank can then be expanded and vulcanized to form the finished bellows product.

The rectangular rubber layers are cut from a supply roll in such a width that they correspond to the circumference of the winding and a slight oversize. Consequently, there is an overlap line of the rubber layers in the wound bellows blank, which line runs parallel to the longitudinal axis of the bellows blank or the winding mandrel. This represents a local, longitudinal thickening of the rubber material.

If, instead of the two layers of fabric in the form of a parallelogram, a rectangular layer of fabric is placed on the wrapping table, so that its threads run parallel to the longitudinal axis of the winding mandrel, the fabric layer will overlap, which can also be taken from the wrapped blanket as a local, longitudinal thickening of the fabric layer.

• Durch die innere Druckbeaufschlagung des Balgs erfolgt eine Zwangsdehnung des Balgmaterials. Bei dem druckbeaufschlagten und somit bauchigen Balg müssen sich die axial verlaufenden Fäden möglichst gleichmäßig auf einen größeren Durchmesser anordnen. Örtliche Steifigkeitsunterschiede des Balgmaterials in Umfangsrichtung führen allerdings zu einer ungleichmäßigen Verteilung der Fäden. Stellen mit einer niedrigen Steifigkeit werden mehr ausgedehnt als benachbarte Stellen mit einer hohen Steifigkeit. Es besteht also die Gefahr, dass die axial verlaufenden Fäden unterschiedliche Abstände zu einander einnehmen und somit die Balgwand in Umfangsrichtung unterschiedliche Festigkeiten erhält. Wenn der Fadenabstand partiell doppelt so groß ist wie an anderen Stellen, dann kann das Material der Gummilagen dem Innendruck nicht mehr standhalten. Stattdessen wird das Gummimaterial durch die Fadenzwischenräume gedrückt und der Balg droht zu platzen.

In this way, a number of longitudinally extending overlaps of the rubber layers and the fabric layer, which can be present at different positions in the circumferential direction of the bellows blank, are disadvantageously created. However, these partial overlaps or thickenings are very bad for the bursting pressure properties of an axial bellows, which is intended to be effective as a cardanic fold of an air spring. When pressure is applied to the finished bellows with the disadvantageous overlaps, the following mechanism works:

• The internal pressurization of the bellows forces the bellows material to expand. In the case of the pressurized and thus bulbous bellows, the axially extending threads must be arranged as evenly as possible over a larger diameter. However, local differences in the rigidity of the bellows material in the circumferential direction lead to an uneven distribution of the threads. Locations with a low stiffness are expanded more than neighboring locations with a high stiffness. There is therefore the risk that the axially running threads take up different distances from one another and thus the bellows wall has different strengths in the circumferential direction. If the thread spacing is partially twice as large as in other places, then the material of the rubber layers can no longer withstand the internal pressure. Instead, the rubber material is pressed through the spaces between the threads and the bellows threatens to burst.

Against this background, it emerges that any overlap with a local accumulation of additional material brings about a significant increase in the circumferential stiffness. The more unevenly the bellows is constructed in the circumferential direction, the stronger the effects mentioned have on the bellows and the higher the risk of failure.

This is to be prevented by the fact that the facing edges of a layer overlap as little as possible and the overlaps of all layers should be distributed as evenly as possible in the circumferential direction so that no mutual reinforcement occurs. However, these are not satisfactory measures.

It is therefore the object of the invention to provide a method for producing a bellows blank which does not produce any disadvantageous longitudinal overlap of an elastomer layer and to provide an air spring for a motor vehicle, the axial bellows of which has an improved bursting pressure property.

The object on which the invention is based is achieved with the features of the independent claims.

According to the invention, a method for producing a bellows blank for an air spring is provided, the bellows blank being wound together from at least a first elastomer layer and a thread layer, a conveying device feeding the layers to a rotating winding mandrel for winding and the winding mandrel with its longitudinal axis essentially at right angles to a Is arranged conveying direction of the conveyor, wherein the first elastomer layer is cut in the form of a parallelogram and placed on the conveyor in such a way that two side lengths of the first elastomer layer are aligned obliquely to the longitudinal axis of the winding mandrel.

The first elastomer layer is cut from a supply roll at a predefined angle, i.e. at an angle, so that the parallelogram shape of this layer results. After the first elastomer layer has been deposited, the inclined section represents the side length of the first elastomer layer aligned at right angles to the longitudinal axis of the winding mandrel, while the inclined side line results from the unrolled length of the first elastomer layer from the supply roll. When the first elastomer layer is deposited, the inclined side lengths therefore run at an angle between 1 ° and 89 ° to the longitudinal axis of the winding mandrel.

The first parallelogram-shaped elastomer layer is deposited on the conveyor device in such a way that two side lengths are aligned at right angles to the winding mandrel and the other two side lengths are oblique to the winding mandrel. The first elastomer layer deposited in this way is fed to the winding mandrel by the conveying device, whereby the right-angled side lengths wind up in the circumferential direction and the inclined side lengths wind up in a spiral shape over the entire length of the bellows blank.

Since the right-angled side lengths of the first elastomer layer determine the circumference of the bellows blank, they are determined with a slight oversize, so that the inclined side lengths overlap due to the winding. This creates side edges from the lengths of the sides of the first elastomer layer, which create an adhesive and overlapping bond of the unvulcanized elastomer material of the first elastomer layer.

This adhesive connection of the overlapping side edges represents a thickening of the material of the first elastomer layer. In contrast to the prior art, however, this thickening no longer runs axially along the longitudinal axis of the bellows blank, but in a coaxial spiral shape around the longitudinal axis. As a result, the material thickening is distributed much better in the circumferential direction and reduces the local stiffening of the later bellows product.

According to a preferred embodiment, the thread layer is cut to size in the form of a rectangle and deposited on the conveying device in such a way that its threads are aligned parallel to the longitudinal axis of the winding mandrel. This alignment of the threads results in a later bellows product with axially aligned threads.

According to a further preferred embodiment, the bellows blank is wound together from an additional second elastomer layer, the second elastomer layer being cut to size in the form of a parallelogram and deposited on the conveyor device in such a way that two side lengths of the second elastomer layer are aligned obliquely to the longitudinal axis of the winding mandrel.

The second elastomer layer is cut obliquely from a supply roll in the same way that a parallelogram shape results. As with the first elastomer layer, the parallelogram-shaped arrangement of the second elastomer layer results in a coaxially spiral-shaped overlap of the adhesive side edges of the second elastomer layer. This also contributes to a better distributed thickening of the material of the entire bellows blank and thus reduces the locally occurring stiffness of the later bellows product.

The two inclined side lengths run at an angle between 1 ° and 89 ° with respect to the longitudinal axis of the winding mandrel. The two side lengths of the second elastomer layer are preferably oriented opposite to the two side lengths of the first elastomer layer. That is, the second elastomer layer is placed on the conveyor device in a different orientation than the first elastomer layer. This results in an overlap of the second elastomer layer on the bellows blank, which runs in a different direction than the overlap of the first elastomer layer. This contributes to a more even distribution of the thickened material of the bellows product.

The first elastomer layer is preferably produced from a multiplicity of sub-layers. These sub-layers are deposited on the conveyor at the same angle, but with a small offset to one another. Alternatively, the partial layers have angles that differ from one another. These measures serve to optimize the helical overlap of the first elastomer layer. The relative thickening of the first elastomer layer at the point of overlap decreases compared to a single thick elastomer layer, so that the stiffening effect is reduced. The local distribution of a thickened overlap no longer runs individually along a strand of thread, but in a distributed manner across several strands of thread. This has the advantage that the stiffening effect is better distributed over the height of the bellows product and the pressure of the bellows material into the spaces between the threads is reduced.

This effect can additionally be reduced in that, when using a single thread layer with sufficient strength, the wall thickness of the first elastomer layer is selected to be thick-walled so that the stiffening effect is further reduced. Such a thickened first elastomer layer is able to distribute the internal pressure more evenly on the threads of the thread layer without the risk of the elastomer material being pressed into the spaces between the threads.

A bellows blank is produced or wound up by the method described, which is then fed to an expansion and vulcanization process in order to produce the finished bellows product for an air spring of a motor vehicle.

Consequently, a further aspect of the invention is to provide an air spring for a motor vehicle, which comprises two connecting parts, between which at least one thread-reinforced bellows made of elastomeric material is clamped in a pressure-tight manner, the bellows being formed from at least one first elastomer layer and one thread layer, two of which are in Adhesive connection located side lengths of the first elastomer layer overlap in such a way that an overlap of these side lengths runs in a coaxial spiral shape around a longitudinal axis of the air spring.

The air spring according to the invention has the advantage that the thread-reinforced bellows does not have a longitudinal thickening of bellows material, but rather the coaxially running overlap, which runs from the lower end of the bellows spirally along its circumference to the upper end of the bellows. This has the main effect that an axially extending thickening with a locally high rigidity is avoided. This reduces the risk of the bellows material being pressed into the spaces between the threads of the thread layer at adjacent points of lower strength, as a result of which the bursting pressure property of the bellows is significantly improved.

The overlap of the first elastomer layer results from their mutually facing side lines, which are superposed in an adhesive manner, so that these side lines are to be understood as side edges and thus create a bellows wall that is closed in the circumferential direction.

According to a preferred embodiment, two side lengths of the thread layer overlap axially along the longitudinal axis of the air spring. The thread layer is aligned with its threads parallel to the longitudinal axis of the air spring, so that an axial bellows is present. This axial alignment of the threads takes place by a corresponding laying down of the thread layer when the bellows blank is produced, an overlap of the facing side lines of this thread layer being produced in order to ensure a closed thread layer.

According to a further preferred embodiment, the bellows is formed from an additional second elastomer layer, with two side lengths of the second elastomer layer that are in adhesive connection overlapping such that an overlap of these side lengths runs in a coaxial spiral shape around the longitudinal axis of the air spring.

The overlap of the second elastomer layer is created in the same way as the overlap of the first elastomer layer in that the side lines facing each other are superimposed as side edges, which creates a closed bellows wall. As with the first elastomer layer, the second elastomer layer with its spiral-shaped overlap reduces the stiffening of the bellows material at one point. Rather, the thickening of the bellows material is distributed much better in the circumferential direction due to the spiral shape, so that local stiffnesses are alleviated. In particular, with two elastomer layers, the axially extending thickenings from the prior art can no longer easily add up at one point. A more uniform distribution of the thickened areas of the overlaps of the first and second elastomer layers is preferably supported by the fact that the overlap of the second elastomer layer runs opposite to the overlap of the first elastomer layer.

If the air spring according to the invention is combined with an integrated shock absorber, it is an air spring strut in which the air spring with bellows according to the example is also used.

The air spring is used in a chassis of a motor vehicle, in particular in an air spring system.

Further preferred embodiments of the invention emerge from the dependent claims and the following description of an embodiment with reference to the figures.

• 1 ein beispielsgemäßes Verfahren zur Herstellung eines Balgrohlings,
• 2 die Zwischenstufen des aufgewickelten Balgrohlings, und
• 3 eine beispielsgemäße Luftfeder.

Show it

• 1 an exemplary method for producing a bellows blank,
• 2 the intermediate stages of the wrapped bellows blank, and
• 3 an exemplary air spring.

The 1 shows schematically an exemplary method for producing a bellows blank.

On a changing table 1 are several cut layers 3 , 4th and 5 stored, which are to be wound into a bellows blank. The locations 3 , 4th and 5 are in one conveying direction 10 a rotating cylindrical mandrel 2 fed, which with its longitudinal axis L. perpendicular to the long side of the changing table 1 is aligned. The direction of rotation of the winding mandrel 2 is with the arrow at the reference symbol 9 illustrated.

First off a first elastomer supply roll 6 a first unvulcanized vulcanizable elastomer layer 3 cut off. Here is the first elastomer layer 3 Cut off at an angle of, for example, 45 °, so that the first elastomer layer has a parallelogram shape 3 results. Thereupon the first elastomer layer becomes 3 so on changing table 1 filed that their cut sides b and d perpendicular to the longitudinal axis L. of the winding mandrel 2 are aligned, while the other two side lengths are a and c at an angle, for example 45 °, to the longitudinal axis L. of the winding mandrel 2 aligned.

Next is from a thread supply roll 7th a thread layer 4th cut off and with a certain offset to the first elastomer layer 3 on changing table 1 filed. Thread layer 4th is cut in a rectangular shape and becomes its long side a '' parallel to the longitudinal axis L. of the winding mandrel 2 on changing table 1 filed. The short side b '' the thread layer 4th is consequently at an angle of 90 ° to the longitudinal axis L. of the winding mandrel 2 aligned. With thread position 4th a large number of threads are applied to a carrier film. In this way, all threads are essentially parallel to one another and also parallel to the longitudinal axis L. of the winding mandrel 2 aligned. This results in an axial alignment of the thread layer in the bellows product wound up later 4th .

Last is from a second elastomer supply roll 8th a second uncured vulcanizable elastomer layer 5 cut off and also with a small offset to the thread layer 4th on changing table 1 filed. Second elastomer layer 5 is also like the first elastomer layer 3 cut in the form of a parallelogram and placed on a changing table 1 filed. Consequently, the cut sides lie b ' and d ' at a right angle on the changing table 1 and the side lengths a ' and c ' run at a certain angle, e.g. B. 45, to the longitudinal axis L. of the winding mandrel 2 . The alignment of the second elastomer layer 5 takes place in the opposite direction to the first elastomer layer 3 .

After the layers 3 , 4th and 5 have been stored in the manner according to the example, these will be around its longitudinal axis L. rotating mandrel 2 fed so that they are on the winding mandrel 2 can be wound up into an unvulcanized blank bellows.

With the 2a , 2 B and 2c illustrates how the individual wound layers are 3 , 4th and 5 on the mandrel 2 represent.

In the 2a became the first elastomer layer 3 with their cut sides in the circumferential direction on the winding mandrel 2 wound up. As the first elastomer layer 3 was cut with a certain strip width, the winding of the elastomer material creates an adhesive overlap 11 the facing side lengths of the first elastomer layer 3 . The overlapping side lengths result from the in 1 side lengths shown a and c the first elastomer layer 3 . As a result, the first elastomer layer 3 was stored as a parallelogram, the side lengths running at an angle form the spiral overlap 11 the first elastomer layer 3 . The visible side length of the first elastomer layer 3 is shown with the continuous line and the overlapped side line of the first elastomer layer 3 is highlighted with a dashed line. Consequently extends along the longitudinal axis L. of the winding mandrel 2 a coaxial spiral overlap 11 over the entire length of the first elastomer layer 3 .

After the first elastomer layer 3 The thread layer follows 4th in the 2 B . Because the thread layer 4th was placed in a rectangular shape, it is parallel to the longitudinal axis L. of the winding mandrel 2 running overlap 12 on. Here, too, the visible sideline is the thread layer 4th with the continuous line and the hidden side line is shown in dashed lines.

Finally the second elastomer layer 5 wound, with also a spiral overlap 13 which, however, runs in a different direction than the overlap 11 the first elastomer layer 3 . The coaxial spiral overlap 13 is done in the same way as the overlap 11 the first elastomer layer 3 generated. There second elastomer layer 5 also aligned as a parallelogram, arises from the side lengths a ' and c ' , which in the 1 were shown, the spiral around the longitudinal axis L. of the winding mandrel 2 running overlap. The solid line in the 2c illustrates the visible side line and the dashed line the hidden side line of the second elastomer layer 5 .

After all locations 3 , 4th and 5 have been wound up, the unvulcanized bellows blank can be removed from the winding mandrel 2 are removed and fed to the expansion and vulcanization process in order to produce the finished bellows product for the air spring of a motor vehicle.

With the 3 is an exemplary air spring 20th shown, which represents in the left view from the outside and with the right view the air spring 20th shows in section.

Exemplary air spring 20th comprises a cover as a first connection part 21st for connection to the vehicle body and a rolling piston as a second connection part 22nd for connection to a wheel carrier. This regular installation position of the air spring 20th determines the "top / bottom" orientation. The longitudinal axis of the air spring 20th is with L _F marked.

On the lid 21st is a tubular bellows 23 made of elastomeric material with a thread reinforcement connected pressure-tight through its upper end. The upper end of the bellows is attached using a clamping ring 25th on the fastening shaft of the lid 21st . The threads of the bellows 23 run parallel to the longitudinal axis L _F the air spring 20th so that this acts as an axial bellows 23 referred to as.

A separate elastomer bellows that functions as a thread-reinforced roll bellows 24 is with its lower end on the rolling piston 22nd connected pressure-tight. Here, too, the lower end of the bellows is attached using a further clamping ring 25th on the attachment shaft of the rolling piston 22nd . The thread reinforcement of the bellows 24 provides intersecting threads, so that this acts as a cross-ply bellows 24 referred to as.

Furthermore, cross-ply bellows 24 at least partially from a sleeve-shaped outer guide 26th enclosed and rolls with the formation of a roll fold 31 on a contour shell 28 of the rolling piston 22nd from. External guide 26th is used as a support corset to cope with the high pressure inside the air spring 20th to counteract.

In the example of the air spring 20th become axial bellows 23 and cross-ply bellows 24 connected in an overlapping manner. There is a clamping ring for this 27 and the upper area of the outer guide 26th intended. The lower end of the axial bellows 23 overlaps the top of the cross-ply bellows 24 on the outside and in the circumferential direction so that the ends of both bellows 23 , 24 by means of a clamping ring 27 against the inside of the outer guide 26th be pressed.

The fact that axial bellows 23 on the lid 21st and cross-ply bellows 24 on the rolling piston 22nd are attached and by means of external guides 26th and clamping ring 27 in a central area of the air spring 20th are jointly connected in a pressure-tight manner, is a common pressure space 36 limited. This can be filled with compressed air and, as a volume-elastic space, acts as a spring.

So that air spring 20th Axial bellows is used to compensate for lateral forces 23 designed as a cardanic fold. In order for the folds necessary for the deflection movement to be generated, in a central area of the axial bellows 23 a taming ring 29 from the outside onto the axial bellows 23 created. Taming ring 29 laces axial bellows 23 such that it is directly above and below the ring 29 form two folds, namely a first cardanic fold 32 towards the lid 21st and a second gimbal fold 33 towards the exterior 26th . With that taming ring 29 cannot be moved axially, is in the pressure chamber 36 a counter holder 30th on axial bellows 23 put on what taming ring 29 holds in axial position.

Axial bellows 23 is composed of at least two elastomer layers and one thread layer, the thread layer being arranged between the two elastomer layers. According to the example, the inner elastomer layer has been wound up by means of the manufacturing process described above in such a way that two mutually facing side lines or also side edges overlap in an adhesive manner in such a way that a coaxially spiraling overlap 34 present. This overlap 34 so runs around the longitudinal axis L _F the air spring 20th along the inner circumference and over the entire height of the axial bellows 23 . Right view of the 3 is this overlap 34 The dotted line shows the visible side line of the inner layer, while the dotted line indicates the hidden side line.

Left view of the 3 is an overlap 35 to be taken from the outer layer. The dashed line represents the visible side line of the outer elastomer layer and the dotted line represents the hidden side line of this elastomer layer. It can be seen that the overlap 35 coaxially in a spiral shape around the longitudinal axis L _F the air spring 20th runs around. This overlap 35 the outer layer is made in the same way as the overlap 34 of the inner layer produced by the two mutually facing side lines of the outer layer superimposed in an adhesive manner. Thus there is an overlap 35 on the outer circumference of the axial bellows 23 in a spiral shape over its entire height.

This kind of spiral overlap 34 and 35 it is ensured that there is no point on the axial bellows 23 there is a material overlap axially along the longitudinal axis L _F the air spring 20th extends. Partial thickening in the circumferential direction is thus advantageously avoided.

List of reference symbols

1

Changing table

2

Winding mandrel

3

first elastomer layer

4th

Thread layer

5

second elastomer layer

6th

first elastomer supply roll

7th

Thread supply roll

8th

second elastomer supply roll

9

Direction of rotation

10

Conveying direction

11

Overlap of the first elastomer layer

12

Overlap of the thread layer

13

Overlap of the second elastomer layer

20th

Air spring

21st

cover

22nd

Rolling piston

23

Bellows / axial bellows

24

Roll bellows / cross-ply bellows

25th

Clamping rings

26th

External guide

27

Tension ring

28

Contour shell

29

Taming ring

30th

Counterholder

31

Roll fold

32

first cardanic fold

33

second gimbal fold

34

Overlap first elastomer layer

35

Overlap second elastomer layer

36

Printing room

a, b, c, d

Side lengths of the first elastomer layer

a ', b', c ', d'

Side lengths of the second elastomer layer

a '', b ''

Side lengths of the thread layer

L.

Longitudinal winding mandrel

L _F

Longitudinal axis air spring

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 3794538 A [0003]

Claims (10)

Method for producing a bellows blank for an air spring (20), the bellows blank being wound together from at least a first elastomer layer (3) and a thread layer (4), a conveyor device (1) transferring the layers (3; 4) to a rotating winding mandrel ( 2) for winding up and the winding mandrel (2) is arranged with its longitudinal axis (L) essentially at right angles to a conveying direction (10) of the conveying device (1), characterized in that the first elastomer layer (3) is cut in the form of a parallelogram and is deposited on the conveyor (1) in such a way that two side lengths (a; c) of the first elastomer layer (3) are aligned obliquely to the longitudinal axis (L) of the winding mandrel (2). Procedure according to Claim 1 , characterized in that the thread layer (4) is cut in the shape of a rectangle and deposited on the conveyor (1) in such a way that its threads are aligned parallel to the longitudinal axis (L) of the winding mandrel (2). Procedure according to Claim 1 or 2 , characterized in that the bellows blank is wound together from an additional second elastomer layer (5), the second elastomer layer (5) being cut to size in the form of a parallelogram and placed on the conveyor device (1) in such a way that two side lengths (a ';c' ) the second elastomer layer (5) are aligned obliquely to the longitudinal axis (L) of the winding mandrel (2). Procedure according to Claim 3 , characterized in that the two side lengths (a ';c') of the second elastomer layer (5) are aligned opposite to the two side lengths (a; c) of the first elastomer layer (3). Bellows blank produced by a method according to one of the Claims 1 to 4th . Air spring (20) for a motor vehicle, comprising two connecting parts (21; 22) between which at least one thread-reinforced bellows (23) made of elastomeric material is clamped in a pressure-tight manner, the bellows (23) made of at least one first elastomer layer (3) and one thread layer ( 4), characterized in that two side lengths (a; c) of the first elastomer layer (3) which are in adhesive connection overlap in such a way that an overlap (34) of these side lengths (a; c) in a coaxial spiral shape around a longitudinal axis ( L _F ) of the air spring (20) runs. Air spring (20) Claim 6 , characterized in that two side lengths (a ″) of the thread layer (4) overlap axially along the longitudinal axis (L _F ) of the air spring (20). Air spring (20) Claim 6 or 7th , characterized in that the bellows (23) is formed from an additional second elastomer layer (5), wherein two side lengths (a ';c') of the second elastomer layer (5) that are in adhesive connection overlap in such a way that an overlap (35) these side lengths (a ';c') runs in a coaxial spiral shape around the longitudinal axis (L _F ) of the air spring (20). Air spring after Claim 8 , characterized in that the overlap (35) of the second elastomer layer (5) runs opposite to the overlap (34) of the second elastomer layer (3). Motor vehicle comprising an air spring (20) according to one of the Claims 6 to 9 .

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