WO2019224021A1

WO2019224021A1 - Stabilizer bar for a vehicle

Info

Publication number: WO2019224021A1
Application number: PCT/EP2019/062082
Authority: WO
Inventors: Bernhard Spielvogel; Johann LANDAUER
Original assignee: Mubea Carbo Tech Gmbh
Priority date: 2018-05-24
Filing date: 2019-05-10
Publication date: 2019-11-28
Also published as: EP3802171A1

Abstract

The invention is directed to a stabilizer bar (1) for a vehicle comprising a composite member (100) made from a composite material. The composite member (100) has a torsion spring portion (110) having a first end region (111) and a second end region (112). The composite member (100) further has a first arm portion (120) bent away from the first end region (111) of the torsion spring portion (110) and the first arm portion (120) comprising a first end portion (121). The composite member (100) further has a second arm portion (130) bent away from the second end region (112) of the torsion spring portion (110) and the second arm portion (130) comprising a second end portion (131). According to the invention the stabilizer bar comprises at least one reinforcing member (200) made at least partially from a metallic material and which is mechanically interconnected with the composite member (200) and extends along a limited portion of the composite member (100) to locally reinforce the composite member (100).

Description

STABILIZER BAR FOR A VEHICLE

FI ELD OF THE INVENTION

The present invention is directed to a stabilizer bar for a vehicle and to a method for producing such a stabilizer bar.

BACKGROU ND OF THE INVENTION

US 201 3/01 131 75 A1 was published on 09.05.201 3 on behalf of LU HN & PU L- VERMACHER - DITTMANN & NEU HAUS GMBH and shows a stabilizer bar of fiber reinforced plastic composite and a method for its manufacture. The documents dis closes a stabilizer bar in fiber composite construction that is of a monolithic con struction without fiber interruption. The cross section geometry, the wall thickness, and the fiber orientation of the stabilizer bar vary in axial direction and radial direc tion in order to fulfill the reguirements defined by the available construction space and the expected loads. According to said publication the fiber orientation is ad justed axially and radially load-appropriately. The middle section of the stabilizer bar is reinforced with fibers oriented between -P/-35 degrees and -P/-55 degrees relative to the longitudinal axis and the end members that are primarily bending- loaded are reinforced with fibers oriented between +/-20 degrees and +/-40 de- grees relative to the longitudinal axis. In the transitional areas between the middle section and the end members there are transitions between these fiber orientations relatively to the longitudinal axis.

US 201 5/01 15560 A1 was published on 30.04.201 5 on behalf of Dr. Ing. h.c. F. Porsche Aktiengesellschaft and shows a fiber composite component and method for producing a fiber composite component. The document discloses a fiber com posite torsion-bar stabilizer for a motor vehicle that has an elongate main body which has a plurality of tubular layers which are each formed from fibrous threads and casting resin. The tubular layers are arranged in one another in the radial direc tion of the main body, and the fibrous threads of the different layers are each ori- ented at different angles relative to a longitudinal direction of the main body. Ac cording to said document the fibrous threads are braided together in order to form the different layers.

WO 2014/161 791 A1 was published on 09.1 0.201 4 on behalf of Mubea Carbo Tech GmbH (the same applicant as the application at hand) and discloses a hybrid spring device that comprises an outer tubular shell. The hybrid spring device further comprises an inner part enclosed in the outer tubular shell which comprises a fiber reinforced plastic material. According to the document the outer tubular shell is de signed as self-supporting part made from a metallic material. The document dis closes that a spring device may have the shape of a torsion rod (stabilizer) of an automotive torsion spring axle. SU MMARY OF THE INVENTION

Stabilizer bars are in inter alia used in order to reduce body roll of vehicles during cornering. Thus, they improve steering performance and hence travelling comfort and driving safety. Most stabilizer bars have essentially a U-shape comprising a first and a second arm interconnected by a back that acts as a torsional spring. However, in practice many stabilizer bars are not perfectly planar but have a spatially highly curved shape in order to avoid other components of a vehicle, such as the chassis or exhaust system. As a conseguence, stress and strain distribution becomes complex and therefore typically relatively large bars (respectively tubes with high wall thickness) have to be used in order to prevent local supercritical stress and strain.

Another major problem known for modern vehicles (in particularly cars) is that for several years their curb weight has been increasing constantly mainly due to in creasing reguirements regarding safety and passenger convenience as well as power sources (e.g. batteries of all-electric cars). In order to counteract this ten dency weight saving becomes necessary, which may be obtained by introducing concepts of lightweight materials and/or design for conventional components of vehicles.

In order to solve at least one of the herein mentioned problems, according to the present invention a stabilizer bar for a vehicle typically comprises a composite mem ber made from a composite material which has a torsion spring portion comprising a first end region and a second end region. The stabilizer bar typically also com prises a first arm portion bent away from the first end region of the torsion spring portion and comprising a first end portion. The stabilizer bar typically also com prises a second arm portion bent away from the second end region of the torsion spring portion and comprising a second end portion. According to the invention at least one reinforcing member made at least partially from a metallic material is me chanically interconnected with the composite member and extends along a limited portion of the composite member to locally reinforce the composite member.

According to the invention a stabilizer bar can be obtained which has a low and equally distributed weight if compared to conventional stabilizer bars made e.g. from spring steel. As well, a stabilizer bar having a specified spring characteristics can be easily obtained. In addition a stabilizer bar according to the present inven tion is less prone to local thermal loading (e.g. due to the exhaust system) due to the combination of composite and metallic material. The same holds true for local mechanical damage due to mechanical impacts (e.g. road stones etc. ) if compared to stabilizer bars made solely from composite materials.

In addition, a stabilizer bar according to the invention can be produced using highly automated methods as well as a high degree of material utilization can be obtained as will be explained in more detail below. In addition, the reinforcing members can be integrated in the manufacturing process and thus no additional joining (pro cesses) in post-processing is needed. All this allows to obtain economical stabilizer bars. As well, in particular if compared to stabilizer bars made solely from compo site materials, fatigue behavior can be improved and service strength be increased without high additional weight.

In a variation of the invention the reinforcing member locally increases the torsional stiffness and/or bending stiffness of the composite member. Hence local and global stiffness of the stabilizer bar, respectively mechanical performance can be adjusted to meet certain reguirements e.g. regarding mechanical behavior and weight.

Particularly good results may be obtained if the composite member is at least par- tially made from a fiber-reinforced plastic. Different types of fiber-reinforced plas tics may be applied, such as layers of braided fibers, woven fibers, wound fibers or combinations thereof. In particular use of long fibers may be advantageous. Vari ous types of fibers may be used, such as carbon fibers, glass fibers, aramid fibers, mineral fibers and combinations thereof. However, the invention is not limited to these types of fibers, respectively fabrics.

Good results may be obtained if the composite member comprises multiple layers of reinforcing fibers, in particular if layers of reinforcing fibers are arranged super imposed and essentially concentrically about the center axis of the stabilizer bar or composite member. A highly versatile type of stabilizer may be obtained if between 6 and 8 layers of fibers are superimposed. In a variation of a stabilizer bar according to the invention, a first group of fibers having a first Young's modulus is arranged at a first distance from the center axis of the stabilizer bar and a second group of fibers having a second Young's modulus is arranged at a second distance from the center axis of the stabilizer bar, the sec- ond distance being greater than the first distance and the first Young's modulus being greater than the second Young's modulus. Thus, a particularly even stress and strain distribution can be obtained in the composite member. This leads to a more efficient use of the reinforcing fibers. Conseguently the total volume and con- seguently also total weight of the composite member can be minimized. The first and the second group of fibers may be layers of reinforcing fibers, in par ticular layers of reinforcing fibers arranged essentially concentrically about the cen ter axis of the stabilizer bar (or composite member). Particularly good results may be obtained if at least some of the layers of fibers are braided layers of fibers. Hence, the composite member may at least partially be produced using over-braiding lay- ers of fibers.

Particularly good results may be obtained if the first Young's modulus is greater than about 250 GPa (gigapascal or N/mm²) and the second Young's modulus is less than about 250 GPa (gigapascal or N/mm²). It turned out that in particular (but not only) for composite members comprising superimposed layers of braided reinforcing fibers, the herein described arrangement/composition of reinforcing fi bers having different Young's modules typically allows to reduce the total number of superimposed layers of reinforcing fibers. As in particular over-braiding of fibers is a relatively time-consuming and expensive process, such a composition of differ ent types of fibers does not only allow to obtain more lightweight stabilizer bars but also to maintain or even reduce the total manufacturing costs, although fibers with a higher Young's modulus typically are more expensive than such with a lower Young's modulus.

The at least one reinforcing member may e.g. be made from a steel (particularly a spring steel), an aluminum, a titanium, a magnesium or combinations thereof. Within the context of the present invention, steel, aluminum, magnesium and tita nium should be understood as meaning also their alloys. A variation of a stabilizer bar that has a particularly high torsional stiffness at a low total weight may be obtained if the at least one reinforcing member comprises a tubular shell. It may comprise multiple tubular shells that may be mechanically in terconnected with each other. Particularly high torsional stiffness may be obtained if at least a portion of the tubular shell has an essentially circular cross-section. Al- ternatively or in addition at least a portion of the tubular shell may have an essen tially ellipsoidal cross-section. Thus the bending properties of the stabilizer bar may be improved as well as the transfer of torsional load between the composite mem ber and the reinforcing member can be increased. Alternatively or in addition at least a portion of the tubular shell may have an essentially polygonal cross-section. The cross-section may e.g. be rectangular, pentagonal or hexagonal. However, also other types of cross sections may be used. In a variation of the present invention, the reinforcing member comprises a plate, which may be curved in at least one direction. Hence, the present invention is not limited to reinforcing members having a tubular shapes.

According to a variation of the invention, the wall thickness of at least a portion of the tubular shell may vary along the central axis of the stabilizer bar and/or in cir cumferential direction of the tubular shell. Thus, stress and strain distribution in the stabilizer bar can easily be optimized. A variation of a stabilizer bar having a partic ularly high durability and can produced particularly economically may be obtained if tailor rolled tubes (TRT) are applied. According to a variation of the invention the at least one reinforcing member is ar ranged in the transition area between first end region and the first arm portion and/or in the transition area between second end region and the second arm por tion. Thus, highly durable stabilizer bars may be obtained.

According to a variation of the invention the composite member comprises at least one layer of glass fibers arranged adjacent to the reinforcing member. Hence the two member can be electrochemically decoupled and thus galvanic corrosion can be prevented.

In a variation of the invention at least a part of the at least one reinforcing member is arranged on an outer surface of the composite member. Thus, certain parts of the stabilizer bar can be efficiently be protected against mechanical impacts, as well as torsional stiffness and bending stiffness can be increased particularly efficiently with only relatively minor additional weight.

Alternatively or in addition, at least a part of the at least one reinforcing member is arranged embedded in the composite member, respectively embedded in compo- site material, such as fiber-reinforced plastic. Such a variation of a stabilizer bar ac cording to the invention may be particularly resistant to corrosion.

Alternatively or in addition at least part of the at least one reinforcing member may be arranged on an inner surface of the composite member. The composite member may have an inner hollow channel that extends at least partially along the stabilizer bar. Such an inner channel may be void (respectively be filled with gas) or may also at least partially be filled, such as by a solid foam.

For some applications, at least a part of the reinforcing member may have a closed profile. For some applications, at least a part of the reinforcing member may have an open profile. In a variation of the invention, the at least one reinforcing member comprises at least one resilient portion. The resilient portion may comprise at least one chamfer and/or at least one opening (respectively perforation) and/or at least one incision and/or a local variation of the material. Thus the resilient region may e.g. be made from a completely different material or if may be from essentially the same material, but may e.g. have a different micro-structure such as induced by local soft anneal ing. A resilient region may be advantageous in order to prevent stress concentration in the composite member, as will be explained in more detail below.

In a variation of the invention, the resilient portion may be located at a boundary region of the reinforcing member. Thus, load paths in the stabilizer bar can be op timized and potentially super-critical stress concentration in the stabilizer bar at the boundary regions of the reinforcing members can be prevented.

Good results may be obtained if the at least one reinforcing member comprises at least one chamfer and/or rounding. For some applications, the chamfer may have an angle of between 1 0° and 45° (degrees).

In a variation of the invention, at least one transition means is arranged at the in terstitial region between the boundary region of the reinforcing member and the composite member to reduce local stress concentration. Such a transition means may comprise e.g. a beading of adhesive and/or a local reinforcement e.g. made from a fiber-reinforced plastic with at least one layer of reinforcing fibers. In a var iation of the invention, the transition means may be arranged on an outer surface and/or an inner surface of the composite member. The transition means may be an integral part of the composite member, as will be explained in more detail below.

In a variation of the invention the at least one reinforcing member comprises at least one opening. It may also comprise multiple openings that may also be regarded as a perforation. Such at least one opening may be used in order to reduce the total weight of the stabilizer bar. As well, the at least one opening may be used in order to obtain a desired stress and strain distribution in the reinforcing member and/or to control the stiffness of the reinforcing member. Alternatively or in addition, the at least one reinforcing member may comprise at least one incision. Alternatively or in addition, it may also comprise a groove and/or a thin area, respectively an area with decreased wall thickness. Thus, not only the mechanical characteristics can be designed but also total weight of the stabilizer bar can be reduced.

The at least one reinforcing member may comprise several different wall thick nesses. Thus, the wall thickness may be adapted to the distribution of forces. In a variation of the invention, such an at least one reinforcing member may be obtained using tailor rolled tubes (aka TRT).

In a variation of the invention, at least a portion of the reinforcing member is coated with an adhesion promoter (e.g. coupling agent and/or primer) to increase the chemical and/or mechanical interconnection with the composite member. Alter- natively or in addition at least a portion of the reinforcing member may be rough ened and/or threatened with electrophoretic deposition which may also be used in order to prevent electrochemical corrosion.

Alternatively or in addition, at least a portion of the reinforcing member may be arranged to prevent or at least decrease mechanical and/or chemical interconnec- tion with the composite member. As such, it e.g. may be coated with a nonstick agent. Thus, distribution of forces may be controlled more efficiently. In a variation of the invention at least a portion of the reinforcing member is coated with an anti-corrosive material. Thus, e.g. salt corrosion may be prevented effi ciently. The at least one reinforcing member may be at least partially coated by a polymeric material, in particular with a non-conducting polymeric material. Thus a particularly good protection against corrosion, in particular electrochemical corro sion phenomena can be obtained. Alternatively or in addition to a polymeric mate rial, the coating may also be made from another material suited to obtain at least one of the effects stated herein - e.g. a ceramic or a glass. Good results may be obtained if the at least one reinforcing member is fully coated by a polymeric ma- terial. A coating with a polymeric material may also help to prevent intrusion and accumulation of corrosion-enhancing substances in the region between the com posite member and the reinforcing member.

In a variation of the invention, at least a portion of the outer surface of the stabilizer bar are coated with a protective coating, e.g. an anti-corrosive material. Thus, a stabilizer bar that is highly durable even under very difficult and demanding envi ronmental conditions may be obtained. Good results may be obtained, if essentially the complete outer surface of a stabilizer bar is coated with a protective coating, e.g. an anti-corrosive material. A protective coating may also include or be a heat shielding coating, such as a ceramic. In a variation of the invention the at least one reinforcing member constitute at least part of a core structure (e.g. braiding core structure) of the stabilizer bar that may be wound by fibers of the composite member. Thus, particularly economical pro- duction of stabilizer bars may be obtained. In a variation of the invention, the sta bilizer bar may comprise a core structure that may comprise a foam material, such as a solid braiding foam. The core structure may be at least partially be removed from the stabilizer bar (e.g. by dissolving) after production of the composite mem- ber in order to reduce total weight of the stabilizer bar.

In a variation of the invention, the at least one reinforcing member may comprise a mounting portion that may be configured to be interconnected with a stabilizer mounting bush of a vehicle. Hence a highly durable mounting of the stabilizer bar can be obtained. Alternatively or in addition, the at least one reinforcing member may also be used in order to mount other types of components, such as auxiliary components like sensors. Thus, such components can easily and very reliably be interconnected with the stabilizer bar without negatively affecting the structural in tegrity of the stabilizer bar - respectively the layup of the composite member.

The present invention is further directed to providing a method for producing of a stabilizer bar. Such a method typically comprises the method steps of: a) providing a core structure, which may e.g. be a braiding core; b) adding at least one layer of reinforcing fibers having a predefined orientation on the core structure until a com posite member with a specified layup (layer structure) is obtained; c) providing at least one reinforcing member made at least partially from a metallic material; d) arranging the at least one reinforcing member such that it is at a specified location of the stabilizer bar to be produced and adjacent to at least one layer of reinforcing fibers to be laid; e) interconnecting the composite member with the at least one reinforcing member. In a variation of the method according to the present invention, method step d) is performed prior to method step b). Thus, a variation of a stabilizer bar in which at least one reinforcing member is arranged adjacent to a central canal may be ob tained. Such a central canal may be void or may at least partially be filled with e.g. a core structure, such as a solid foam and/or a resin.

In a variation of the method according to the present invention method step d) is performed after method step b). Thus, a variation of a stabilizer bar in which at least one reinforcing member is at least partially embedded in the composite mem ber and/or is arranged at least partially on an outer surface of the composite mem- ber can be obtained.

In a variation of the method according to the present invention, for at least one first reinforcing member step d) is performed prior to method step b) and for at least one second reinforcing member method step d) is performed after method step b). Hence, for variations of a stabilizer bar comprising multiple reinforcing members said reinforcing members may be arranged at different relative positions with re spect to the composite member using such a variation of the method according to the present invention.

In a variation of the method according to the present invention at least one addi tional reinforcing member made at least partially from a metallic material is ar- ranged at the same time and/or subseguently to method step b). In a variation of the method according to the present invention the core structure provided in method step a) comprises at least one reinforcing member made at least partially from a metallic material. Thus, variations of a stabilizer bar having at least one reinforcing member arranged in an inner channel can be obtained easily. As well by such integration of the reinforcing member in the production process of the core structure, no additional joining process is necessary in the production of a stabilizer bar.

A variation of the method according to the present invention further comprises the method step of removing at least part of the core structure after method step b). Part of the core structure may be removed after hardening of the composite mem ber.

In a variation of the method according to the present invention the layers of fibers are applied using a winding process and/or a braiding process. This makes an eco nomical production possible. A particularly economical production possible if the composite member and the at least one reinforcing member are interconnected using a resin transfer molding process (RTM).

In a variation of the method according to the present invention the composite member is hardened and subseguently at least one reinforcing member made at least partially from a metallic material is applied on an outer surface of the hardened composite member. Thus, a large variety of different variations of stabilizer bars suited for different applications (respectively expected operating loads) can be ob tained using the same type of composite member, allowing highly economical pro duction. A particularly durable variation of stabilizer bar may be obtained using a variation of the method according to the present invention according to which at least one additional layer of fibers is applied on the at least one reinforcing member applied on the outer surface of the hardened composite member.

BRI EF DESCRIPTION OF THE DRAWI NGS

The herein described invention will be more fully understood from the detailed de- scription of the given herein below and the accompanying drawings, which should not be considered as limiting to the invention described in the appended claims.

Fig. 1 schematically shows a variation of a stabilizer bar in a perspective view from above;

Fig. 2 schematically shows the stabilizer bar of Fig. 1 in a top view; Fig. 3 schematically shows cross-section AA of Fig. 2;

Fig. 4 schematically shows a cross-section of a second variation of a stabilizer bar according to the invention; Fig. 5 schematically shows a cross-section of a third variation of a stabilizer bar according to the invention;

Fig. 6 schematically shows a cross-section of a fourth variation of a stabilizer bar according to the invention; Fig. 7 schematically shows a cross-section (parallel to center axis Ay) of a fifth variation of a stabilizer bar according to the invention;

Fig. 8A shows Detail D of Fig. 7;

Fig. 8B shows Detail D according to Fig. 7 of a sixth variation of a stabilizer bar according to the invention; Fig. 9 schematically shows a cross-section (parallel to center axis Ay) of a sev enth variation of a stabilizer bar according to the invention;

Fig. 1 0 shows Detail E of Fig. 9;

Fig. 1 1 schematically shows a cross-section (parallel to center axis Ay) of a sev enth variation of a stabilizer bar according to the invention; Fig. 1 2 schematically shows part of an eight variation of a stabilizer bar accord ing to the present invention in a perspective view from above;

Fig. 1 3 schematically shows a variation of a reinforcing member according; Fig. 1 4 schematically shows another variation of a reinforcing member accord ing;

Fig. 1 5 schematically shows another variation of a reinforcing member accord ing; Fig. 1 6 schematically shows another variation of a reinforcing member accord ing;

Fig- 1 to Fig. 3 schematically show a first variation of a stabilizer bar 1 for a vehicle according to the present invention. The stabilizer bar 1 comprises a composite member 1 00 made from a composite material which in this variation is a fiber-re- inforced plastic. The composite member 1 00 comprises a torsion spring portion 1 1 0 which has a first end region 1 1 1 and a second end region 1 1 2. The composite member 1 00 further comprises a first arm portion 1 20 bent away from the first end region 1 1 1 of the torsion spring portion 1 1 0, the first arm portion 1 20 com prising a first end portion 1 21 at which a connecting 300 to be interconnected e.g. to a wheel suspension is arranged. The composite member 1 00 further comprises a second arm portion 1 30 bent away from the second end region 1 1 2 of the tor sion spring portion 1 1 0, the second arm portion 1 30 comprising a second end portion 1 31 . Within the context of the present invention the composite member may be an integral structure or may be made from multiple components. The vari- ation of a stabilizer bar 1 00 schematically shown in Fig .1 to Fig. 3 further com prises two tubular reinforcing members 200 that are made from a spring steel and that are mechanically interconnected with the composite member 200 and both extend along limited portions of the composite member 1 00 to locally reinforce the composite member 1 00. In the variation of a stabilizer bar shown Fig .1 to Fig. 3, the two reinforcing members 200 are arranged in the transition area between first end region 1 1 1 and the first arm portion 1 20 respectively in the transition area be- tween second end region 1 1 2 and the second arm portion 1 30. They are config ured and arranged in order to locally increase the torsional stiffness and bending stiffness of the composite member 1 00. Both reinforcing members 200 are ar ranged on an outer surface 1 40 of the composite member 1 00, as illustrated in Fig. 3. Thus the total torsional stiffness of the stabilizer bar 1 can increased particularly efficiently.

Fig. 4 schematically shows a variation of the stabilizer bar 1 where a reinforcing member 200 is arranged on an inner surface 1 50 of the composite member 1 00. Such a variation of a stabilizer bar may be particularly durable as corrosion of the metallic reinforcing member 200 can be minimized. This variation further com- prises an inner channel 1 60 that is void, respectively filled with a gas and conse- guently has a particularly low weight.

Fig. 5 schematically shows a variation of a stabilizer bar 1 similar to the variation shown in Fig. 4. In contrast to the variation shown in Fig. 4, the inner channel 1 60 is filled with a core structure 400 made from a solid foam. Such a variation can be produced particularly economically. Fig. 6 schematically shows a variation of a stabilizer bar 1 in which the reinforcing member 200 is arranged embedded in the composite member 1 00 and hence is particularly well protected against corrosion.

Fig. 7 schematically shows a cross-sectional view parallel to a center axis Ay of a portion of a variation of a stabilizer bar 1 . The stabilizer bar 1 comprises a reinforc ing member 200 that has a tubular shell 21 0 which has an essentially circular cross section and is arranged on an outer surface 1 40 of a composite member 1 00 hav ing a tubular shape as well. As schematically illustrated in Fig. 8A showing Detail D of Fig. 7, the reinforcing member 200 comprises a resilient portion 220 located at a boundary region of the reinforcing member 200. A certain distance apart from the boundary region, the reinforcing member 200 has a certain wall thickness D2 which decreases at the resilient portion 220 due to a chamfer 221 with an angle a (alpha). The composite member 1 00 has a wall thickness D 1 which is constant at this region of the stabilizer bar 1 . Due to the decrease of wall thickness D 1 , super- critical stress concentration in the composite member 1 00 can be prevented.

Fig. 8B schematically shows a detail analogous to detail D of Fig. 7 of another var iation of a stabilizer bar 1 in which a first and a second transition means 500, 501 are arranged at the interstitial region between the boundary region of the reinforc ing member 200 and the composite member 1 00 to reduce local stress concentra- tion. The first transition means 500 comprises an annular beading of an adhesive agent that is arranged on the outer surface 1 40 of the composite member 1 00 and extends to a resilient portion 220 of the reinforcing member 1 00. The second tran sition means 501 is arranged on the inner surface of the composite member 1 00 and comprises a fiber-reinforced plastic with multiple layers of reinforcing fibers. The second reinforcing means 501 is an integral part of the composite member 200.

Fig. 9 and Fig. 10 schematically show a variation of a stabilizer bar 1 according to the present invention in which a reinforcing member 200 is embedded in the com posite member 1 00. In the variation shown, the reinforcing member 200 also com prises a resilient portion 220 having a chamfer 221 that is designed in order to prevent supercritical stress concentration in the surrounding composite member 1 00, including both supercritical stress in the fibers as well as inter-laminar stress that else may cause delamination of the composite member 1 00.

Fig. 1 1 schematically shows a variation of a stabilizer bar 1 according to the present invention in which a first reinforcing member 200 arranged on an outer surface 1 40 of the in the composite member 1 00 and a second reinforcing member 201 arranged on an inner surface 1 50 of the in the composite member 1 00. In the var iation shown, the first reinforcing member 200 comprises a mounting portion (224) configured to be interconnected with a stabilizer mounting bush (not shown) of a vehicle. The variation of a mounting portion 224 shown in Fig. 1 1 comprises a cir- cumferential groove. Furthermore the wall thickness D2 of the first reinforcing member 200 varies along the center axis Ay of the stabilizer bar 1 in order to obtain a specified stress and strain distribution and hence prevent supercritical stress and strain as well as mechanical reaction to applied load. Fig. 1 2 schematically shows a variation of a stabilizer bar 1 according to the present invention in which a first reinforcing member 200 is formed like a tubular shell, however is not completely rotationally symmetric but has angularly cut ends in or der to obtain a certain stress and strain distribution in the stabilizer bar 1 . Fig. 1 3 schematically shows a variation of a reinforcing member 200 that com prises a tubular shell 21 0 which has at its two boundary regions two resilient por tions 220 comprising multiple openings 222 forming a perforation with a lower torsional stiffness. If arranged at a composite member (not shown) the openings at the same time allow intrusion of resin of the composite member and hence to increase local load transfer between the composite member and the reinforcing member 200 having at this region a lower torsional stiffness). As at the same time torsional stiffness of the reinforcing member 200 is reduced in these resilient por tions 220, stress and strain distribution in the composite member can be optimized very efficiently. Fig. 14 schematically shows a variation of a reinforcing member 200 that com prises a tubular shell 21 0 which has at its two boundary regions two resilient por tions 220 comprising multiple incisions 223 evenly distributed circumferentially about the tubular shell 21 0. In other variations a non -even distribution may be cho sen to obtain a certain stress distribution when interconnected with a composite member. Fig. 1 5 schematically shows another variation of a reinforcing member 200 that comprises a tubular shell 21 0 having three resilient portions 220 embodied in dif ferent ways. A first resilient portion 220 arranged at a first boundary region of the reinforcing member 200 comprises multiple openings/bores that form a perfora- tion 222. A second resilient portion 220 arranged at a second boundary region of the reinforcing member 200 comprises a chamfer 221 and a third resilient region arranged in between comprises an annealed portion 225 which has been annealed in order to obtain a softer microstructure.

Fig. 16 schematically shows a reinforcing member 200 which comprises a tubular shell 21 0 that has an essentially open profile due to a longitudinal incision 223. Such a variation of a reinforcing member 200 will typically have a lower torsional stiffness than variations with essentially closed profiles (as described above) which may help to obtain a specified stress and strain distribution in a stabilizer bar (not shown) as well as it may be arranged at a composite member 1 00 after at least part of the resin of this composite member has already hardened.

REFERENCE NUMERALS

I Stabilizer bar (torsion bar) 25 400 Core structure

100 Composite member 500 First transition means

110 Torsion spring portion 501 Second transition means 111 First end region Ay Center axis

I I 2 Second end region D1 Wall thickness of the composite

120 First arm portion 30 member

121 First end portion D2 Wall thickness of the reinforc 130 Second arm portion ing member

131 Second end portion

140 Outer surface of the composite

member

150 Inner surface of the composite

member

160 Innerchannel

200, 201 Reinforcing member

210 Tubular shell

220 Resilient portion

221 Chamfer

222 Opening, perforation

223 Incision

224 Mounting portion

225 Annealed portion

300 Connecting means

Claims

1. A stabilizer bar (1 ) for a vehicle comprising a) a composite member (100) made from a composite material, having i. a torsion spring portion (110) having a first end region (111) and a second end region (112) and ii. a first arm portion (120) bent away from the first end region ( 111 ) of the torsion spring portion (110) and

1. the first arm portion ( 120) comprising a first end por tion (121); and iii. a second arm portion (130) bent away from the second end region ( 112) of the torsion spring portion (110) and

1. the second arm portion (130) comprising a second end portion (131); and iv. at least one reinforcing member (200) made at least partially from a metallic material and that is mechanically intercon nected with the composite member (200) and extends along a limited portion of the composite member (100) to locally reinforce the composite member ( 100).

2. The stabilizer bar ( 1 ) according to claim 1 , wherein the reinforcing member (200) locally increases the torsional stiffness and/or bending stiffness of the composite member ( 1 00).

3. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein the composite member ( 1 00) is at least partially made from a fiber-reinforced plastic.

4. The stabilizer bar ( 1 ) according to claim 3, wherein the composite member ( 1 00) comprises multiple layers of reinforcing fibers.

5. The stabilizer bar ( 1 ) according to claim 4, wherein the layers of reinforcing fibers are arranged superimposed and essentially concentrically about the center axis (Ay) of the stabilizer bar ( 1 ).

6. The stabilizer bar ( 1 ) according to any one of claims 3 to 5, wherein a first group of fibers having a first Young's modulus is arranged at a first distance from the center axis (Ay) of the stabilizer bar ( 1 ) and a second group of fibers having a second Young's modulus is arranged at a second distance from the center axis (Ay) of the stabilizer bar ( 1 ), the second distance being greater than the first distance and the first Young's modulus being greater than the second Young's modulus.

7. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein the at least one reinforcing member (200) comprises a tubular shell (21 0).

8. The stabilizer bar ( 1 ) according to claim 7, wherein at least a portion of the tubular shell ( 21 0) has an essentially circular cross-section.

9. The stabilizer bar ( 1 ) according to any one of claims 7 and 8, wherein at least a portion of the tubular shell (21 0) has an essentially ellipsoidal cross-section.

10. The stabilizer bar ( 1 ) according to any one of claims 7 to 9, wherein at least a portion of the tubular shell (21 0) has an essentially polygonal cross-section.

1 1. The stabilizer bar ( 1 ) according to any one of claims 7 to1 0, wherein the wall thickness (D2) of at least a portion of the tubular shell (21 0) varies along the central axis of the stabilizer bar ( 1 ) and/or in circumferential direction of the tubular shell ( 21 0).

12. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein the at least one reinforcing member (200) is arranged in the transition area between first end region ( 1 1 1 ) and the first arm portion ( 1 20) and/or in the transition area between second end region ( 1 1 2) and the second arm portion ( 1 30).

13. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein at least a part of the at least one reinforcing member (200) is arranged on an outer surface ( 1 40) of the composite member ( 1 00).

14. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein at least a part of the at least one reinforcing member (200) is arranged em bedded in the composite member ( 1 00).

15. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein at least part of the at least one reinforcing member (200) is arranged on an inner surface ( 1 50) of the composite member ( 1 00).

16. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein the at least one reinforcing member ( 200) comprises at least one resilient portion (220).

17. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein at least a portion of the reinforcing member (200) is coated with an adhesion promoter increasing the chemical and/or mechanical interconnection with the composite member.

18. The stabilizer bar ( 1 ) according to any one of the preceding claims, wherein the at least one reinforcing member (200) constitutes at least part of a core structure (400) of the stabilizer bar ( 1 ) that is wound by fibers of the com posite member ( 1 00).

19. A method for producing of a stabilizer bar ( 1 ) comprising the method steps of: a) providing a core structure; b) adding at least one layer of reinforcing fibers having a predefined ori entation on the core structure until a composite member ( 1 00) with a specified layup is obtained; c) providing at least one reinforcing member (200) made at least par tially from a metallic material; d) arranging the at least one reinforcing member (200) such that it is at a specified location of the stabilizer bar to be produced and adjacent to at least one layer of reinforcing fibers to be laid; e) interconnecting the composite member ( 1 00) with the at least one reinforcing member (200).

20. The method of claim 1 9, wherein method step d) is performed prior to method step b).

21. The method of claim 1 9, wherein method step d) is performed after method step b).

22. The method of claim 21 , wherein at least one additional reinforcing member made from a metallic material is arranged at the same time and/or subse- guently to method step b).

23. The method according to any one of claims 1 9 to 22, wherein the core struc ture provided in method step a) comprises at least one reinforcing member (200) made at least partially from a metallic material.

24. The method according to any one of claims 1 9 to 23, comprising the method step of removing at least part of the core structure after method step b) .

25. The method according to any one of claims 1 9 to 24, wherein the layers are applied using a winding process and/or a braiding process.

26. The method according to any one of claims 1 9 to 25, wherein the composite member is hardened and subseguently at least one reinforcing member made at least partially from a metallic material is applied on an outer surface of the hardened composite member.