AIR SPRING AND METHOD FOR ITS MANUFACTURING

Description

[0001] The invention relates to an air spring, for example of a vehicle axle, with a tubular rolling diaphragm made of an elastomeric material, which has at least one beadless and coreless end section, wherein this end section is attached by means of an adhesive to a largely cylindrical seating surface of a connecting part. The invention also relates to a method for manufacturing such an air spring.

[0002] In an air spring, the attachment of a rolling diaphragm to a connecting part of an air spring cap or a rolling piston is typically achieved via a clamping connection. In this connection, the relevant end section of the rolling diaphragm, after being slid onto a largely cylindrical outer seating surface of the associated connecting part, is radially clamped by a band-shaped clamping ring, thereby creating a pressure-tight seal. The clamping ring, usually made of sheet steel or wire, is shortened circumferentially by plastic deformation using a suitable tool after being placed on the end section of the rolling diaphragm. This reduces the radius of the clamping ring, causing the end section of the rolling diaphragm to be pressed radially against the seating surface of the connecting part.

[0003] Such a clamping connection is critical because manufacturing tolerances in the diameter of the connecting part's seat wall, the thickness and diameter of the rolling diaphragm, and the diameter of the clamping ring all add up. Furthermore, the connecting part, manufactured as an injection-molded component from a thermoplastic, and the clamping ring have different coefficients of thermal expansion. This leads to loosening of the clamping connection during cooling, as the diameter of the outer metallic clamping ring shrinks less than the clamping diameter of the plastic connecting part.

[0004] Furthermore, significant temperature fluctuations can cause settling and flow processes in the bellows and the connecting part in the area of ​​the clamping connection, which can also lead to loosening of the clamping connection. All of this can result in compressed air escaping from the interior of the air spring and, in extreme cases, the bellows slipping off the connecting part. Therefore, precise assembly of the components involved in the clamping connection, as well as accurate control of the forming of the clamping ring, is necessary to prevent leaks and slippage of the bellows from the connecting part if the components are not compressed sufficiently, and to prevent damage to the connecting part and the bellows, particularly crushing of the bellows, if the components are compressed too tightly.

[0005] To improve the sealing and slip resistance of the clamping connection of the rolling diaphragm, it is known to design the seat wall of the respective connecting part concavely and / or to profile it with circumferential ribs or grooves. The end section of the rolling diaphragm is then pressed against the concave seat wall by the clamping ring and, under elastic deformation, pressed onto the ribs and into the grooves.

[0006] US Patent 5,005,808 A describes several clamping connections between a rolling diaphragm and the connecting parts of an air spring cover and a rolling piston. In these connections, the seat walls are cylindrically flat or concave and each has at least two circumferential grooves with a pointed or rounded profile. The clamping rings, on the other hand, are cylindrically flat with rounded edges. When assembled, the end sections of the rolling diaphragm are elastically pressed into the curvature and grooves of the seat wall by radial tension. However, this increases the manufacturing complexity of the connecting parts.

[0007] In one embodiment of a clamping connection according to DE 100 50 777 B4, the seat wall of the connecting part has two circumferential grooves at its edges, which are rounded or taper towards the center and result in a convexly rounded or gable-shaped profile of the seat wall. The clamping ring is correspondingly convexly rounded or angled in the center, so that the relevant end section of the bellows is elastically pressed into the grooves of the seat wall by the clamping ring when assembled. Manufacturing costs are increased for these clamping connections because, in addition to the seat walls of the connecting parts, the clamping rings are also profiled.

[0008] Another known measure for improving the sealing of a rolling diaphragm against a connecting part consists of arranging at least one annular sealing element between the seat wall of the connecting part and the end section of the rolling diaphragm. For example, DE 197 40 981 A1 discloses two clamping connections, in which, in a second embodiment, a sealing element formed from an elastomer strip is arranged between the seat wall of the connecting part, which is provided with small circumferential grooves, and the end section of the rolling diaphragm. In a fourth embodiment, a sealing element formed from a wider elastomer strip is folded around the end section of the rolling diaphragm at its free end and is thus arranged both between the seat wall of the connecting part and the end section of the rolling diaphragm, and between the end section of the rolling diaphragm and the clamping ring.The outer arrangement of the elastomer strip is intended to prevent damage to the rolling bellows by the tension ring.

[0009] Using separate sealing elements increases assembly effort and carries the risk that the sealing element will slip on the connection piece when the bellows is extended, thus ending up in a position other than its intended position. If grooves are provided in the respective seating surface, the manufacturing effort for this type of clamping connection is also increased. Another way to improve the seal between a bellows and a connection piece is to integrally mold at least one ring-shaped sealing element onto the bellows during its manufacture.

[0010] In one embodiment of such a clamping connection according to DE 10 2006 033 197 A1, two circumferential sealing lips are formed on an end section of a rolling diaphragm on the side facing the seat wall of the connecting part, which are pressed against the cylindrically flat seat wall of the connecting part in the assembled state.

[0011] In one embodiment of such a clamping connection according to DE 10 2010 036 363 A1, a circumferential sealing ring with a circular cross-section is integrally formed on the end section of a rolling diaphragm on the side facing the seat wall of the connecting part. This sealing ring is connected to the wall of the rolling diaphragm via a circumferential web. In the assembled state, the sealing ring is pressed by the cylindrically flat clamping ring into a circumferential groove with a rectangular cross-section located in the seat wall, under elastic deformation.

[0012] The use of molded sealing elements increases the manufacturing effort for the bellows. Furthermore, there is a risk that the sealing elements will be damaged or even sheared off when the bellows is extended onto its corresponding connecting piece. If at least one groove is provided in the respective seating surface, the manufacturing effort for the connecting piece is also increased.

[0013] Finally, a suitable adhesive or sealant can also be used for sealing in a clamping connection between a rolling diaphragm and a connecting piece. A corresponding clamping connection, in which an adhesive is applied to the seating surface of the connecting piece or the relevant section of the rolling diaphragm before the rolling diaphragm is pushed onto the connecting piece, is known from DE 10 2008 025 905 A1. In the clamping connections described therein, the adhesive is applied over the entire surface of the seating surface of the connecting piece or the relevant section of the rolling diaphragm. At low pressures, the rolling diaphragm should be held to the connecting piece solely by the adhesive.In another embodiment of this clamping connection, the adhesive is introduced into an annular groove or into several annular grooves arranged in the seat surface, and the end section is pressed against the seat surface by means of an additionally required band-shaped clamping ring in applications with not insignificant pressures and is thereby fixed to the connecting part.

[0014] In a similar clamping connection according to DE 10 2016 219 813 A1, during assembly, after sliding a rolling diaphragm onto a connecting part and clamping it radially with a clamping ring, a permanently viscous sealant is introduced into an annular gap between the connecting part and the rolling diaphragm. The use of an adhesive or sealant to seal the clamping connection increases the assembly effort accordingly.

[0015] Document DE 10 2008 025905 A1, which is considered to be the closest prior art, discloses the features of the preamble of claim 1.

[0016] In the aforementioned designs of clamp connections of a rolling diaphragm to a connecting part, the problems that the clamp connections can loosen and leak due to the different coefficients of thermal expansion of the connecting part and the clamping ring, as well as due to settling and flow processes of the material of the rolling diaphragm and the connecting part, are either not solved or only solved with high manufacturing and / or assembly effort.

[0017] The invention was therefore based on the objective of presenting an air spring of the aforementioned design, in which at least one beadless and coreless end section of a rolling diaphragm is mechanically reliably and pressure-tightly attached to a connecting part of an air spring cover or a rolling piston in a simple and cost-effective manner. Furthermore, a method for manufacturing such an air spring was to be described.

[0018] The product-related problem is solved by an air spring with the features of claim 1. An independent method claim specifies a method for manufacturing such an air spring. Advantageous embodiments are defined in the associated dependent claims.

[0019] Accordingly, the invention relates to an air spring, for example of a vehicle axle, with a tubular rolling diaphragm made of an elastomeric material, which has at least one beadless and coreless end section, wherein this end section is attached by means of an adhesive to a largely cylindrical seating surface of a connecting part. The connecting part is cup-shaped on its side facing the rolling diaphragm and has a side wall with a cylindrical inner surface and a bottom wall, and the end section of the rolling diaphragm is attached to the inner surface of the side wall, which acts as a seating surface, by means of the adhesive without a clamping ring.

[0020] In order to attach at least one bulge- and coreless end section of a rolling diaphragm to a connecting part of an air spring cover or a rolling piston in a simple, cost-effective, mechanically reliable, and pressure-tight manner, the connecting part in question is designed to be cup-shaped on the side facing the rolling diaphragm. It has a circular side wall with a cylindrical inner surface and a bottom wall that is at least largely flat. The associated end section of the rolling diaphragm is attached to the inner surface of the connecting part's side wall, which acts as a seat, solely by means of adhesive, without the need for a clamping ring or clamping ring.

[0021] By eliminating the clamping ring, the problem of differing coefficients of thermal expansion between the connecting piece and the clamping ring is eliminated, and the assembly of the bellows to the connecting piece is simplified. Due to the simple geometry of the connecting piece and the seating surface formed on the side wall, the adhesive bond is easy and cost-effective to create. Using a suitable adhesive, the connection between the bellows and the connecting piece is mechanically reliable and pressure-tight. The bonding therefore occurs primarily between the outer surface of the bellows and the inner surface of the connecting piece's side wall, meaning that during operation of the bellows, the bonded area is subjected to shear stress rather than harmful peeling stress.

[0022] Since the rolling bellows, made of an elastomer material, naturally exhibits relatively large tolerances in its diameter and wall thickness, its optimal bonding to a precisely manufactured metallic connecting part presents considerable challenges. The goal is to achieve full-surface contact between the end section of the rolling bellows and the seating surface of the connecting part.

[0023] To achieve the best possible adhesive bond, the invention provides that the axial end section of the rolling diaphragm is radially compressed around its circumference in the area of ​​the side wall of the connecting part. This mechanical deformation eliminates manufacturing-related dimensional tolerances of the rolling diaphragm, resulting in the rolling diaphragm lying flush against the seating surface of the side wall of the connecting part over its entire circumference. This ensures optimal adhesion. The radial contact force required for an optimal adhesive bond is applied by the radially outward-directed counterforce that acts in response to the radially inward compression of the rolling diaphragm and the resulting residual stress. Therefore, the arrangement and activation of a separate clamping ring, as in prior art, is unnecessary.

[0024] It is stipulated that the outer diameter D B_a of the rolling diaphragm in the area of ​​the end section, in the radially unstrained state, taking into account the most unfavorable component tolerances and thermal expansion, is larger than the diameter D S_i of the seating surface of the connecting part (D B_a > D S_i). This ensures that the compression of the end section of the rolling diaphragm, and thus the radial tension of the rolling diaphragm with the connecting part, is maintained under all operating conditions.

[0025] For the compression of the end section of the rolling diaphragm during axial insertion into the connecting part, it can be provided that the side wall of the connecting part has an axially outer mounting section with a conical inner surface, wherein the axial inner diameter D K_i of the conical inner surface corresponds to the diameter D S_i of the seat surface (D K_i = D S_i ), and the axial outer diameter D K_a of the conical inner surface, taking into account the most unfavorable component tolerances and thermal expansions, is larger than the outer diameter D B_a of the rolling diaphragm in the area of ​​the end section (D K_a > D B_a ).

[0026] Alternatively, it can be provided that, for the radial compression of the end section of the rolling bellows, the axial outer edge of the side wall of the connecting part is designed such that an assembly tool with a cylindrical ring body and a radially internally conical inner surface can be placed on it, wherein the conical inner surface has an axial inner diameter D K_i, which corresponds to the diameter D S_i of the seat surface (D K_i = D S_i ), and whose axial outer diameter D K_a, taking into account the most unfavorable component tolerances and thermal expansions, is larger than the outer diameter D B_a of the rolling bellows in the area of ​​the end section (D K_a > D B_a ).

[0027] To prevent the adhesive from being rubbed off, the seating surface of the connector is axially limited on the outside, for example, by a circumferential bead. Such a bead is preferably used when a thicker adhesive layer is employed.

[0028] For the exact and wrinkle-free positioning of the outer edge of the bellows on the inner edge of the seat surface and on the bottom wall, it is preferably provided that at least one annular seat rib is arranged on the bottom wall of the connecting part, the radial distance ΔRs, ΔRs' of which from the seat surface largely corresponds to the sum of the thickness d B of the end section of the bellows and the thickness d K , d K ' of the adhesive layer (ΔRs ≈ d B + d K ; ΔR S ' ≈ d B + d K ').

[0029] To prevent the formation of creases during axial insertion of the rolling diaphragm into the connecting part when the end section of the rolling diaphragm is compressed against the conical inner surface of the connecting part or the assembly tool, several radial guide ribs may be arranged uniformly around the circumference of the bottom wall and the seating rib of the connecting part. The respective radial outer surface of each guide rib is conically chamfered and inclined radially inwards at an angle of 1° to 35°, preferably 10° to 20°, relative to the radial outer surface of the at least one seating rib. These angle specifications include the aforementioned range limits.

[0030] As mentioned, the invention also relates to a method for manufacturing the described air spring, in which a beadless and coreless end section of a tubular rolling bellows is attached to a largely cylindrical seating surface of a connecting part by means of an adhesive, comprising the following process steps: a) Applying the adhesive to a cylindrical inner surface of a side wall of the connection part, which is cup-shaped on the side facing the bellows and acts as a seat, b) circumferential and radial compression of the end section of the bellows, and c) axial insertion of the bellows into the connection part with the end section of the bellows onto the seat surface of the connection part.

[0031] The radial inward compression of the end section of the rolling bellows creates internal stress, which generates a radially outward counterforce. This counterforce ensures that the end section of the rolling bellows is pressed against the adhesive on the seating surface of the connecting part across its entire surface, resulting in a very strong adhesive bond.

[0032] According to a first method variant, it is provided that the end section of the rolling bellows is radially compressed inwards by axial insertion into the connecting part at an outer mounting section of the side wall of the connecting part with a conical inner surface, whose axial inner diameter D K_i corresponds to the diameter D S_i of the seat surface (D K_i = D S_i ), and whose axial outer diameter D K_a, taking into account the most unfavorable component tolerances and thermal expansions, is larger than the outer diameter D B_a of the rolling bellows in the area of ​​the end section (D K_a > D B_a ).

[0033] An alternative second method variant provides that the end section of the rolling bellows is radially compressed inwards by axial insertion into an assembly tool with a cylindrical ring body and a conical inner surface, the axial inner diameter D K_i of which corresponds to the diameter D S_i of the seat surface (D K_i = D S_i ), and the axial outer diameter D K_a of which, taking into account the most unfavorable component tolerances and thermal expansions, is larger than the outer diameter D B_a of the rolling bellows in the area of ​​the end section (D K_a > D B_a ).

[0034] To further illustrate the invention, a drawing with three exemplary embodiments is attached to the description. This drawing shows Fig. 1 a first embodiment of an air spring according to the invention before assembly in a partial cross-sectional view, Fig. 2the connection part of the air spring according to Fig. 1 in a partial axial view, Fig. 3 the air spring according to Fig. 1 and Fig. 2 in the assembled state in a partial cross-sectional view, Fig. 4 a second embodiment of an air spring according to the invention before assembly in a partial cross-sectional view, and Fig. 5 a third embodiment of an air spring according to the invention in the assembled state in a partial cross-sectional view.

[0035] According to the in Fig. 1 The first embodiment of an air spring 1 according to the invention, as shown, has a tubular rolling diaphragm 2 with a beadless and coreless axial end section 4 and a connecting part 6 of an air spring cover or a rolling piston. These components 4, 6 are in Fig. 1 before their assembly and in Fig. 3 Shown in its assembled state. Fig. 2The connecting part 6 is shown in a partial axial view from the viewing direction BB according to Fig. 1 depicted.

[0036] The connecting part 6 is cup-shaped on its axial side facing the rolling bellows 2 and has a side wall 8 with a cylindrical inner surface 10 and a largely flat bottom wall 12. In the assembled state according to Fig. 3 The end section 4 of the rolling bellows 2 is attached without a tension ring by means of an applied adhesive 24 to the inner surface 10 of the side wall 8, which acts as a seat surface.

[0037] To ensure that the end section 4 of the rolling bellows 2 has a constant outer diameter in its connection position, among other things for an optimal adhesive bond, it is guided during its axial insertion into the connecting part 6 according to the Figure 1 and 3 or the Figures 4 and 5The bellows 2 is compressed radially inwards over its entire circumference. As a side effect of this radial inward compression, the bellows 2 generates a radially outward force to harmonize its outer diameter, pressing it against the seating surface 10 of the side wall 8 of the connecting part 6. This ensures optimal contact between the bellows wall and the seating surface 10 of the side wall 8 of the connecting part 6 during the curing of the adhesive bond, even without a radially inward to radially outward force acting on the bellows 2 from a clamping ring or clamping ring.

[0038] It is provided that the outer diameter D B_a of the rolling bellows 2 in the area of ​​the end section 4 in the uncompressed state, taking into account the most unfavorable component tolerances and thermal expansions, is larger than the diameter D S_i of the seat surface 10 of the connecting part 6 (D B_a > D S_i ).

[0039] For generating the compression of the end section 4 of the rolling bellows 2, the side wall 8 of the connecting part 6 has an axially outer mounting section 14 with a conical inner surface 16, whose axial inner diameter D K_i corresponds to the diameter D S_i of the seat surface 10 (D K_i = D S_i ), and whose axial outer diameter D K_a, taking into account the most unfavorable component tolerances and thermal expansions, is larger than the outer diameter D B_a of the rolling bellows 2 in the area of ​​the end section 4 (D K_a > D B_a ).

[0040] For the exact and wrinkle-free positioning of the outer edge of the bellows 2 on the inner edge of the seat surface 10 and on the bottom wall 12, an annular seat rib 18 is arranged or formed on the bottom wall 12 of the connecting part 6, the radial distance ΔRs from the seat surface 10 largely corresponds to the sum of the thickness d B of the end section 4 of the bellows 2 and the thickness d K of the adhesive layer 24 (ΔRs ≈ d B + d K ).

[0041] To prevent the formation of creases during axial insertion of the rolling diaphragm 2 into the connecting part 6 when the end section 4 of the rolling diaphragm 2 is compressed on the conical inner surface 16 of the assembly section 14, several radial guide ribs 20 are arranged circumferentially and evenly distributed on the bottom wall 12 and the seating rib 18 of the connecting part 6. The respective radial outer surface 22 of each guide rib is conically chamfered and inclined radially inwards at an angle of 10° to 20° relative to the radial outer surface of the at least one seating rib 18. In this example, a total of twelve guide ribs 20 are provided, arranged circumferentially offset by 30° on the bottom wall 12 and the seating rib 18 of the connecting part 6.

[0042] According to a second embodiment of the air spring according to the invention, in Fig. 4A partial cross-sectional view shows a beadless and coreless end section 4 of a tubular rolling bellows 2 and a connecting part 6' of an air spring cover or a rolling piston before assembly. This air spring differs from the air spring according to the Figures 1 to 3by using a mounting tool 26 with a cylindrical ring body 28 and a conical inner surface 30, which can be placed on the axial outer edge of the side wall 8' of the connecting part 6', instead of the mounting section 14 with the conical inner surface 16 for compressing the end section 4 of the rolling diaphragm 2. The axial inner diameter DKi of the conical inner surface 30 corresponds to the diameter DS_i of the seat surface (DK_i = DS_i), and the axial outer diameter DK_a of the conical inner surface 30 is larger than the outer diameter DB_a of the rolling diaphragm 2 in the region of the end section 4 of the rolling diaphragm 2 (DK_a > DB_a), taking into account the most unfavorable component tolerances and thermal expansions.

[0043] Fig. 5Figure 1 shows a partial cross-sectional view of a third embodiment of the air spring according to the invention in the assembled state, which also has a tubular rolling bellows 2 with a beadless and coreless end section 4 and a connecting part 6" of an air spring cover or a rolling piston.

[0044] This air spring differs from the air springs according to the Figures 1 to 3 by applying a thicker layer of adhesive 24' to the seating surface 10 of the side wall 8", and by limiting the seating surface 10 of the connecting part 6" axially on the outside by a circumferential bead 32 projecting radially inwards to protect against the adhesive 24' being rubbed off.

[0045] In all three embodiments of the air spring 1, the end section 4 of the rolling bellows 2 is bonded to the seating surface 10 of the connecting part 6, 6', 6" without a clamping ring, solely by means of the adhesive 24, 24'. Due to the simple geometry of the connecting part 6, 6', 6" and the seating surface 10 formed on the side wall 8, 8', 8", this adhesive bond is easy and inexpensive to produce and, when a suitable adhesive 24, 24' is used, forms a mechanically reliable and pressure-tight connection between the rolling bellows 2 and the connecting part 6, 6', 6". Reference symbol list

[0046] 1 Air spring 2 Rolling bellows 4 End section 6, 6', 6" Connection part 8, 8', 8" Side wall 10 Inner surface, seat surface 12 Bottom wall 14 Mounting section 16 Inner surface 18 Seat web 20 Guide web 22 Outer surface 24, 24' Adhesive, adhesive layer 26 Mounting tool 28 Ring body 30 Inner surface 32 Bead B Viewing direction d B Thickness of the end section of the rolling bellows D B_a Outer diameter of the end section of the rolling bellows d K , d K 'Thickness of the adhesive or adhesive layer D K_a Axial outer diameter of the inner surface 16 or 30 D K_i Axial inner diameter of the inner surface 16 or 30 D S_i Diameter of the seat surface 10 ΔR S , ΔR S 'Radial distance

Claims

1. Air spring (1), e.g. of a vehicle axle, with a tubular rolling bellows (2) made of an elastomeric material which has at least one beadless and coreless end section (4), wherein this end section (4) is attached by means of an adhesive (24, 24') to a largely cylindrical seat surface (10) of a connecting part (6, 6', 6"), wherein the connecting part (6, 6', 6") on its side facing the rolling bellows (2) is shaped in a pot shape and a side wall (8, 8', 8") with a cylindrical inner surface (10) as well as a floor wall (12), and that the end section (4) of the rolling bellows (2) is attached to the inner surface (10) of the side wall (8, 8", 8") without a clamping ring by means of the adhesive (24, 24') which acts as a seat surface characterized in that the end section (4) of the roller bellows (2) in the area of the side wall (8, 8', 8") of the connecting part (6, 6', 6") is radially compressed over its circumference.

2. An air spring according to claim 1, characterized in that the outer diameter (DB_a) of the rolling bellows (2) in the area of the end section (4) in the radially uncompressed state, taking into account the most unfavorable component tolerances and thermal expansions, is greater than the diameter (DS_i) of the seat (10) of the connecting part (6, 6', 6") (DB_a > DS_i).

3. Air spring according to claim 1 or 2, characterized in that the side wall (8) of the connecting part (6) for the compression of the end portion (4) of the rolling bellows (2) has an axially outer mounting section (14) with a conical inner surface (16), wherein the axial inner diameter (DK_i) of the conical inner surface (16) corresponds to the diameter (DS_i) of the seat surface (10) (DK_i = DS_i), and the axial outer diameter (DK_a) of the conical inner surface (16), taking into account the most unfavourable component tolerances and thermal expansions, is greater than the outer diameter (DB_a) of the rolling bellows (2) in the area of the end section (4) (DK_a > DB_a).

4. An air spring according to any one of claims 1 to 2, characterized in that for the radial compression of the end portion (4) of the rolling bellows (2) the axial outer edge of the side wall (8') of the connecting part (6') is so formed that an assembly tool (26) with a cylindrical ring body (28) and a radial inner conical inner surface (30) can be placed on it, wherein the conical inner surface (30) has an axial inner diameter (DK_i), which corresponds to the diameter (DS_i) of the seat (10) (DK_i = DS_i), and whose axial outer diameter (DK_a) is greater than the outer diameter (DB_a) of the rolling bellows (2) in the area of the end section (4) (DK_a > DB_a), taking into account the most unfavourable component tolerances and thermal expansions.

5. Air spring according to one of claims 1 to 4, characterized in that the seat surface (10) of the side wall (8") of the connecting part (6") is axially limited externally by a circumferential bead (32) to protect against stripping of the adhesive (24').

6. An air spring according to any one of claims 1 to 5, characterized in that at least one ring-shaped seat bar (18) is arranged on the bottom wall (12) of the connecting part (6, 6', 6"), the radial distance (ΔRS, ΔRS') from the seat surface (10) is largely equal to the sum of the thickness (dB) of the end portion (4) of the rolling bellows (2) and the thickness (dK, dK') of the adhesive layer (24, 24') corresponds to ΔRS ≈ dB + dK ; ΔRS ′ ≈ dB + dK ′ .

7. Air spring according to any one of claims 1 to 6, characterized in that on the floor wall (12) and the seat bar (18) of the connecting part (6, 6', 6") several radial guide bars (20) are arranged evenly distributed on the circumferential side, the respective radial outer surface (22) is conically bevelled and radially inclined inwards at an angle of 10° to 20° in relation to the radial outer surface of at least one seat bar (18).

8. Method for the production of an air spring 1, wherein a beadless and coreless end section (4) of a tubular rolling bellows (2) is attached by means of an adhesive (24, 24') to a largely cylindrical seat surface (10) of a connecting part (6, 6', 6"), with the following process steps: a) Application of the adhesive (24, 24') to a cylindrical inner surface (10) of a side wall (8, 8', 8") of the connecting part (6, 6', 6") on the side facing the rolling bellows (2) in a pot shape, b) circumferential and radial compression of the end section (4) of the rolling bellows (2), and c) axial insertion of the rolling bellows (2) into the connecting part (6, 6', 6") with the end section (4) of the rolling bellows (2) onto the seat (10) of the connecting part (6, 6', 6").

9. A method for the manufacture of an air spring according to claim 8, characterized in that the end portion (4) of the rolling bellows (2) is radially compressed inwards by axial insertion into the connecting part (6, 6', 6") on an outer mounting portion (14) of the side wall (8) of the connecting part (6) with a conical inner surface (16), the axial inner diameter of which (DK_i) corresponds to the diameter (DS_i) of the seat surface (10) (DK_i = DS_i), and whose axial outer diameter (DK_a), taking into account the most unfavourable component tolerances and thermal expansions, is greater than the outer diameter (DB_a) of the rolling bellows (2) in the area of the end section (4) (DK_a > DB_a).

10. A method for the manufacture of an air spring according to claim 8, characterized in that the end portion (4) of the rolling bellows (2) is radially compressed inwards by axial insertion into an assembly tool (26) previously placed on the side wall (8') of the connecting part (6') with a cylindrical ring body (28) and a conical inner surface (30), the axial inner diameter of which (DK_i) corresponds to the diameter (DS_i) of the seat surface (10) (DK_i = DS_i), and whose axial outer diameter (DK_a), taking into account the most unfavourable component tolerances and thermal expansions, is greater than the outer diameter (DB_a) of the rolling bellows (2) in the area of the end section (4) (DK_a > DB_a).