Outer guide for an air spring of a motor vehicle comprising a strip

Abstract

The invention relates to an outer guide (1'') for an air spring of a motor vehicle, wherein the outer guide (1'') is produced from a plastic material, wherein the outer guide (1'') comprises a strip (2) wound in the peripheral direction, wherein the strip (2) is a thermoplastic material reinforced with glass or carbon fibres, wherein an attachment part (9) is arranged at least at one end of the outer guide (1), wherein the attachment part (9) is plugged at least partially into the end of the outer guide (1), or the attachment part (9) is wound in the peripheral direction by the strip (2) at least in regions.

Description

[0001] External guide for an air spring of a motor vehicle consisting of a band

[0002] The invention relates to an external guide for an air spring of a motor vehicle according to the preamble of patent claim 1.

[0003] 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 secured between a cover and a rolling piston, are known in a wide variety of designs. During operation, the air spring is subjected to internal overpressure, and the rolling bellows rolls during spring movements, forming a rolling fold on the outer surface of the concentric rolling piston. To limit expansion, the rolling bellows is enclosed by a sleeve-shaped outer guide.

[0004] These air springs use external guides to limit the radial expansion of the bellows. The external guide also provides a rolling surface for the bellows' folds.

[0005] Such external guides are typically made of aluminum and are radially plastically reduced by means of externally acting clamping jaws and clamped onto a support located within the rolling bellows. In this way, the external guide is attached to the rolling bellows. Designs are also known in which the external guide is attached by means of a clamping ring located within the rolling bellows, which presses against the external guide from the inside. Furthermore, external guides are also known that are made of a plastic material by injection molding. Such an external guide is known, for example, from DE 10 2019 209 491 A1.

[0006] DE 10 2018 216 023 A1 discloses an outer guide for an air spring, wherein the outer guide is made of fiber-reinforced plastic and has a banded design. Furthermore, DE 10 2019 209 899 A1 discloses an outer guide for an air spring made of plastic with glass fiber reinforcement. Furthermore, EP 4 378 662 discloses a method for producing wound plastic tubes, in which the tube body is produced by winding a flat, fiber-reinforced strip material with a thermoplastic or thermosetting polymer matrix onto a heated winding core, while the polymer matrix is ​​melted by laser irradiation to form a material bond between two superimposed layers of the strip material. The strip material is thermoplastic and unidirectionally fiber-reinforced.Also known from DE 69023 302 T2 is a method for producing a hollow body which is produced by unidirectionally doubling a plurality of continuous fibers in ribbon form with a thermoplastic resin as a matrix.

[0007] Due to the increasingly stringent sustainability requirements for motor vehicles, components such as air springs must also be rethought. The outer guides of an air spring, traditionally made of deep-drawn aluminum, are disadvantageous in this case due to the CO2 emissions during production, and increasing the recycled content of the required special material is also a major challenge.

[0008] The object of the invention is to provide an external guide for an air spring which is light, thin and at the same time has high strength properties.

[0009] The problem is solved by the features of patent claim 1. Preferred embodiments can be found in the subclaims and the following description of exemplary embodiments with reference to the figures.

[0010] They show:

[0011] Fig. 1 shows a first exemplary external guide,

[0012] Fig. 2 a second exemplary external guide,

[0013] Fig. 3 shows a third exemplary outer guide, and Fig. 4 shows a method for producing the first exemplary outer guide.

[0014] Figure 1 schematically shows a first exemplary outer guide 1, which consists of a band 2 wound in the circumferential direction. Band 2 is wound, for example, in a spiral shape. This creates the outer guide 1 with an elongated extension. Outer guide 1 is a hollow cylindrical body. Band 2 is wound, for example, several times in several layers. Band 2 is wound, for example, unidirectionally. This means that it is wound in only one direction. Band 2 can have various widths.

[0015] Tape 2, for example, is a thermoplastic material reinforced with glass or carbon fibers. It is a continuous fiber-reinforced tape with unidirectionally aligned reinforcing fibers.

[0016] By using multiple windings in some areas, different wall thicknesses can be realized over the length of outer guide 1.

[0017] Such an outer guide, wound from a single strip, has the advantage that it can be manufactured with extreme tensile strength and a low thickness. This means that outer guides with both low wall thickness and low mass are possible. Thus, thin wall thicknesses of 1 mm to 1.5 mm are feasible, and due to this thin wall thickness, the outer guide is very lightweight.

[0018] The tensile strength at a thickness of 0.25 mm is 800 to 950 MPa for glass fiber reinforced strip material and 1700 to 1950 MPa for carbon fiber reinforced strip material. Compared to aluminum outer guides, a CO2 reduction of 1 / 5 is possible.

[0019] High flexibility through the integration of additional elements for clamping contours and bellows connections (thermoplastic, thermoset, metallic). High flexibility through variable wall thicknesses for high-stress areas.

[0020] An alternative outer guide is shown in Figure 2. The second exemplary outer guide T comprises a base body 3. Base body 3 is made, for example, of a thermoplastic, a duromer, or a metallic material.

[0021] For example, base body 3 is wrapped several times in the circumferential direction on its outside with tape 2. For example, tape 2 is wound spirally. Tape 2 can also be wound in several layers around base body 3 and have different widths. Tape 2 is also a thermoplastic material reinforced with glass or carbon fibers. Tape 2 is preferably a continuous fiber-reinforced tape and is unidirectionally oriented or wrapped.

[0022] Such an outer guide 1' has the advantage that the ends of the base body 3 can be used to connect additional air spring components that require a certain shape. For example, bellows can be connected, or the base body can be used to clamp the outer guide T to the air spring's rolling bellows.

[0023] In addition to the first embodiment shown in Figure 1, Figure 3 shows a third exemplary outer guide 1", which consists of strip 2 and accommodates an attachment 9 at each end. Attachments 9 are made, for example, of a thermoplastic, a duromer, or a metallic material. They also serve to connect additional air spring components or to fasten the outer guide 1" to the rolling bellows of the air spring.

[0024] For this purpose, attachments 9 are either partially inserted into the respective end of the outer guide 1" wound from strip 2 or are partially wrapped with strip 2.

[0025] Figure 4 schematically shows a method for producing an outer guide for an air spring of a motor vehicle. A strip 2, which is preferably a thermoplastic material reinforced with glass or carbon fibers, is provided, with strip 2 being unwound, for example, from a roll not shown. Strip 2 is unwound in a first layer 7 onto a rotatable mandrel 4. Mandrel 4 is represented by a dash-dot line, while strip 2 or layer 7 is represented by a solid line. After a first wrapping of strip 2 onto mandrel 4, a region of the first layer 7 is heated by a heat source 5. By rotating mandrel 4 (to the right in the blade direction), the heated portion of layer 7 moves under another layer 8 of strip 2. At this point, the upper layer 8 is pressed against the underlying layer 7 by means of a pressure roller 6 to better bond layers 7 and 8.In addition, strip 2 is unwound at a specific angle to the circumferential direction to create an axially extending component. This means that to create an elongated outer guide, pressure roller 6, heat source 5, and the unwinding roller of strip 2 move along the longitudinal axis of mandrel 4, so that strip 2 is unwound spirally around mandrel 4. It is also possible for pressure roller 6, heat source 5, and the unwinding roller of strip 2 to remain stationary while mandrel 4 is displaced longitudinally.

[0026] It goes without saying that this process runs continuously and in multiple layers until the outer guide is produced in the desired dimensions. Once the desired dimensions are reached, strip 2 is separated, and the outer guide can be removed from dome 4.

[0027] List of reference symbols

[0028] 1 outdoor tour

[0029] 1' external guide 1" external guide

[0030] 2 volumes

[0031] 3 basic bodies

[0032] 4 Cathedral

[0033] 5 Heat source 6 Pressure roller

[0034] 7 first layer of the band

[0035] 8 further layers of the band

[0036] 9 attachments

Claims

Patent claims 1 . Outer guide (1 ") for an air spring of a motor vehicle, wherein the outer guide (1") is made of a plastic material, wherein the outer guide (1") consists of a band (2) wound in the circumferential direction, wherein the band (2) is a thermoplastic material reinforced with glass or carbon fibers, characterized in that an attachment part (9) is arranged at least at one end of the outer guide (1), wherein the attachment part (9) is at least partially inserted into the end of the outer guide (1) or the attachment part (9) is at least partially wrapped by the band (2) in the circumferential direction.

2. External guide (1") according to claim 1, characterized in that the glass or carbon fibers are aligned unidirectionally.

3. External guide (1") according to claim 1 or 2, characterized in that the band (2) is wound unidirectionally.

4. External guide (1") according to one of claims 1 to 3, characterized in that the external guide (1") comprises different wall thicknesses in certain regions.

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