Air spring strut with a thermoplastic air spring cover

Abstract

Air spring strut (1) for a motor vehicle comprising an air spring (2) with a shock absorber (3) for suspension and damping of vibrations of a motor vehicle chassis, wherein the air spring (2) comprises an air spring cover (4, 40) and a rolling piston (5), wherein a rolling diaphragm (6) made of elastomeric material is hermetically clamped between the air spring cover (4, 40) and the rolling piston (5), wherein the air spring cover (4, 40) comprises a damper bearing receptacle (45) in which a damper bearing (11) of the shock absorber (3) is arranged, and wherein the air spring cover (4, 40) comprises a clamping base (50) to which a first end of the rolling diaphragm (6) is connected, wherein at least the damper bearing receptacle (45) of the air spring cover (40) is made entirely of a plastic material, wherein the plastic material is a thermoplastic, characterized in thatthat the air spring cover (40) comprises several receiving devices (53) and several fastening means (52) for connecting the air spring strut (1) to the motor vehicle, wherein one of the fastening means (52) is at least partially embedded in each of the receiving devices (53), wherein the fastening means (52) are overmolded in the respective receiving devices (53) by the plastic material of the air spring cover (40).

Description

[0001] The invention relates to an air spring strut according to the preamble of claim 1.

[0002] An air suspension strut, such as that known from DE 10 2012 012 902 A1, is positioned between the vehicle chassis or a wheel carrier and the vehicle body. The air suspension strut typically comprises an air spring and a shock absorber. The air spring cushions the wheel, while the shock absorber dampens the vibrations of the wheel or the vehicle body.

[0003] The air spring essentially consists of an air spring cover, a rolling piston, and a bellows clamped between them in an airtight manner, defining a pressurized working chamber. The bellows is enclosed by a sleeve-shaped outer guide and rolls along the concentric rolling piston during compression, forming a rolling fold. The air spring strut is connected to the vehicle body via the air spring cover using appropriate fasteners.

[0004] The shock absorber, located within the air spring, is connected to the wheel carrier on one side and, with its piston rod extending into the damper tube, is mounted in the air spring cover via a damper bearing. Particularly during dynamic operation of the air spring strut, high tensile and compressive forces act on the cup-shaped bearing mount of the air spring cover. Since this bearing mount houses the shock absorber's damper bearing and simultaneously connects the entire air spring strut to the body, this component must exhibit exceptional strength properties.

[0005] As is well known, most large-volume air spring covers are made from at least two components. An identical material, usually a metal, is used for the integral connection of the components, from which the bearing support is made. Such a cover is known, for example, from DE 10 2013 212 982 A1.

[0006] The air spring cover of an air spring strut is subject to a wide range of requirements. As already mentioned, the entire air spring strut is connected to the vehicle body via the air spring cover. Furthermore, the air spring cover, as a pressure body or cover containing a large volume of air, represents part of the spring-effective internal volume of the air spring. Therefore, the air spring cover must also ensure a pressure-tight seal between the interior of the air spring and the outside. Furthermore, the rolling bellows is connected to a clamping base provided by the air spring cover using clamping rings. Finally, the air spring cover must also provide pressure-tight receptacles for the air connection and additional volume.

[0007] As the connecting element between the air spring strut and the chassis connection, high forces are transmitted through the air spring cover. These incoming and transmitted forces are both static in nature (load-bearing forces to support the vehicle's weight) and dynamic in nature (time-varying forces during driving due to the compression / rebound state), with the dynamic forces superimposing themselves on the static forces. At the shock absorber's connection point (damper mount), dynamic tensile and compressive forces act on the air spring cover, depending on the spring speed.

[0008] The forces acting on the air spring cover of an air spring strut are also caused by the internally pressurizing gas force of the spring-acting cover space, which can be divided into static and dynamic components due to the changing pressure.

[0009] From a functional perspective, to ensure complete airtightness of the air spring cover, it would be advantageous to manufacture it as a closed shell made of a single material or a group of materials that can be easily bonded together, with this component not being penetrated by other components, for example, with more optimal strength properties. Such a penetration would, in turn, require special measures to seal it. Any seal is vulnerable to pressure leaks and also represents an additional process step.

[0010] A composite lid made of different materials, plastic and metal, is known, for example, from DE 10 2015 100 281 A1.

[0011] In this case, it is a metallic upper part that is overmolded with a thermoplastic material. This creates a composite part that meets the sealing and strength requirements. A flange made of a metallic material is provided for the damper bearing, which also forms the connection to the chassis. The metallic damper bearing mount represents a good solution in terms of strength requirements, but is very heavy due to its mass density. For this reason, the rest of the cover shell of the air spring cover is also made of a thermoplastic material to save weight. The flange is at least partially surrounded by the thermoplastic material, which ensures the gas-tightness of the air spring cover.

[0012] The disadvantage of this solution, however, is that pressure-tightness requires a pressure-tight connection between the inner metal flange and the pressure-tight cover shell facing the interior of the cover. This is at least achieved by overmolding the damper bearing mount on the inside with the thermoplastic material. This is further provided with an insert and a guide for the piston rod to ensure sufficient tightness. Furthermore, the damper bearing mount is closed on top with a pressure-tight cover. All of these measures are necessary due to the aforementioned perforation.

[0013] DE 10 2012 012 995 A1 discloses an air spring strut comprising a spring cup for the top connection of a rolling bellows and for connecting the air spring strut to the motor vehicle. The spring cup has an annular extension and is a plastic injection-molded part. The extension is partially enclosed by a guide sleeve, and an auxiliary spring is arranged below the extension. A steel support plate is provided above the annular spring cup, which is located in the spring cup and through which the air spring strut is attached to the vehicle body. The damper bearing of the shock absorber is located in this support plate.

[0014] The general use of fiber-reinforced thermoplastics in free-standing air springs is known from EP 0 264 573 B1.

[0015] The Fig. 4 of DE 10 2007 004 037 A1 shows an air spring strut which can be connected to the motor vehicle via fastening bolts attached to it.

[0016] DE 10 2004 031 875 A1 describes a multi-part air spring cover of an air spring strut, with the inner part being made of plastic.

[0017] Furthermore, DE 10 2017 210 543 A1 discloses an air spring cover of an air spring strut with several fastening bolts for connection to the motor vehicle, wherein the fastening bolts are pushed through a radially outwardly directed flange of the air spring cover.

[0018] The object of the invention is to provide an improved air spring cover of an air spring strut, which ensures gas tightness in a simple manner, can be manufactured with a low weight and yet has sufficient stability and strength.

[0019] The problem underlying the invention is solved with the features of the independent patent claim.

[0020] According to the invention, an air spring strut for a motor vehicle is provided, comprising an air spring with a shock absorber for cushioning and damping vibrations of a motor vehicle chassis, wherein the air spring comprises an air spring cover and a rolling piston, wherein a rolling bellows made of elastomeric material is clamped in an airtight manner between the air spring cover and the rolling piston, wherein the air spring cover comprises a damper bearing receptacle in which a damper bearing of the shock absorber is arranged, and wherein the air spring cover comprises a clamping base to which a first end of the rolling bellows is connected, wherein at least the damper bearing receptacle of the air spring cover is made entirely of a plastic material, wherein the plastic material is a thermoplastic, wherein the air spring cover comprises a plurality of receiving devices and a plurality of fastening means for connecting the air spring strut to the motor vehicle,wherein one of the fastening means is at least partially embedded in each of the receiving devices, wherein the fastening means in the respective receiving devices are encapsulated by the plastic material of the air spring cover.

[0021] Experts generally have reservations about manufacturing the air spring cover of an air spring strut, i.e., the shock absorber mount, exclusively from plastic. This is because plastic does not meet the strength requirements of a metallic material, especially during dynamic operation. Therefore, a metal damper mount was always used.

[0022] It has been found that a damper bearing mount made entirely of a thermoplastic material can meet the force requirements. This means, in particular, that the damper bearing mount is not reinforced by any additional element. No additional component made of a different material is used to support the strength of the damper bearing mount. Only the damper bearing mount, formed from the same material as the air spring cover, is intended to support the shock absorber bearing.

[0023] With appropriate wall thickness in the wall and base areas, the damper bearing mount meets the force requirements and proves to be extremely stable during continuous operation. This means that the dynamic tensile and compressive forces emanating from the shock absorber are successfully absorbed by the thermoplastic material of the damper bearing mount and transferred to the vehicle body.

[0024] Thermoplastics exhibit good molding and welding properties. Therefore, these materials are particularly suitable for the air spring cover of an air spring strut. The use of thermoplastics enables a wide variety of geometries to achieve the largest possible cover volume. At the same time, the thermoplastic possesses sufficient strength in the damper bearing support area, which is largely determined by a variable filler content. Therefore, the thermoplastic is preferably fiber-reinforced. Such thermoplastics can be PA6, PA6.6, or PA12.

[0025] The shock absorber's damper bearing is inserted into the internal damper bearing mount. The damper bearing provides elastic decoupling for the shock absorber and is designed to dampen the vibrations acting on the air spring cover. Therefore, the damper bearing typically includes a support piece, which is attached to the free end of the piston rod with a nut. The support piece is, in turn, surrounded by an elastomer element and can be vulcanized together with it. Typically, the elastomer element rests with its underside in the damper bearing mount, while its radial outer wall rests against the cylindrical part of the damper bearing mount.

[0026] In order to connect the air spring strut to a designated connection area of ​​the motor vehicle body, a plurality of receiving devices and fastening means are provided according to the invention on the axial upper side of the air spring cover or the first cover part. The fastening means, e.g. as screw bolts, comprise a shaft with a head or anchor. The head or anchor is inserted into a receiving device provided in the air spring cover. The receiving devices are axially extending recesses in the air spring cover. Since the air spring cover is injection-molded from a plastic material, the fastening means with their heads or anchors in the respective receiving devices are overmolded by this plastic material, whereby they are securely held in the receiving devices. The receiving devices are distributed circumferentially on the annular upper side of the air spring cover.

[0027] Thus, the air spring cover with its damper bearing mount made of thermoplastic material and the mounting devices represents the main force path of the tensile and compressive forces emanating from the shock absorber into the vehicle body.

[0028] The damper bearing mount is preferably cup-shaped. The cup shape is characterized by at least a base and a hollow cylindrical wall. It is ideally suited to accommodate the damper bearing and is easily manufactured using plastic injection molding.

[0029] Preferably, the base of the damper bearing mount is made of the thermoplastic material. Furthermore, the wall of the damper bearing mount is also made of the thermoplastic material. Furthermore, the damper bearing mount comprises a collar by means of which the air spring strut is connected to the vehicle body. The collar, or edge, extends radially outward from the hollow cylindrical wall. The collar is preferably made of the thermoplastic material.

[0030] All three areas of the cup-shaped damper mount transfer the acting forces into the body. Their thermoplastic construction has proven to be extremely stable and load-bearing.

[0031] According to a further preferred embodiment, a rib structure with a plurality of stiffening ribs is provided inside the air spring cover. The rib structure is formed on the inside of the air spring cover by the plurality of stiffening ribs that are provided between the outer side of the damper bearing mount and the inner side of the cover shell, connecting them. The rib structure increases the overall strength of the air spring cover, in particular preventing bursting due to internal gas pressure.

[0032] Preferably, the stiffening ribs are molded from the same thermoplastic material as the air spring cover. This is where the advantages of the plastic injection molding process come into play, as it allows a wide variety of rib structures to be molded from the same material as the air spring cover in a single process.

[0033] According to another preferred embodiment, the clamping base is provided with a metallic reinforcement ring on the inside. The bellows is connected to the clamping base at the end. This means that an end section of the upper end of the bellows is in surface contact with the axial contact surface of the clamping base and is secured to it by a clamping or tensioning ring. Depending on requirements, a metallic ring is placed on the inside of the clamping base to reinforce it.

[0034] According to another preferred embodiment, the clamping base is made of the thermoplastic material. Like the damper bearing mount, the clamping base of the air spring cover is now made of the thermoplastic material. This clamping base is extremely strong. With appropriate wall thickness, it also meets the force requirements for the rolling bellows clamp.

[0035] According to another preferred embodiment, the air spring cover is made entirely of thermoplastic material in one piece. For the first time, the entire air spring cover is made of a thermoplastic material. In this design, the air spring cover does not have any openings in its inner structure for force absorption or in its outer structure for clamping the rolling bellows. This eliminates the need for separate sealing measures, such as the provision of sealing rings or overmolding of the damper bearing mount.

[0036] According to another preferred embodiment, the air spring cover is designed in multiple parts, comprising at least a first cover part, which encloses the damper bearing receptacle, and a second cover part, which encloses the clamping base, wherein at least the first cover part is made of the thermoplastic material. Depending on the requirements for the volume to be enclosed by the air spring cover, it is designed in two parts. While the first cover part represents the damper bearing receptacle, the second cover part forms a volume-enclosing cover or a shell, which delimits the spring-effective cover space. Dividing the cover into two parts increases the design freedom required to provide a large cover space.

[0037] Preferably, the second cover part and its clamping base are made of a thermoplastic material. Like the one-piece cover, in this embodiment the second cover part, with its outer wall and clamping base, is also made of one of the aforementioned thermoplastic materials. This can be the same thermoplastic material as the first cover part, but does not necessarily have to be the same. For example, the first cover part is made of PA12 and the second cover part of PA6.

[0038] Particularly preferably, the first and second cover parts are integrally joined. The choice of an injection-moldable and weldable thermoplastic material not only enables new shapes but also simplifies manufacturing. This allows the two cover parts to be integrally joined in their joining area using conventional plastic welding processes.

[0039] The rolling bellows, together with the air spring cover and the rolling piston, defines a working chamber filled with compressed air. This volume-elastic working chamber represents the effective spring volume of the air spring.

[0040] The air spring cover preferably includes a cover chamber. This cover chamber, preferably a large-volume air chamber, expands the working space of the air spring and thus reduces its spring stiffness.

[0041] The air spring strut is used in a chassis, preferably in an air spring system, for a motor vehicle.

[0042] Further preferred embodiments of the invention emerge from the subclaims and the following description of an embodiment with reference to the figures.

[0043] It shows Fig. 1 an air spring strut according to the state of the art, Fig. 2 a first embodiment of an air spring cover, and Fig. 3 a second embodiment of an air spring cover.

[0044] The Fig. Figure 1 shows a known air spring strut 1 with the essential components, air spring 2 and shock absorber 3. Air spring 2 comprises an air spring cover 4, a rolling piston 5, and a rolling bellows 6 with a sleeve-shaped outer guide 7 surrounding the latter. A shock absorber 3 is provided within air spring 2, with shock absorber 3 comprising a damper tube 14, a piston rod 15 that can be inserted into the damper tube, and a damper bearing 11.

[0045] Air spring strut 1 fulfills two functions: first, air spring 2 generates load-bearing force, while shock absorber 3 is responsible for linear guidance. Using fasteners on the air spring cover 4, air spring strut 1 can be attached to a vehicle body on the one hand, and secondly, via a shock absorber eyelet (not shown), to a wheel carrier of the vehicle chassis, thereby providing suspension and damping for the vehicle.

[0046] This regular installation position of an air spring strut determines the “top / bottom” orientation.

[0047] Air spring 2 comprises a rolling bellows 6 made of elastomeric material, wherein the rolling bellows 6, together with the air spring cover 4 and the rolling piston 5, defines an airtight, volume-elastic working chamber 10 that can be filled with compressed air. The tubular rolling bellows 6 is attached at its first end to the air spring cover 4 and at its second end to the rolling piston 5 via clamping rings 18 to the connection areas of these air spring components.

[0048] During relative movements along the longitudinal axis L of the air spring strut 1 between the air spring cover 4 and the rolling piston 5, the rolling bellows 6 rolls on the concentric rolling surface of the rolling piston 5, forming a rolling fold 8. Furthermore, the rolling bellows 6 forms a cardanic fold 9 on the air spring cover 4, which acts as a cardanic bearing. At the same time, the rolling bellows 6 is provided with embedded reinforcement members.

[0049] Particularly in the case of the comfortable axial bellows, i.e., with reinforcements aligned in the axial direction, external guides 7 are used to limit the lateral expansion of the rolling bellows 6. The external guide 7 is clamped to the rolling bellows 6 by an internal clamping ring 12 provided in the working chamber 10.

[0050] To protect the rolling fold 8 from contamination, a bellows 19 is provided, which is fastened, for example, to the wheel carrier-side end area of ​​the outer guide 7 and to the damper tube 14.

[0051] An auxiliary spring 16 is arranged on the underside of the air spring cover 4, facing the shock absorber. The auxiliary spring 16 has a through-bore for the piston rod 15 and thus encloses it. During compression, the end face of the damper tube 14 moves toward the air spring cover 4, which is why the auxiliary spring 16 serves as a travel limiter and dampens any forces acting on the air spring cover 4.

[0052] Damper tube 14 of shock absorber 3 is provided within roll-off piston 5 or is at least partially surrounded by the hollow-cylindrical roll-off piston 5. Roll-off piston 5 can be mounted upright on the damper tube via a support ring 17 or suspended from the end face of damper tube 14 via a bearing element 13. A combination of upright and suspended roll-off piston 5 is also possible, as shown in the figure. It is also known to manufacture roll-off piston 5 from a light metal such as aluminum or a fiber-reinforced plastic.

[0053] With a stationary rolling piston 5, a sealing system 20, e.g., consisting of elastomer sealing rings, is provided between its end region facing the wheel carrier and the opposite outer wall of the damper tube 14. This serves to seal the working chamber 10 of the air spring 2, which can be expanded within the rolling piston, from the outside.

[0054] In the Fig. 2 shows a one-piece air spring cover 40 in vertical section.

[0055] The air spring cover 40 of an exemplary air spring strut comprises an internal, cup-shaped damper bearing mount 45 into which the damper bearing of a shock absorber is inserted. At the same time, the entire air spring strut is connected to a motor vehicle body (not shown) by means of the air spring cover 40.

[0056] To support the damper bearing, the internal cup-shaped damper bearing mount 45 comprises a cup base 46 with a through-bore for the shock absorber piston rod. Extending from the cup base 46 is a hollow cylindrical cup wall 47, formed from the material of the air spring cover 40. At the upper edge of the cup wall 47, this wall merges into a radially outwardly extending cup collar 48. Finally, the cup collar 48 is folded downwards and forms a clamping base 50 for the rolling bellows connection.

[0057] Furthermore, on the underside of the damper bearing holder 45, ie on the side of the pot base 46 facing away from the connection to the vehicle body, an additional spring pot 49 is provided, in which an additional spring is inserted.

[0058] To ensure pressure-tight sealing of the damper bearing, it is closed from above with a cover cap when installed. For this purpose, annular grooves or tapers are formed on the inner wall of the damper bearing mount 45 and the inside of the cup wall 47. The cover cap is inserted into these and pressed into place.

[0059] Due to the cup collar 48 turned over towards the clamping base 50, the air spring cover 40 at least partially provides a cover space 44 which, as an air chamber extension of the working space of the air spring, reduces its spring stiffness.

[0060] The cup collar 48 also includes receiving devices 53 for fastening means. Fasteners, or the shaft and head of screw bolts, are inserted into the receiving device 53 and overmolded with the material of the air spring cover 40, thus securing them in place. The receiving devices 53 are distributed circumferentially on the cup collar 48 and extend axially into it. The openings of the receiving devices open at the axial surface of the cup collar 48. For example, three such receiving devices with respective fastening means are provided. Consequently, the air spring cover 40 is screwed to the motor vehicle body using the fastening means in a force-fitting manner.

[0061] A key aspect of the air spring cover 40 of the exemplary air spring strut is its choice of material.

[0062] In particular, the structurally and strength-relevant area of ​​the air spring cover 40, specifically the damper bearing mount 45, is made of thermoplastic or a thermoplastic material. It has been proven that with appropriate design of the cup base 46 and design of the cup wall 47, the thermoplastic material meets the strength requirements placed on it. This is achieved, for example, by designing the damper bearing mount in such a way that a direct force path is created from the cup base 46 via the cup wall 47 into the mounting devices 53. This means, above all, that the tensile and compressive forces acting on the damper bearing mount 45 are reliably absorbed and transmitted into the vehicle body. At the same time, the thermoplastic damper bearing mount 45 is lighter than a comparable damper bearing mount made of a metallic material.

[0063] A ring-shaped clamp base 50 provides an axial contact surface for connecting the upper end of the rolling bellows. In a further embodiment, the clamp base 50 is reinforced on the inside with a metal reinforcement ring 51. Advantageously, the clamp base 50 of the air spring cover 40 is made of the same thermoplastic material as the cover 40 itself. Constructing the clamp base 50 from a thermoplastic material results in high strength and low density. Consequently, the air spring cover 40 with the clamp base 50 made of a thermoplastic material ensures cost-effective production and an overall lighter air spring strut.

[0064] The Fig. 3 shows a perspective view of a multi-part air spring cover 40 in vertical section of an exemplary air spring strut.

[0065] In order to meet the requirements placed on the air spring cover 40 (force absorption and volume formation), it has been divided into several cover parts 41, 42.

[0066] A first cover part 41 serves to accommodate the shock absorber bearing and, to some extent, also to attach the air spring strut to a motor vehicle body (not shown). To support the damper bearing, the first cover part 41 comprises an internal cup-shaped damper bearing mount 45. This damper bearing mount 45, formed from the material of the first cover part 41, comprises a cup base 46 with a through-bore for the shock absorber piston rod. Extending axially from the cup base 46 is a substantially hollow-cylindrical cup wall 47, which is formed from the material of the first cover part 41. At the upper edge of the cup wall 47, this wall merges into a radially outwardly extending cup collar 48.

[0067] Furthermore, on the underside of the damper bearing holder 45, ie on the side of the pot base 54 facing away from the connection to the motor vehicle body, an additional spring pot 49 is provided, which is also formed from the material of the first cover part 41 and in which an additional spring is inserted.

[0068] To ensure pressure-tight sealing of the damper bearing, it is closed from above with a cover cap when installed. For this purpose, an annular groove and a tapered portion are formed on the inner wall of the damper bearing mount 45 and the inside of the cup wall 47. The cover cap is inserted into this groove and pressed into place.

[0069] Part of the spring-acting cover volume is realized through the shape and design of a second cover part 42. The outer wall of the second cover part 42 significantly defines and limits a cover space 44. The air chamber of the cover space 44 expands the working space of the air spring and provides a more comfortable spring response.

[0070] In addition, the second cover part 42 is intended for the rolling bellows connection and therefore includes an annular clamping base 50 with an axial contact surface for the upper rolling bellows end. For improved clamping, the clamping base 50 is reinforced on the inside by a metallic reinforcement ring 51. Reinforcement ring 51 counteracts the radial contact force of the subsequent rolling bellows clamp and thus supports the rolling bellows clamp with regard to its tightness requirements.

[0071] The air spring cover 40 is therefore composed of cover parts 41 and 42. For this purpose, both cover parts 41 and 42 provide a joining area, through which both cover parts 41 and 42 are welded together.

[0072] In order to make the air spring cover 40 tear- and burst-resistant, a plurality of stiffening ribs 54 are formed inside it and from the material of the cover parts 41, 42. Starting from the outer wall of the pot wall 47, stiffening ribs 54 are distributed toward the inner wall of the first and second cover parts 41, 42.

[0073] Additionally, the stiffening ribs 54, which are formed from the material of the first and second cover parts 41 and 42, have the advantage of increasing their joint area. This means that the contact area to be welded between the two cover parts 41 and 42 is increased by the stiffening ribs 54, thus also increasing the bond strength of the two cover parts 41 and 42.

[0074] A key aspect of the Fig. 3 is also the choice of thermoplastic material. The designs of the air spring cover 40 for this material Fig. 2 apply in an equivalent manner to the air spring cover 40 of the Fig. 3. This also applies in particular to the strength requirements of the damper bearing support 45 of the multi-part air spring cover 40.

[0075] The second cover part 42 is also made of a thermoplastic material. Fiber-reinforced thermoplastics are preferably considered for the volume-forming outer wall of the second cover part 42. Such materials can be polyamide (PA6, PA6.6, PA12) filled with long glass fibers or carbon fibers.

[0076] Furthermore, the Fig. 3 is characterized by its thermoplastic clamping base 50. The same applies to the air spring cover of the Fig. 2 mentioned versions in an equivalent manner for the multi-part air spring cover 40 of the Fig. 3. In a further embodiment, the clamping base 50 is reinforced on the inside with a metal reinforcing ring 51. List of reference symbols 1 air spring strut 2 air springs 3 shock absorbers 4 air spring covers 5 rolling pistons 6 rolling bellows 7 External tour 8 roll fold 9 Cardanic fold 10 work space 11 damper bearings 12 inner clamping ring 13 Bearing element 14 Damper tube 15 Piston rod 16 additional spring 17 Support ring 18 clamping ring 19 Bellows 20 Sealing system 40 air spring covers 41 first lid part 42 second cover part 44 Lid space 45 Damper bearing mount 46 Pot bottom 47 Pot wall 48 pot collars 49 Additional spring pot 50 clamp base 51 Reinforcement ring 52 fasteners 53 mounting devices 54 stiffening ribs

Claims

[1] Air spring strut (1) for a motor vehicle, comprising an air spring (2) with a shock absorber (3) for cushioning and damping vibrations of a motor vehicle chassis, wherein the air spring (2) comprises an air spring cover (4, 40) and a rolling piston (5), wherein a rolling bellows (6) made of elastomeric material is clamped in an airtight manner between the air spring cover (4, 40) and the rolling piston (5), wherein the air spring cover (4, 40) comprises a damper bearing receptacle (45) in which a damper bearing (11) of the shock absorber (3) is arranged, and wherein the air spring cover (4, 40) comprises a clamping base (50) to which a first end of the rolling bellows (6) is connected, wherein at least the damper bearing receptacle (45) of the air spring cover (40) is made entirely of a plastic material, wherein the plastic material is a thermoplastic, characterized byin that the air spring cover (40) comprises a plurality of receiving devices (53) and a plurality of fastening means (52) for connecting the air spring strut (1) to the motor vehicle, wherein one of the fastening means (52) is at least partially embedded in each of the receiving devices (53), wherein the fastening means (52) in the respective receiving devices (53) are encapsulated by the plastic material of the air spring cover (40). [2] Air spring strut (1) according to claim 1, characterized by that the thermoplastic is fiber-reinforced. [3] Air spring strut (1) according to claim 1 or 2, characterized by that a rib structure with a plurality of stiffening ribs (44) is provided inside the air spring cover (40). [4] Air spring strut (1) according to claim 3, characterized by that the stiffening ribs (44) are formed from the thermoplastic material of the air spring cover (40). [5] Air spring strut (1) according to one of claims 1 to 4, characterized by that the clamping base (50) is provided on the inside with a metallic reinforcing ring (51). [6] Air spring strut (1) according to one of claims 1 to 5, characterized by that the clamping base (50) is made of the thermoplastic material of the air spring cover (40). [7] Air spring strut (1) according to one of claims 1 to 6, characterized by that the air spring cover (40) is made in one piece and entirely from the thermoplastic material. [8] Air spring strut (1) according to one of claims 1 to 7, characterized by that the air spring cover (40) is designed in several parts, at least comprising a first cover part (41) which comprises the damper bearing receptacle (45), and a second cover part (42) which comprises the clamping base (50), wherein at least the first cover part (41) is made of the thermoplastic material. [9] Air spring strut (1) according to claim 8, characterized bythat the second cover part (42) and its clamping base (50) are made of a thermoplastic material. [10] Air spring strut (1) according to claim 8 or 9, characterized by that the first and second cover parts (41; 42) are integrally connected to one another.

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