Chassis component for a motor vehicle with at least one integrated vibration isolator, as well as a method for manufacturing the chassis component and a motor vehicle with such a chassis component

Abstract

Chassis component (10) for a motor vehicle, which is at least partially made of a fiber-reinforced plastic, wherein at least one vibration isolator (40, 41) is formed in the area of ​​the fiber-reinforced plastic by locally modifying the material structure to form the vibration isolator (40, 41), characterized in that the vibration isolator (40, 41) is formed by means of struts, wherein outer struts are arranged on an outer side of the chassis component (10) and inner struts are arranged on the opposite inner side, which faces a body (20), wherein sleeves (51, 52) are arranged between outer and inner struts and between inner struts and the body (20).

Description

[0001] The invention relates to a chassis component for a motor vehicle according to the preamble of claim 1.

[0002] When driving on a road, motor vehicles are exposed to vibrations caused by uneven road surfaces. These vibrations are transmitted through the tires to the suspension, sometimes even amplified. Isolators between chassis components and between the chassis and the body are therefore designed to minimize the energy transferred to the body. This minimizes perceptible vibrations and audible road noise.

[0003] The generic document DE 10 2013 201 075 A1 discloses a support structure made of fiber-reinforced plastic as a single- or multi-shell frame element and having elastic connection points for connection to an assembly. The elastic connection points are formed integrally with the frame element.

[0004] WO 2016 / 003 909 A1 discloses a composite compression limiter comprising a cylindrical body with an opening extending axially therethrough for receiving a fastener, the body being made of a continuous fiber polymer tape reinforced by a plurality of fibers in the range of approximately 20 wt.% to approximately 65 wt. A housing comprising a cylindrical inner and outer body is disposed around the body. Ribs extending radially between the inner and outer bodies are disposed between the inner and outer bodies.

[0005] Insulators integrated into chassis components are also already known. For example, US Pat. No. 7,347,414 B2 discloses an integrated unit consisting of an insulator and a spring element. US Pat. No. 5,788,262 describes a plastic upper support arm in which an insulator is incorporated.

[0006] US Pat. No. 7,077,390 B2, on the other hand, discloses a spring strut with a height-adjustable spring plate. This strut includes a cylinder, which can be part of a vibration damper or a gas spring. A chamber is provided on the cylinder side, which is at least partially filled with a formable material. Furthermore, an insulating sleeve, made of a plastic, for example, is arranged on the cylinder.

[0007] US 5 009 401 A describes an air spring unit with two-sided isolation. A spring damper is connected to a chassis component. US 7 108 253 B2 discloses a mounting assembly for use within a wheel suspension, which has a lower and an upper isolator. Both isolators are installed within the mounting assembly, which in turn are connected to a chassis component such as a subframe.

[0008] DE 102 23 517 A1 discloses a suspension for the drive unit of a vehicle, which is intended to isolate the drive unit from vibrations and rolling vibrations in the area between two parallel frame longitudinal members. The drive unit consists of the vehicle's engine and transmission. A so-called "focused drive unit suspension" is used at the rear suspension points, with the suspension consisting of a suspension unit integrated with a vibration isolator at each of four suspension points. For example, rubber elements vulcanized to chassis components are used.

[0009] Isolators typically consist of rubber and metal components called "chassis bushings" or "chassis mounts." These components are manufactured separately from chassis components such as subframes and control arms. They must meet a complex set of targets regarding isolation, durability, corrosion, etc. The isolation components are installed into the structural components of the chassis in separate assembly steps. This may include, for example, pressing bushings into control arms and calibrating the assembly.

[0010] However, the options for tuning the stiffness of the bushings are limited. This is particularly true for the stiffness in different directions of the bushings compared to fundamental requirements such as durability. Furthermore, the manufacturing of bushings is a time-consuming chemical, thermal, and mechanical process. Furthermore, the installation of the bushings often entails conflicting requirements regarding press-in forces during installation, the limits of press-out safety during use, and recalibration due to tight connections. Overall, the use of separate bushings for isolation purposes therefore leads to complex and risky manufacturing and assembly conditions.

[0011] Furthermore, it is known to manufacture chassis components of a motor vehicle from fiber-reinforced plastic. Carbon-fiber-reinforced plastic is used in particular. For example, DE 10 2011 085 383 A1 discloses an axle support for a motor vehicle consisting of an upper shell and a lower shell made of carbon-fiber-reinforced plastic, with the two shells together forming a hollow body. Vibration-isolating elements made of fiber-reinforced plastic are also known, as proposed, for example, in CN 1915698 A.

[0012] However, given the state of the art shown, the area of ​​chassis components with vibration isolators still offers room for improvement.

[0013] The invention is based on the object of providing a chassis component with at least one insulator in which the manufacturing and assembly conditions are simpler than in known solutions.

[0014] According to the invention, the object is achieved by a chassis component having the features of claim 1.

[0015] A chassis component for a motor vehicle is disclosed, which is at least partially made of a fiber-reinforced plastic, wherein at least one vibration isolator is formed in the region of the fiber-reinforced plastic by locally modifying the material structure to form the vibration isolator. According to the invention, the vibration isolator is formed by means of struts, wherein outer struts are arranged on an outer side of the chassis component and inner struts are arranged on the opposite inner side, which faces a body, wherein sleeves are arranged between outer and inner struts and between inner struts and the body.

[0016] Further, particularly advantageous embodiments of the invention are disclosed in the dependent subclaims.

[0017] It should be noted that the features and measures listed individually in the following description can be combined with one another in any technically reasonable manner and show further embodiments of the invention.

[0018] The chassis component for a motor vehicle is made at least partially of a fiber-reinforced plastic. The chassis component can be made partially or entirely of a fiber-reinforced plastic. A material mix can be used, for example, between fiber-reinforced plastic and steel and / or aluminum.

[0019] At least one vibration isolator is formed in the area of ​​this fiber-reinforced plastic by locally modifying the material structure of the fiber-reinforced plastic to form the vibration isolator. The vibration isolator is thus not formed by a separate component connected to the chassis component; rather, the vibration isolator is formed in the material structure of the chassis component itself and thus integrated into the chassis component. For this purpose, the material of the chassis component is locally modified in the area of ​​the isolator so that the material properties in this area have a vibration-reducing effect. Several such areas with a vibration-reducing effect can be provided to form several isolators.

[0020] The intended local change in the material structure can be created in various ways. For example, the material structure of the chassis component can be softer in the region of the at least one vibration isolator than in the surrounding area of ​​this vibration isolator. In an alternative embodiment of the invention, the material structure of the chassis component is thinner in the region of the at least one vibration isolator than in the surrounding area of ​​this vibration isolator. Both embodiments can also be combined, so that an isolator can also be formed by a local area that is both softer and thinner than the surrounding area.

[0021] Various additional elements can be integrated into the local material structure of the vibration isolator. These could include, for example, a stop buffer and / or other filler elements that can be used to achieve a desired alignment of stiffness differences.

[0022] The plastic used for the chassis component can be reinforced with one or more types of fibers. These can be carbon, glass, and / or aramid fibers. Epoxy resin, for example, can be used as the plastic matrix.

[0023] The chassis component itself can be, in particular, a subframe or a control arm, e.g., a longitudinal control arm and / or a transverse control arm. For both types of chassis components, an integrated vibration isolator according to the invention can be advantageously used to enable less complex manufacturing and assembly of the respective chassis component.

[0024] The integration of an isolator or its components into the design of a chassis component reduces vertical integration. For an automotive supplier, for example, no subcontractors are required for vibration isolators, and components from different suppliers do not need to be coordinated. Furthermore, the technical limitations of conventional bushings do not apply, so the disadvantages associated with their manufacture and assembly on chassis components do not need to be considered. In particular, all problems associated with connection points are eliminated, since the chassis component according to the invention with integrated vibration isolators is designed homogeneously.

[0025] Therefore, clamping forces, material contacts and aging processes do not need to be taken into account.

[0026] Furthermore, the stiffness properties of vibration isolators can be adjusted to a greater extent than is the case with conventional bushings. These properties can be determined during the development of the actual manufacturing process.

[0027] The method provided for producing the chassis component according to the invention provides that the formation of a vibration isolator by locally changing the material structure of the chassis component is integrated into the manufacturing process of the chassis component. The manufacturing process for producing the chassis component also includes steps for producing one or more isolators. These steps can include the aforementioned production of locally softer and / or thinner regions. The production of these local regions can take place within a continuous manufacturing process so that the manufacturing process is not interrupted for this purpose. However, the production of the local isolators can also involve local and / or temporary changes, for example to tools, material supply and / or the method for manufacturing the chassis component.

[0028] The invention also encompasses a motor vehicle having at least one chassis component according to an embodiment of the invention, wherein the chassis component is connected to the vehicle body via its at least one vibration isolator. Thus, the actual chassis component can be isolated from the body of a motor vehicle by its at least one vibration isolator, thereby reducing the vibrations transmitted from the chassis component to the body.

[0029] Further advantageous embodiments of the invention are disclosed in the dependent claims and the following description of the figures. Fig. 1A is a schematic plan view of a subframe with an insulating bushing according to the prior art, Fig. 1B is a schematic side view of an insulating bushing according to Fig. 1A, Fig. 2A is a schematic side view of a subframe with a first embodiment of an integrated vibration isolator according to the invention, Fig. 2B is a schematic plan view of a vibration isolator according to Fig. 2A, and Fig. 3 a schematic side view of a subframe with an embodiment of an integrated vibration isolator not according to the invention.

[0030] In the different figures, identical parts are always provided with the same reference symbols, which is why they are usually only described once.

[0031] The schematic top view of the Fig. 1A in the xy plane, a right-hand part of a subframe 10 can be seen, in which two insulating bushings 30 and 31 are provided, as they are known in this form or in other modifications from the prior art. Fig. Figure 1B shows one of these insulating bushings 30 in a side view (zy plane). A subframe 10 is connected to a component of the body 20 via this insulating bushing 30. The insulating bushing 30 absorbs vibrations between these two components to isolate them from each other. For this purpose, the insulating bushing 30, made of rubber and metal, can be pressed into the subframe 10, for example, and connected to the body via a screw 50.

[0032] The schematic top view of the Fig. In contrast, Figure 2B in the xy plane shows a left-hand portion of a subframe 10, into which two vibration isolators 40 and 41 are integrated, as provided by the invention. The arrangement of these vibration isolators 40, 41 and the design of the subframe 10 are to be understood merely as examples and serve only to illustrate the vibration isolators. Such vibration isolators can therefore also be provided in other positions and on differently shaped subframes.

[0033] The integration of the vibration isolators into a chassis component of a motor vehicle can also be carried out in various ways, with a possible embodiment of a vibration isolator 40 being shown in the schematic side view of the Fig. 2A (yz plane). The subframe 10 is made at least partially of a fiber-reinforced plastic, which can be reinforced, for example, with carbon, glass, and / or aramid fibers. Thermosets such as epoxy resin can be used as the plastic matrix.

[0034] In the embodiment of the Fig. 2A and Fig. 2B, an integrated vibration isolator 40 is formed by locally modifying the material structure of the subframe to form a vibration isolator. For this purpose, the material of the subframe 10 can be made thinner and / or softer in this defined area of ​​the vibration isolator. Furthermore, several struts can be formed in the vibration isolator 40 as connecting elements, as shown in the top view of Fig. 2B. Four struts are shown as an example, but any other suitable number of struts can be selected. Fig. 2A shows that outer and inner struts are provided, resulting in a total of eight struts serving as connecting elements between the remaining portion of the subframe 10 and a bolt 50. These eight struts form the vibration isolator 40 and are shown hatched. Outer struts are located on the outer side of the subframe 10, while inner struts are located on the opposite inner side of the subframe 10, which faces the body 20.

[0035] The struts are connected to a component of the body 20 via a screw 50, whereby sleeves 51 and 52 can be inserted between the outer and inner struts or between the inner struts and the body 20. These sleeves 51 and 52 are designed to be stiffer than the struts of the vibration isolator 40 so that they can absorb the clamping forces of the screw connection.

[0036] The struts of the vibration isolator 40 can be straight and flat, but they can also take on any other shape. For example, in the embodiment of the Fig. 2A, the outer struts are bent toward the body, while the inner struts are bent toward the head of the screw 50. On both sides of the subframe, the multiple struts thus form a kind of recess, in the center of which the screw 50 is located. The distance between the outer and inner struts thus decreases toward the central screw connection.

[0037] However, a vibration isolator 40 can also have other shapes by having its connecting struts shaped differently. For example, outer struts can form a depression, while inner struts are flat and straight, or vice versa. Furthermore, strut-shaped connecting elements do not have to be provided; rather, a vibration isolator 40 can also be formed by a continuous surface with a corresponding material structure. Fig.3 shows an embodiment not according to the invention, in which a vibration isolator 40' is designed as a bulbous surface that forms a kind of depression or pot on the outside. The outside is referred to as the side of the subframe 10 that faces away from the body 20.

[0038] This vibration isolator 40' has a material structure that differs from the material structure of the rest of the subframe 10 and is elastic enough to ensure an isolating function. At the same time, this material structure is sufficiently rigid to withstand the clamping forces of a screw 50', which connects the subframe 10 to the body 20. An insert can optionally be used for this purpose.

[0039] The vibration isolators described can also be provided on other components such as handlebars. List of reference symbols: 10 subframes 20 Body 30, 31 Insulating bushing 40, 40', 41 Integrated vibration isolator 50, 50' screw 51, 52 sleeve

Claims

[1] Chassis component (10) for a motor vehicle, which is at least partially made of a fiber-reinforced plastic, wherein at least one vibration isolator (40, 41) is formed in the region of the fiber-reinforced plastic by locally modifying the material structure to form the vibration isolator (40, 41), characterized by in that the vibration isolator (40,41) is formed by means of struts, wherein outer struts are arranged on an outer side of the chassis component (10) and inner struts are arranged on the opposite inner side which faces a body (20), wherein sleeves (51,52) are arranged between outer and inner struts and between inner struts and the body (20). [2] Chassis component (10) according to claim 1, characterized by that the material structure of the chassis component (10) is softer in the region of the at least one vibration isolator (40,41) than in the surroundings of this vibration isolator (40,41). [3] Chassis component (10) according to claim 1 or 2, characterized by that the material structure of the chassis component (10) is thinner in the region of the at least one vibration isolator (40,41) than in the surroundings of this vibration isolator (40,41). [4] Chassis component (10) according to one of the preceding claims, characterized by that the plastic is reinforced with carbon, glass and / or aramid fibers. [5] Chassis component (10) according to one of the preceding claims, characterized by that the chassis component (10) is a subframe. [6] Chassis component (10) according to one of the preceding claims, characterized by that the chassis component is a handlebar. [7] Motor vehicle comprising at least one chassis component (10) according to one of the preceding claims, wherein the chassis component (10) is connected to the vehicle body (20) via its at least one vibration isolator (40, 41). [8] Method for producing a chassis component (10) according to one of the preceding claims 1 to 6, characterized by , that the formation of the vibration isolator (40,41) is integrated into the manufacturing process of the chassis component (10) by a local change in the material structure of the chassis component (10).

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