The invention relates to a wheel suspension for a vehicle axle of a two-track vehicle according to the preamble of claim 1.
Such a wheel suspension has a wheel carrier carrying a vehicle wheel, which is articulated to a subframe or axle carrier of the vehicle via a multi-link assembly. The subframe is in turn connected to the vehicle body (e.g., the body side members) via subframe bearings.
A longitudinal force acts on the vehicle wheel when the vehicle drives over an edge or when it is accelerating or decelerating. With regard to longitudinal suspension comfort, prior-art subframe bearings, via which the subframe is connected to the body, are designed with an increased elastic longitudinal compliance in the vehicle's longitudinal direction to absorb the longitudinal force acting on the vehicle wheel. In the case of a trapezoidal link vehicle axle, in the prior art, this also results in the trapezoidal link being twisted and/or in the trapezoidal link being displaced longitudinally by a longitudinal path in the vehicle's longitudinal direction. In the above case, the trapezoidal link longitudinal path is limited in particular by stops on the trapezoidal link bearings located inside the vehicle.
In the event that the above vehicle axle, designed with regard to longitudinal suspension comfort, is operated electrically, the following situation arises: an electric machine can either be mounted on the subframe or close to the wheel on the trapezoidal link of the wheel suspension and be drivingly connected to the vehicle wheel via a drive shaft. In this case, when a longitudinal force acts on the vehicle wheel, the longitudinal displacement of the subframe and/or the trapezoidal link results in undesired electrical machine vibrations.
DE 10 2011 055 704 A1 discloses a generic multi-link rear axle for a motor vehicle having a trapezoidal link. DE 694 12 909 T2 also discloses a wheel suspension having a trapezoidal link.
The object of the invention is to provide a wheel suspension with particularly high longitudinal comfort. In addition, the wheel suspension of an electrically operated vehicle axle is to avoid undesired vibrations due to the electric machine mass.
The object is achieved by the features of claim 1. Preferred further improvements of the invention are disclosed in the dependent claims.
The invention is based on a wheel suspension, the wheel carrier of which is articulated to the vehicle body via a multi-link assembly. The multi-link assembly has a trapezoidal link designed as a four-point link, which has two connection points on the body side and two connection points on the wheel carrier side. According to the characterizing part, the connection points on the wheel carrier side are designed with greater elastic longitudinal compliance, that is, softer, than the connection points on the body side. Therefore, when a longitudinal force acts on the vehicle wheel, the wheel carrier is displaced by a longitudinal path in the vehicle's longitudinal direction with respect to the trapezoidal link (which is largely not displaced longitudinally). Due to the now greater longitudinal compliance on the wheel carrier side, the subframe bearings can be made more rigid. In particular, when combining the vehicle axle with an electric machine, this offers the following advantage: the electric machine can be disposed on the subframe or, when supported close to the wheel, on the trapezoidal link. Therefore, according to the invention, when a longitudinal force acts on the vehicle wheel, there is no or only minimal longitudinal movement of the subframe or the trapezoidal link due to the now more rigid subframe bearings and/or trapezoidal link bearings on the body side. Correspondingly, the electric machine mounted on the subframe or the trapezoidal link is also not subject to any longitudinal movements, thereby eliminating or significantly reducing undesired vibrations during travel.
In one technical implementation, the multi-link assembly is articulated to a subframe via connection points on the body side. The subframe is in turn connected to the vehicle body (e.g., body side members) via subframe bearings. The subframe or the trapezoidal link can carry an electric machine drivingly connected to the vehicle wheel via a drive shaft. According to the invention, in the vehicle's longitudinal direction, compared to the trapezoidal link connection points on the wheel carrier side, the subframe bearings and the connection points of the multi-link assembly on the body side are designed such that most of the longitudinal compliance results from the connection on the wheel carrier side.
In addition to the trapezoidal link, the multi-link assembly can have exactly three further suspension links. In particular, these can be provided in the form of two-point links, each with a connection point on the body side and a connection point on the wheel carrier side. Preferably, the three further suspension links can be implemented as control arms extending in alignment with the vehicle's transverse direction. All of the connection points of the multi-link assembly on the body side and on the wheel carrier side can be implemented as swivel bearings having a swivel axis aligned with the vehicle's longitudinal direction.
When a longitudinal force acts on the vehicle wheel, the three further suspension links can determine the wheel carrier movement. This mainly includes longitudinal displacement of the wheel carrier, superimposed by a slight toe-in or toe-out rotation of the wheel carrier.
In a specific embodiment variant, the trapezoidal link can be disposed in a lower link plane together with a suspension link below the vehicle. In the lower link plane, the lower suspension link can be positioned underneath the trapezoidal link with a free vertical offset. Thus, the connection point of the lower suspension link on the wheel carrier side can be disposed underneath the trapezoidal link connection points on the wheel carrier side with a vertical offset.
An upper suspension link at the front of the vehicle and an upper suspension link at the rear of the vehicle can be disposed in an upper link plane. The connection point of the front upper suspension link on the wheel carrier side and the trapezoidal link connection points at the front of the vehicle can be disposed in front of a vehicle wheel rotation axis in the direction of travel. In contrast, both the connection points of the lower suspension link on the wheel carrier side and the upper suspension link at the rear of the vehicle and the trapezoidal link connection points at the rear of the vehicle can be disposed behind the vehicle wheel rotation axis.
In a further improvement of the invention, the connection point of the front upper suspension link on the wheel carrier side can be disposed in front of the front trapezoidal link connection point on the wheel carrier side with a longitudinal offset. Alternatively and/or additionally, the connection point of the front upper suspension link on the wheel carrier side can be disposed above the front trapezoidal link connection point on the wheel carrier side with an upward offset.
The connection point of the rear upper suspension link on the wheel carrier side can be disposed above the rear trapezoidal link connection point on the wheel carrier side with an upward offset. Alternatively and/or additionally, the connection point of the rear upper suspension link on the wheel carrier side can be disposed in front of the rear trapezoidal link connection point on the wheel carrier side with a longitudinal offset.
In a first embodiment variant, the trapezoidal link connection points on the wheel carrier side can be implemented as rubber-metal sleeve bearings. To limit the longitudinal path of the wheel carrier (when a longitudinal force acts on the vehicle wheel), axially acting longitudinal stops can be provided in the respective rubber-metal sleeve bearing. Each of the rubber-metal sleeve bearings can have an inner bearing sleeve passed through by a bearing pin defining the swivel axis, an outer bearing sleeve connected to the trapezoidal bearing, and an elastomer body. The elastomer body can connect the inner bearing sleeve and the outer bearing sleeve to each other. The bearing pin can be supported in opposite trapezoidal link console wings.
In a second embodiment variant, the trapezoidal link connection points on the wheel carrier may not be implemented as rubber-metal sleeve bearings, but rather each be provided with coupling rods via which the trapezoidal link is suspended from the wheel carrier. Each of the coupling rods can be articulated at a lower articulation point on the trapezoidal link and can be articulated at an upper articulation point on the wheel carrier. The articulation points can be implemented as swivel bearings with swivel axes aligned with the vehicle's transverse direction. To limit the longitudinal path of the wheel carrier, a spring-damper element can be interposed between the trapezoidal link and the wheel carrier.
In the following, an exemplary embodiment of the invention is described with reference to the accompanying figures.
In the drawings:
As can also be seen from the figures, multi-link assembly 3 has a trapezoidal link L1 in the form of a four-point link. The latter is disposed in a lower link plane, together with a lower suspension link L3 disposed beneath trapezoidal link L1 with an upward offset z3 (
In the following, the link assembly is described in detail: accordingly, connection point 29 of front upper suspension link L2 on the wheel carrier side and the two trapezoidal link connection points 21, 25 at the front of the vehicle are disposed in front of a vehicle wheel rotation axis D (
In
Connection point 33 of rear upper suspension link L4 on the wheel carrier side is positioned above rear trapezoidal link connection point 27 on the wheel carrier side with an upward offset z4. Further, connection point 33 on the wheel carrier side is positioned in front of rear trapezoidal link connection point 27 on the wheel carrier side with a longitudinal offset.
Front trapezoidal link connection points 21, 25 on the body side and on the wheel carrier side are positioned next to each other in approximate alignment with the vehicle's transverse direction y. In the same manner, rear trapezoidal link connection points 23, 27 on the body side and on the wheel carrier side are positioned in transverse alignment with each other.
In the first exemplary embodiment of
The essence of the invention is the fact that trapezoidal link connection points 25, 27 on the wheel carrier side, implemented as rubber-metal sleeve bearings, are designed with greater elastic longitudinal compliance, that is, softer, than trapezoidal link connection points 21, 23 on the body side and subframe bearing 15. Hence, when a longitudinal force acts on vehicle wheel 2 during travel, wheel carrier 1 is displaced by a longitudinal path Δx (
The longitudinal displacement across longitudinal path Δx of wheel carrier 1 is determined by the three suspension links L2, L3 and L4. As such, the longitudinal displacement of wheel carrier 1 can be superimposed by a slight toe-in or toe-out rotation.
In
In
Number | Date | Country | Kind |
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10 2019 203 836.0 | Mar 2019 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/051498 | 1/22/2020 | WO | 00 |