Wheel suspension for a vehicle front axle

Abstract

Wheel suspension for a front axle of a two-track vehicle, with a wheel carrier (1) carrying a front wheel (3) which is articulated to a vehicle body via a link assembly, wherein the link assembly has at least one link (6) which is articulated to the wheel carrier (1) at a wheel carrier-side bearing point (11) via a joint (29), wherein the wheel carrier (1) is designed with a crash element (27) which, during normal operation, assumes a non-use position (N), in which the crash element (27) is arranged radially inside a rim (17) of the front wheel (3) and with a clearance (f) spaced from an inner circumference (51) of the rim (17), wherein in the event of a frontal collision, the rim (17) of the front wheel (3) facing the crash is deformed and comes into pressure contact with the crash element (27) of the wheel carrier (1), characterized in that the crash element (27) has a wedge-shaped detachment contour (41),and that the crash element (27) is adjustable in the event of a frontal collision with respect to the wheel carrier (1) by a crash path (Δx), specifically up to an operative position (W) in which the wedge-shaped release contour (41) is wedged between the wheel carrier (1) and the joint (29) in such a way that the crash element (27) has a release force (F, L ) against the joint (29) in order to release the joint connection between the link (6) and the wheel carrier (1).

Description

The invention relates to a wheel suspension for a front axle of a two-track vehicle according to the preamble of claim 1.In a so-called small overlap crash test, the collision with the collision obstacle takes place with a small lateral overlap. The impact forces are therefore introduced directly into the front wheel facing the crash in the vehicle longitudinal direction at least partially outside the front longitudinal member of the vehicle. The wheel rim of the front wheel is displaced rearward in the vehicle front-rear direction toward the vehicle occupant's foot space. This creates the risk of a crash-induced turning of the front wheel together with an intrusion into the vehicle occupant's foot space.From DE 10 2015 112 509 A1, a wheel suspension of the generic type is known, which has a wheel carrier carrying a front wheel, which is linked to a vehicle body via a linkage. The link assembly has at least one link which is articulated on the wheel carrier at a bearing point on the wheel carrier side via a joint. The wheel carrier is also designed with a crash element, with which a crash-induced turning-in of the front wheel is prevented in the event of a frontal collision. The crash element is realized as a deflection support. In normal operation, this assumes a non-use position in which the deflection support is arranged radially inside a front wheel rim and with a clearance from a rim inner periphery. In the event of a frontal collision, the rim of the front wheel facing the crash is deformed and comes into pressure contact with the deflection support formed on the wheel carrier.The following mechanism of action is achieved with the deflection support known from DE 10 2015 112 509 A1 in the event of a vehicle collision: the deforming wheel rim thus comes into pressure contact with the deflection support formed on the wheel carrier, namely, with the establishment of a clamping action between the wheel carrier and the inner periphery of the deforming rim. The deflection support clamped between the wheel carrier and the rim inner periphery prevents a crash-induced turning-in of the vehicle wheel. The same mechanism of action is also used in DE 10 2013 214 719 A1: Consequently, a component-rigid dome is formed on the wheel carrier. In the event of a frontal collision, the dome comes into contact with the deforming rim in order to prevent a crash-induced turning-in of the vehicle wheel. Similar action mechanisms are also known from DE 10 2014 003 453 B3 and from DE 10 2013 012 273 A1. DE 10 2012 204 032 A1 discloses a front wheel suspension on a two-track vehicle. DE 10 2013 207 144 A1 discloses a front wheel suspension for a two-track vehicle and a steering handle for such a front wheel suspension and a two-track vehicle with such a front wheel suspension.The object of the invention is to provide a wheel suspension with a crash element which, in the event of a frontal collision, enables an easily realizable operating mechanism which is different compared to the above prior art and by means of which the wheel carrier is at least partially released from the steering assembly in the event of a collision.The object is achieved by the features of claim 1. Preferred developments of the invention are disclosed in the dependent claims.In contrast to the action mechanisms known from the prior art, the crash element according to the invention no longer generates a clamping action between the wheel carrier and the rim inner periphery.Rather, the crash element is designed such that it acts on the joint between the steering arm and the wheel carrier in the event of a vehicle collision in order to release the articulated connection. The crash element has a wedge-shaped detachment contour according to the characterizing part of claim 1. In the event of a frontal collision, the crash element is adjusted with respect to the wheel carrier by a crash path, namely into an operative position in which the wedge-shaped detachment contour is keyed between the wheel carrier and the joint. In this way, the crash element exerts a releasing force on the joint counter to the joint joining or mounting direction in order to release the joint connection between the steering arm and the wheel carrier. In the event of a collision, it is thus possible-depending on the kinematics of the axis and position of the released steering arm-to rotate or to rotate the wheel outside the wheel arch.It is preferred if the crash element is formed directly on the wheel carrier via a support section that is elastically or plastically deformable in the event of a crash. In the event of a frontal collision, the crash element can therefore be adjusted with respect to the wheel carrier by the crash path, namely by the action of the deforming rim, as far as the operative position in which the crash element presses against the joint with the release force.In a technical implementation, the joint can have a joint housing assigned to a first connection partner, into which a joint part assigned to a second connection partner is inserted in a joining direction. With regard to a simple detachment process, it is preferred if, in the event of a frontal collision, the crash element presses directly onto the joint part with the detachment force, namely preferably in a direction opposite to the joining direction (or pin extension direction), whereby the required magnitude of the detachment force can be kept low.In a particularly preferred embodiment variant, the joint can be a ball joint which has as the joint part a ball stud which is inserted into a joint housing corresponding thereto. The joint housing can be fastened directly to the wheel carrier, for example, while the ball stud can be fastened directly to the steering rod.Such a ball joint can be loaded equally in all directions of the X-Y plane and also experiences strong loads during driving operation and in special events, which is why a lateral detachment or predetermined breaking points are not successful. In the vehicle vertical direction z, however, the ball joint is less resilient by a multiple, because there are only a few load cases with such a loading direction in normal operation. Ball joints are often incorporated in chassis control arms in a releasable or non-releasable manner. Since the forces in a rod link are transmitted almost completely in the link direction, ball studs of ball joints are usually fixed normal to this operating direction, for example by rolling in.With regard to a satisfactory mode of operation, the crash element can have an in particular wedge-shaped detachment contour which interacts with a mating contour of the joint. In the event of a frontal collision, the detachment contour of the crash element can come into contact with the joint-side mating contour, as a result of which a detachment force is built up, is released by means of the joint connection. In a concrete installation situation, the joining direction or a central axis of the ball joint is oriented at right angles to a (substantially horizontal) link rod direction. In this case, the joining direction, which is coaxial with a ball joint axis, runs in the vehicle vertical direction, wherein the release force acts upward on the ball stud in the vehicle vertical direction in the event of a frontal collision. As a result, an opening process is initiated, in which the ball stud is pulled out of the joint housing counter to the joining direction by means of the crash element.An essential aspect of the invention relates to the realization of the support section with which the crash element can be adjusted from its non-use position via the crash path into its operative position. Preferably, the support section can have a radial web projecting from the wheel carrier, which web merges on its side remote from the wheel carrier into a circumferential web. This can extend in the shape of a circular arc with clearance along the rim inner periphery and carry the crash element at its free end.The crash element can be plate-shaped and project radially inward from the support section. The crash element is preferably fork-shaped with two element arms spaced apart from one another, which engage under the ball stud on both sides in the event of a frontal collision and pull it out of the joint housing. The two element arms can preferably be wedge-shaped, namely with ramps inclined relative to one another, which converge at an acute angle in the direction of the joint.In a specific application, the joint can be positioned in a lower link plane on the wheel carrier. In this case, the support section can be linked to the wheel carrier at a connection point which is arranged above a wheel axis by a height offset. The crash element is positioned below the wheel axle by a height offset in order to ensure sufficient plastic or elastic deformability of the support section and to come into a crash connection with the joint.An exemplary embodiment of the invention is described below with reference to the attached figures.The following are shown: FIGS. 1 and 2 each show different perspective views of a wheel suspension with a crash element; and FIGS. 3 and 4 are views illustrating a collision-related pop-up operation.FIGS. 1 and 2 show different views of a wheel suspension for a front axle of a two-track vehicle, which wheel suspension has a wheel carrier 1 which carries a front wheel 3 of the vehicle. The wheel carrier 1 is constructed via a link assembly from a total of two single-cell cores 4, 5 positioned in an upper link plane and two individual links 6, 7 positioned in a lower link plane. Each of the links is articulated at mounting-side bearing points 9 on a vehicle structure, not shown, and is articulated at wheel carrier-side bearing points 11 on the wheel carrier 1. The wheel suspension shown in FIGS. 1 and 2 is also installed on the other side of the vehicle in mirror-image fashion with respect to a longitudinal center plane of the vehicle.In addition, the wheel suspension can have a spring arrangement, not shown, consisting of a shock absorber and a support spring. The front wheel 3 shown in FIGS. 1 and 2 has a tubeless tire 13 embedded in a rim well 15 of a wheel rim 17. The radially outer rim well 15 is connected via an indicated spoke section 19 to a radially inner hub section 21. As can be seen from FIG. 2, the wheel carrier 1 is positioned in a rim interior 25 both in the region of its wheel hub 23 and with its lower wheel carrier-side bearing points 11 of the two lower links 6, 7. This is bounded radially on the outside by a rim inner periphery and in the axial direction by the rim spoke portion 19.According to FIG. 1 or 2, a crash element 27 is formed on the wheel carrier 1, with the aid of which crash element, in the event of a frontal collision, the articulated connection between the front lower link 6 in the vehicle longitudinal direction x and the wheel carrier 1 is released at the bearing point 11 on the wheel carrier side, in order to prevent a crash-induced turning in of the front wheel 3 facing the crash.In order to provide such an operating mechanism in the event of a frontal collision, it is important that the wheel carrier-side bearing point 11 of the front lower link 6 has a ball joint, as is shown roughly schematically in FIG. 3. Accordingly, the ball joint 29 is screwed as a supporting joint in the wheel carrier 1 and supports the front lower link 6. The ball joint 29 transmits axial and / or radial forces during normal driving operation, which are generated by the vehicle weight or during different driving maneuvers of the vehicle. At the same time, the ball joint permits a certain relative movement of the connecting partners, i.e. the front lower link 6 and the wheel carrier 1. The joint housing 31 is screwed with its external thread into the wheel carrier 1. The ball stud 33 has a ball 35 which is rotatably and pivotably mounted in a bearing shell of the joint housing 31 and projects with its stud 37 from a housing opening. This is bounded by an annular closure element 39 which secures the joint ball 35 in the joint housing 31. When the ball joint 29 is assembled, the ball stud 33 formed on the lower front link 6 is inserted into the joint housing 31 in a stud extension direction I (i.e., joining direction) (FIG. 3 ) and secured therein by means of the closure element 39.In the event of a frontal collision, the crash element 27 is displaced with its detachment contour 41 in contact with a guide-arm-side mating contour 43. This can be formed (as shown in FIG. 3 ) directly on the lower link 6 or directly on the ball stud 33. As a result, snapping out takes place, in which the ball stud 33 is pulled out of the joint housing 31 counter to the joining direction with the aid of the crash element 27.As can be further seen from FIGS. 1 and 2, the crash element 27 is fastened to the wheel carrier 1 via a support section 45, namely at a connection point A, which is positioned above a wheel axle indicated in FIG. 1 by a height offset. The support section 45 has a radial web 47 which projects radially outwards in the horizontal direction from the wheel carrier towards the front in the direction of travel FR. On its side remote from the wheel carrier, the radial web 47 merges into a circumferential web 49 which extends in the shape of a circular arc with clearance f along the rim inner periphery 51. At its lower end, the crash element 27 is integrally formed on the circumferential web 49, which crash element protrudes toward the inside of the vehicle in the direction of the ball joint 29 on the wheel carrier side, but does not touch the ball joint 29 in the normal state shown, but rather is spaced apart therefrom by a clearance.It can be seen from FIG. 2 that the crash element 27 is bifurcated in the vehicle longitudinal direction x in the direction of the ball joint 29 into two element arms 53 which have a wedge shape as a detachment contour 41 which tapers towards the vehicle's rear in a wedge shape.The operating mechanism of the crash element 27 is explained below with reference to FIGS. 3 and 4: Consequently, in a frontal collision event with at least a slight lateral overlap, the rim 17 of the crash-facing front wheel 3 is acted upon by impact forces F A( FIG. 4 ), whereby said rim is deformed and comes into pressure contact with the circumferential web 49 of the support section 45 of the crash element 27. The support section 45 is formed with its circumferential web 49 and its radial web 47 sufficiently elastically or plastically deformable on the wheel carrier 1. As a result, the crash element 27 follows the vehicle-rear deforming wheel rim 17 by elastic / plastic deformation of its support section 45; as a result, the crash element 27 is adjusted from a non-use position N (FIG. 3 ) without functioning by a crash path Δx to an operative position W (FIG. 4 ). In the operative position W, the wedge-shaped element arms 53 are keyed between the wheel carrier 1 and the joint 29. In this keyed state, the crash element 27 engages with its two element arms 53 under the mating contour 43 formed on the ball stud 33, whereby a force component acting as a release force F L is exerted towards the vehicle's upper side (i.e. on the ball stud 33, in order to button out the joint connection on the wheel carrier side between the front lower link 6 and the wheel carrier 1. This means that the effective direction of the crash element 27 designed as a spreader wedge is in the exemplary embodiment along the pin axis and opposite to the joint mounting direction.The end of the crash element 27 which is fork-shaped as a result of the wedge shape generates the upward detachment force F L when it penetrates into an intermediate space 50 (FIG. 3 ) between the ball joint 29 and the wheel carrier 1, which detachment force releases the ball joint 29 from a fastening. The force required for this is many times lower than a force required for, for example, tearing off the ball joint 29 in the vehicle transverse direction y. This makes it possible to design the components without the above-mentioned disadvantages.

Claims

Wheel suspension for a front axle of a two-track vehicle, having a wheel carrier (1) which carries a front wheel (3) and is articulated on a vehicle structure via a link assembly, wherein the link assembly has at least one link (6) which is articulated on the wheel carrier (1) via a joint (29) at a bearing point (11) on the wheel carrier side, wherein the wheel carrier (1) is formed with a crash element (27) which, in normal operation, assumes a non-use position (N) in which the crash element (27) is arranged radially within a rim (17) of the front wheel (3) and with a clearance (f) at a distance from an inner periphery (51) of the rim (17), wherein, in a frontal collision event, the rim (17) of the front wheel (3) facing the crash is deformed and comes into pressure contact with the crash element (27) of the wheel carrier (1), characterized in that the crash element (27) has a wedge-shaped detachment contour (41), and in that the crash element (27) is adjustable in the frontal collision event with respect to the wheel carrier (1) by a crash path (Δx), namely up to an active position (W), in which the wedge-shaped detachment contour (41) is keyed between the wheel carrier (1) and the joint (29) in such a way that the crash element (27) exerts a release force (F L) towards the joint (29) in order to release the joint connection between the link (6) and the wheel carrier (1).Wheel suspension according to Claim 1, characterized in that the crash element (27) is formed on the wheel carrier (1) via an elastically or plastically deformable support section (45), and in that the crash element (27) can be adjusted in the event of a frontal collision with respect to the wheel carrier (1) by the crash path (Δx) as far as the operative position (W).Wheel suspension according to Claim 1 or 2, characterized in that the joint (29) has a joint housing (31) which is assigned to a first connection partner and into which a joint part which is assigned to a second connection partner is inserted in a pin extension direction (I) or joining direction, and in that, in the event of a frontal collision, the crash element (27) presses with the release force (F L) onto the joint part, specifically in a direction opposite the pin extension direction (I).Wheel suspension according to Claim 1, 2 or 3, characterized in that the joint (29) is a ball joint, and in that a ball stud (33) is inserted as the joint part in the joint housing (31), and / or in that the joint housing (31) is assigned to the wheel carrier (1), and / or in that the joint part is assigned to the link (6).Wheel suspension according to Claim 4, characterized in that the detachment contour (41) of the crash element (27) interacts with a mating contour (43) of the joint (29), and in that, in the event of a frontal collision, the detachment contour (41) of the crash element (27) comes into contact with the mating contour (43) of the joint (29), specifically with the build-up of the release force (F L), by means of which the joint connection is released.Wheel suspension according to one of the preceding claims, characterized in that the crash element (27) has two element arms (53) which taper towards the vehicle's rear in a wedge-shaped manner.Wheel suspension according to Claim 4, 5 or 6, characterized in that, in the event of a frontal collision, snapping out takes place, in which the ball stud (33) is pulled out of the joint housing (31) counter to the joining direction by means of the crash element (27), and / or in that the stud extension direction (I) is oriented at right angles to a link rod direction.Wheel suspension according to one of the preceding claims, characterized in that the supporting section (45) of the crash element (27) has a radial web (47) which projects from the wheel carrier (1) and which, on its side remote from the wheel carrier, merges into a circumferential web (49) which runs in the shape of a circular arc with clearance (f) along the rim inner periphery (51) and at the free end of which the crash element (27) is formed and projects radially inwards.Wheel suspension according to one of the preceding claims, characterized in that the joint (29) is positioned in a lower link plane on the wheel carrier (1), and / or in that the support section (45) is linked to a connection point (A) on the wheel carrier (1), which connection point is arranged above a wheel axis by a height offset, and / or in that the crash element (27) is arranged below the wheel axis by a height offset.

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