Air spring with two connected bellows and method for manufacturing such an air spring

Abstract

Air spring (2) for a motor vehicle, comprising a cover (5), wherein a thread-reinforced elastomeric bellows (6) with a first bellows end (7) is attached to the cover (5), and a rolling piston (4), wherein a thread-reinforced elastomeric rolling bellows (9) with a first rolling bellows end (10) is attached to the rolling piston (4), wherein a second bellows end (8) of the bellows (6) is connected within a connection area (18) to a second rolling bellows end (11) of the rolling bellows (9), thereby defining a volume-elastic pressure chamber (12), wherein the second rolling bellows end (11) is folded outwards in the connection area (18), wherein the second bellows end (8) covers the folded second rolling bellows end (11) on the outside.wherein an inner contact surface of the folded-over second bellows end (11) is cross-linked by means of vulcanization and a contact surface of the covering second bellows end (8) with the second bellows end (11) is cross-linked by means of vulcanization and a method for manufacturing such an air spring (2).

Description

[0001] The invention relates to an air spring according to the preamble of the device claim and a method for producing such an air spring according to the independent method claim.

[0002] Air springs or air struts, which are clamped between the chassis and the body of a motor vehicle and feature a rolling bellows, which in turn is mounted between a cover and a rolling piston, are known in a variety of designs. During operation, the air spring is subjected to internal overpressure, and the rolling bellows rolls under load and during spring movements, forming a rolling fold on the outer surface of the concentric rolling piston.

[0003] A special air spring is known, for example, from DE 10 2019 209 899 A1. The air spring shown therein comprises a thread-reinforced elastomer bellows, which is attached on one side to a cover of the air spring, and a thread-reinforced elastomer rolling bellows, which is attached on the other side to a rolling piston of the air spring. The bellows and the rolling bellows are in turn connected to each other with overlapping ends using an outer guide and a clamping ring. The outer guide surrounds the rolling bellows, which, coming from the inside, is slipped over an upper end of the outer guide so that the upper end of the rolling bellows rests on the outside of the outer guide. The lower end of the bellows is placed on this end of the rolling bellows and is then surrounded by a radially adjacent clamping ring, whereby the two overlapping ends of the bellows and rolling bellows are pressed against the outer guide.Through this type of connection, the bellows and the rolling bellows define a shared, spring-elastic pressure chamber. Folding the upper end of the rolling bellows around the upper end of the outer guide has the advantage that the open thread end of the rolling bellows is outside the pressure chamber and is therefore not subjected to air pressure. However, the disadvantage is the folding of the rolling bellows around the outer guide, the reliable positioning of the overlapping ends of the bellows and rolling bellows, and the subsequent clamping from the outside using the clamping ring.

[0004] It is therefore the object of the invention to provide an air spring with two thread-reinforced bellows, the connection of which is simplified and improved compared to the prior art, and to provide a method for producing such an air spring, which is simplified and improved compared to the prior art.

[0005] The object underlying the invention is achieved with an air spring according to the features of the device claim and with a method for producing such an air spring according to the features of the method claim.

[0006] If the air spring according to the invention is combined with an integrated shock absorber, it is an air spring strut in which the exemplary connection of bellows and rolling bellows is also used.

[0007] The air spring is used in the chassis of a motor vehicle, particularly in an air spring system.

[0008] Preferred embodiments of the invention emerge from the respective subclaims and the following description of an embodiment with reference to the figures.

[0009] They show: Fig. 1 an air spring strut with an exemplary connection of two bellows, and Fig. 2 the detail A of the Fig. 1.

[0010] The Fig. Figure 1 shows an air spring strut 1 consisting of an air spring 2 with an integrated shock absorber 3 for a motor vehicle. The air spring 2 comprises a rolling piston 4, which is attached to the shock absorber 3. The shock absorber 3 serves to connect the air spring strut 1 to a wheel carrier. The air spring 2 also includes a cover 5, which connects the air spring strut 1 to the vehicle body. This standard installation position of the air spring strut 1 determines the "top / bottom" orientation. The longitudinal axis of the air spring strut 1 is marked L.

[0011] A tubular bellows 6 made of elastomeric material with thread reinforcement is pressure-tightly connected to the cover 5 through its first / upper end 7. The first bellows end 7 is attached to the mounting shaft of the cover 5 via a clamping ring, but can also be vulcanized. The reinforcement members of bellows 6 are aligned in a cross-ply direction, making this a cross-ply bellows. This design of the bellows is suitable for the cardanic pivoting movement of air spring strut 1 and is also considered particularly robust.

[0012] A separate elastomer bellows in the form of a rolling bellows 9 with thread reinforcement is pressure-tightly connected to the rolling piston 4 by its first / lower end 10. Here, too, the first end 10 of the rolling bellows is attached to the mounting shaft of the rolling piston 4 via a clamping ring. Here, too, the first end 10 can be vulcanized to the mounting shaft of the rolling piston 4. The reinforcement members of the rolling bellows 9 are aligned in the axial direction, making this an axial bellows. The axial bellows is soft and enables good spring properties.

[0013] In detail A, it can be seen that bellows 6 is connected to a second end 8 within a connection area 18 with a second end 11 of rolling bellows 9. The connection is made, for example, by vulcanizing bellows 6 with rolling bellows 9 in a green state, i.e. in the unvulcanized state. This type of connection is described below with the Fig. 2 is explained in more detail.

[0014] Due to the exemplary connection, bellows 6 and rolling bellows 9 together with rolling piston 4 and cover 5 delimit a volume-elastic pressure chamber 12. In addition, bellows 6 forms a fold 14 in the area of ​​the connection to cover 5, which fold is required for the cardanic deflection of air spring strut 1 and rolling bellows 9 forms a rolling fold 13, by means of which it rolls on the rolling piston 4.

[0015] Furthermore, bellows 6 and rolling bellows 9 are partially enclosed by a sleeve-shaped outer guide 15, which acts as a support corset to counteract the high pressure inside air spring 2 and thus limit lateral expansion. Outer guide 15 is held in an axial position on the connected bellows 6 and 9 by a clamping ring 16. Clamping ring 16 is arranged in the pressure chamber 12 of air spring 2 and positioned in the connection area between bellows 6 and rolling bellows 9.

[0016] A bellows 17 is provided to protect the rolling fold 13 from contamination and damage. Bellows 17 is attached to a lower end of the outer guide 15 and to a lower end of the rolling piston 4. The respective bellows ends are secured via a positive connection with an outwardly facing collar of the respective connecting part.

[0017] The Fig.Figure 2 shows detail A, which is used to explain the example connection of bellows 6 to rolling bellows 9. During production of the air spring, bellows 6 and rolling bellows 9 are first provided as unvulcanized blanks. In the case of rolling bellows 9, its second bellows end 11 is folded outwards around itself, creating a layer turn-up. This means that the outer side of the rolling bellows is turned inside out, so that a portion of the rolling bellows outer side is bonded. Due to the layer turn-up, a portion of the elastomeric rolling bellows inner side is now on the outside. The second bellows end 8 with the unvulcanized inner side of bellows 6 is now applied to this outer part of the unvulcanized inner side of rolling bellows 9.

[0018] The bellows 6 and rolling bellows 9 are then vulcanized, bringing them into their operational state and also into shape. The vulcanization process crosslinks the layer turn-up of the second rolling bellows end 11 in the contact area of ​​the folded-over outer side of the rolling bellows, and at the same time the outer inner side of the rolling bellows also crosslinks with the overlapping inner side of the second bellows end 11. This creates a pressure-tight connection between bellows 6 and rolling bellows 9, which requires no additional components and takes place in a single process step with the actual vulcanization of the bellows 6 and 9. The vulcanized connection of the two bellows 6 and 9 is advantageous over a clamped connection because with a clamped connection the clamping force decreases over time and thus the connection gradually becomes leaky. In addition, the manufacturing process has been simplified because the complex clamping process has been eliminated. List of reference symbols 1 air spring strut 2 air springs 3 shock absorbers 4 rolling pistons 5 lids 6 bellows 7 first bellows end 8 second bellows end 9 Bellows 10 first rolling bellows end 11 second bellows end 12 Printing room 13 Roll fold 14 folds 15 Outdoor tour 16 clamping ring 17 Bellows 18 Connection area L Longitudinal axis QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 209 899 A1

[0003]

Claims

[1] Air spring (2) for a motor vehicle, comprising a cover (5), wherein a thread-reinforced elastomer bellows (6) with a first bellows end (7) is fastened to the cover (5), and a rolling piston (4), wherein a thread-reinforced elastomer rolling bellows (9) with a first rolling bellows end (10) is fastened to the rolling piston (4), wherein a second bellows end (8) of the bellows (6) is connected within a connecting region (18) to a second rolling bellows end (11) of the rolling bellows (9), whereby a volume-elastic pressure chamber (12) is delimited, characterized byin that the second bellows end (11) is folded outwards in the connecting region (18), wherein the second bellows end (8) covers the folded second bellows end (11) on the outside, wherein an inner contact surface of the folded second bellows end (11) is cross-linked by means of vulcanization and a contact surface of the covering second bellows end (8) is cross-linked with the second bellows end (11) by means of vulcanization. [2] Air spring (2) according to claim 1, characterized by that the second bellows end (8) and the second rolling bellows end (11) point in a common direction. [3] Air spring (2) according to claim 1 or 2, characterized by that a clamping ring (16) is positioned within the pressure chamber (12) in the region of the connecting region (18), by means of which an outer guide (15) is held on the interconnected bellows (6) and rolling bellows (9). [4] Air spring (2) according to one of claims 1 to 3, characterized bythat the bellows (6) is designed as an axial bellows and the rolling bellows (9) as a cross-layer bellows, or that the bellows (6) is designed as a cross-layer bellows and the rolling bellows (9) as an axial bellows, or that the bellows (6) and the rolling bellows (9) are each designed as an axial bellows or as a cross-layer bellows. [5] Air spring (1) according to one of claims 1 to 4, characterized by that the air spring (1) is combined with an integrated shock absorber to form an air spring strut (1). [6] Method for producing an air spring (2) comprising the following steps: - Providing an unvulcanized bellows (6) in the blank state with a first bellows end (7) which is designed to be attached to a cover (5) of the air spring (2), - Providing an unvulcanized rolling bellows (9) in the blank state with a first rolling bellows end (10) which is designed to be attached to a rolling piston (4) of the air spring (2), characterized in that - a second bellows end (11) of the bellows (9) is folded outwards in the blank state, - after which a second bellows end (8) of the bellows (6) in the blank state is subsequently applied so as to cover the folded-over second rolling bellows end (11) on the outside, wherein in a subsequent vulcanization process an inner contact surface of the folded-over second rolling bellows end (11) is cross-linked and a contact surface of the covering second bellows end (8) is cross-linked with the second rolling bellows end (11).

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