External guide for an air spring of a motor vehicle consisting of a band and method for producing such an external guide

Abstract

An outer guide (1) for an air spring of a motor vehicle, the outer guide (1) being made of a plastic material, the outer guide (1) consisting of a band (2) wound in the circumferential direction, and an outer guide (1') for an air spring of a motor vehicle, the outer guide (1') comprising a hollow cylindrical base body (3), the base body (3) being wrapped several times in the circumferential direction with a band (2) to increase strength, and a method for producing an outer guide (1) for an air spring of a motor vehicle, comprising the following steps: - Placing a layer (7) of a strip (2) on a rotating mandrel (4), - Unwinding the tape (2) so that this layer is wound once around the mandrel (4), - heating a partial area of the layer (7) of the strip (2) by means of a heat source (5), and - Unwinding a further layer (8) of the strip (2) onto the heated portion of the strip (2), and - Press the further layer (8) with a pressure roller (6) so that the further layer (8) connects to the layer below.

Description

[0001] The invention relates to an external guide for an air spring of a motor vehicle according to the respective preamble of the independent device claims and the invention also relates to a method for producing an external guide for an air spring according to the preamble of 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 secured 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 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.

[0003] 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.

[0004] 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 ring located inside 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 inside the rolling bellows, which presses onto 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.

[0005] 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 from 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.

[0006] It is an object of the invention to provide an outer guide for an air spring which is light, thin and at the same time has high strength properties and to provide a method for producing an outer guide which is light, thin and has high strength properties.

[0007] The problem is solved by the features of the independent device claims and the features of the independent method claim. Preferred embodiments can be found in the respective subclaims and the following description of exemplary embodiments with reference to the figures.

[0008] They show: Fig. 1 a first exemplary external tour, Fig. 2 a second exemplary external guide, Fig. 3 a third exemplary external guide, and Fig. 4 a method for producing the first exemplary outer guide.

[0009] The Fig. 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.

[0010] 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.

[0011] By using multiple windings in certain areas, different wall thicknesses can be realized over the length of outer guide 1.

[0012] Such an outer guide, wound from a single strip, has the advantage that it can be manufactured with extreme tensile strength at 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 extremely lightweight.

[0013] 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.

[0014] 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.

[0015] An alternative external tour will be offered in the Fig. 2. The second exemplary outer guide 1' comprises a base body 3. Base body 3 is made, for example, of a thermoplastic, a duromer, or a metallic material.

[0016] For example, base body 3 is wrapped multiple times in the circumferential direction on the outside with tape 2. For example, tape 2 is wound in a spiral shape. Tape 2 can also be wound in multiple 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.

[0017] 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 1' to the air spring's rolling bellows.

[0018] In addition to the first embodiment according to Fig. 1 shows the Fig. 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 attach the outer guide 1" to the air spring's rolling bellows.

[0019] 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.

[0020] The Fig.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 shown with a dash-dot line, while strip 2 or layer 7 is shown with a solid line. After a first wrapping of strip 2 onto mandrel 4, a region of the first layer 7 is heated by means of a heat source 5. By rotating mandrel 4 (to the right in the sheet 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 in the longitudinal direction.

[0021] 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 dimension is reached, strip 2 is cut off and the outer guide can be removed from mandrel 4. List of reference symbols 1 outdoor tour 1' outside guide 1'' external guide 2 volumes 3 basic bodies 4 Thorn 5 Heat source 6 pressure roller 7 first layer of the tape 8 further layers of the band 9 attachments 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 209 491 A1

[0004]

Claims

[1] Outer guide (1) for an air spring of a motor vehicle, wherein the outer guide (1) is made of a plastic material, characterized by that the outer guide (1) consists of a band (2) wound in the circumferential direction. [2] External guide according to claim 1, characterized by that the band (2) is a thermoplastic material reinforced with glass or carbon fibers, wherein in particular the glass or carbon fibers are unidirectionally aligned. [3] External guide according to claim 1 or 2, characterized by that the tape (2) is wound unidirectionally. [4] External guide according to one of claims 1 to 3, characterized by that the outer guide (1) has different wall thicknesses in certain areas. [5] External guide according to one of claims 1 to 4, characterized by that the tape (2) is not wound on any body. [6] External guide according to one of claims 1 to 5, characterized bythat an attachment part is arranged at least at one end of the outer guide (1). [7] External guide according to claim 6, characterized by that the attachment part is at least partially inserted into the end of the outer guide (1) or that the attachment part is at least partially wrapped by the band (2) in the circumferential direction. [8] External guide (1') for an air spring of a motor vehicle, wherein the external guide (1') comprises a hollow cylindrical base body (3), characterized by that the base body (3) is wrapped several times with a band (2) in the circumferential direction to increase strength. [9] External guide according to claim 8, characterized by that the band (2) is a thermoplastic material reinforced with glass or carbon fibers, wherein in particular the glass or carbon fibers are unidirectionally aligned. [10] Method for producing an external guide (1) for an air spring of a motor vehicle, comprising the following steps: - Placing a layer (7) of a strip (2) on a rotating mandrel (4), - Continuous unwinding of the tape (2) so that this (7) layer is wound once around the mandrel (4), - heating a portion of the layer (7) of the strip (2) by a heat source (5), and - Continuously unwinding a further layer (8) of the strip (2) onto the heated portion of the strip (2), and - Pressing the further layer (8) using a pressure roller (6) so that the further layer (8) connects to the layer below (7). [11] Method according to claim 10, characterized by that the strip (2) is unwound unidirectionally onto the mandrel in several layers. [12] Method according to claim 10 or 11, characterized bythat the heating of the partial area of the layer (7) takes place up to a melting temperature of the band (2), so that by pressing the further layer (8) by means of the pressure roller (6) a material connection is created between the layers (7, 8). [13] Method according to one of claims 10 to 12, characterized by that the band (4) is unwound along a longitudinal axis of the mandrel (4) so that the longitudinally extending hollow cylindrical outer guide (1) is formed. [14] Method according to one of claims 10 to 13, characterized by that the band (2) is a thermoplastic material reinforced with glass or carbon fibers, wherein in particular the glass or carbon fibers are unidirectionally aligned.

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