Vibration damper support for a vehicle wheel

Abstract

Strut or vibration damper support by an upper support bearing (1) of a vehicle wheel suspension, which supports a piston rod (11) of a vibration damper (10) via an elastomer element (4) in a strut tower (12) of the vehicle, wherein the support bearing (1) has a passage opening (5) for the piston rod (11) which corresponds to a body passage opening and consists of at least an outer ring (2) connected to the strut tower (12) and an inner ring (3) supporting the piston rod (11) with an elastomeric material inserted between them, wherein the outer ring (2) is attached to the strut tower (12) by means of a device for dissipating kinetic energy which allows movement of the outer ring (2) away from the strut tower (12) when forces exceeding the intended maximum design forces occur.wherein the device for dissipating kinetic energy is integrated into the attachment of the outer ring (2) to the strut tower (12).

Description

[0001] The invention relates to a vibration damper or spring strut support by an upper support bearing of a vehicle wheel suspension, which ultimately supports a piston rod of a vibration damper or spring strut via an elastomer element in a spring strut dome of the vehicle, according to the first claim.

[0002] For design reasons, the hood of a passenger car is positioned as low as possible. In addition to the engine installation space, the spring strut support bearing also plays a decisive role in the height dimension chain. Care must therefore be taken to ensure that the spring strut is positioned as low as possible for a given suspension travel. Since pedestrian protection regulations stipulate that hard parts of the vehicle must be kept a minimum distance from the soft hood, this connection becomes increasingly important. This limits the suspension travel, which is sufficient for normal driving. However, in so-called special events such as driving over an obstacle, a greater suspension travel would be desirable: The wheel is accelerated sharply when driving over a bump and must be fully braked again over the remaining spring travel. This creates very high peak loads that must be absorbed by the body structure.The mount for the strut support bearing must be designed accordingly strong and heavy. The axle components must also be designed to withstand these peak loads, which results in considerable weight.

[0003] Different concepts are known for attaching spring struts of a vehicle wheel suspension to a vehicle body. In multi-track vehicles, the so-called McPherson strut is usually installed on steered wheels. This strut consists of a suspension spring and an associated, parallel-connected damper supported on one side by a wheel guide member and on the other side by a support bearing on the vehicle body. This support bearing can be a rubber-metal bearing, which, as an elastomer element, acts both as a spring and a damper.Typically, the damper's piston rod is attached to the support bearing, while the damper cylinder is supported on the wheel guide member and provided with a receptacle for the suspension spring. A so-called auxiliary spring is also typically provided in this area. This auxiliary spring is also designed as an elastomeric spring element and against which the damper cylinder comes to a stop after a certain spring deflection of the suspension spring. With this travel-dependent, stepped parallel connection of suspension spring and auxiliary spring, the spring characteristics can then be designed relatively easily as desired. In this conventional strut arrangement, which is particularly common on steered wheels, the mechanical load on the support bearing and the strut tower is relatively high, as the latter must also absorb the high forces from the auxiliary spring.Especially when negotiating obstacles, the force transmitted from the outer ring of the support bearing to the strut tower can deform it due to the high force peaks that occur. Designing the strut tower for maximum load makes it heavy and expensive.

[0004] However, the invention does not only apply to strut axles. Rather, it is suitable for all axle types in which at least the damper is connected to the body via a spring or damper dome.

[0005] DE 10 2006 026 822 B4 describes a vibration damper for a vehicle that is sufficiently stiff under normal operating conditions and, at the same time, provides a sufficiently large spring travel during special events, such as crossing a threshold. The auxiliary spring is connected in series with at least one other spring element. By connecting the auxiliary spring in series with the spring element, the overall spring characteristics of the chassis suspension can be easily varied. If the preload force of the spring element corresponds to a force at which the auxiliary spring is already in the progressive, non-linear characteristic range, it is guaranteed that the spring element only provides additional spring travel to absorb the force during a special event outside of normal driving conditions and has no spring properties during normal driving conditions.To enable a compact design of the assembly consisting of the auxiliary spring and the spring element, the spring element can be a disc spring assembly with an extremely low overall height. A conventional stop buffer made of an elastomer material is used as the auxiliary spring.

[0006] Regardless, to avoid damage to the strut tower due to overloading in special events, such as negotiating an obstacle, it must still be designed for maximum load, as the additional spring travel consumes part of the possible spring travel, and the resulting forces cannot be sufficiently dissipated in an energy-dissipating manner, except through deformation of the strut tower. Furthermore, the element described in the patent is arranged in series with the additional spring. This reduces the possible spring travel by this height. However, the goal would be to provide as much spring travel as possible to dissipate the kinetic energy. Therefore, this design for load reduction may even be counterproductive.

[0007] DE 10 2008 010 541 A1 discloses a strut or shock absorber support.

[0008] Therefore, the object of the present invention is to provide a strut or shock absorber support for a vehicle which, on the one hand, has excellent spring and damping properties during normal operation, but on the other hand prevents deformation of the strut dome when stresses exceed the design loads, without the strut dome being designed, for example, in terms of its wall thickness, to withstand these stresses.

[0009] The problem is solved by the features of the first claim. Further embodiments of the invention are described in the dependent claims.

[0010] According to the invention, in a vehicle wheel suspension by means of a spring strut or a shock absorber, an upper support bearing supports a piston rod of the damper via an elastomer element ultimately on a body, in particular in a spring strut dome, of the vehicle.The support bearing has a passage opening for the piston rod, which corresponds to a body passage opening and consists of at least one outer ring connected to the spring strut dome and an inner ring supporting the piston rod, in particular via a rolling bearing, with an elastomeric material, in particular rubber, inserted between them, wherein the outer ring is fastened to the spring strut dome by means of a device for dissipating kinetic energy, which device allows a movement of the outer ring away from the spring strut dome when forces exceeding the intended maximum design forces occur, wherein the device for dissipating kinetic energy is integrated into the fastening of the outer ring to the spring strut dome.

[0011] Such a design of the upper support bearing results in a strut or shock absorber support for a vehicle that exhibits excellent spring and damping properties during normal operation. For very high loads, the strut or shock absorber support according to the invention is advantageously ideally suited because, if excessive force is introduced, the support bearing can dissipate the additional kinetic energy through the kinetic energy dissipation device, which is converted into deformation force. This results in lower body load, preventing permanent body deformation when sudden, large load impacts occur, for example, when driving over an obstacle at high speed.

[0012] As described, the pedestrian protection regulations require a greater distance to the hood above the support bearing. This space can be advantageously used to allow for targeted over-spring travel in the event of an emergency event, incorporating a deformation element. Of course, a combination is also conceivable in which, depending on the height of the load peak, a preloaded spring element according to the state of the art described above is used first, and a component deforms at even higher loads. Ideally, the deformation element should be easy to replace, so that the vehicle owner only suffers relatively minor damage. The spring or deformation elements are designed to only become active in the event of an emergency event. This ensures the required distance to the hood and fulfills the pedestrian protection requirement.Plastic deformation of a component is clearly visible in the position of the vehicle wheel and requires repair in the workshop. Of course, the measures described can also be applied to the rear axle support bearing if sufficient space is available or provided.

[0013] The device for dissipating kinetic energy is integrated into the attachment of the outer ring to the strut tower. This can be advantageously achieved, particularly when the outer ring supports a suspension spring and an elastomeric auxiliary spring connected in parallel with this suspension spring, by connecting the outer ring to the strut tower by means of screws, each with at least one deformation element slid onto each screw.

[0014] During normal driving, the stability of the deformation element prevents the outer ring from shifting. The support bearing acts as an overload protection device when the force at which deformation of a deformation element begins is set so that its value is slightly lower than the force that would lead to component failure.

[0015] Further preferred embodiments of the invention are characterized in that the force that can be transmitted by the deformation elements without deformation is dimensioned such that the deformation elements can transmit at least one load through supporting forces of the suspension spring, the vibration damper and the additional spring to the body and vice versa, which are provided during operation.

[0016] This advantageously ensures that the highest possible load is protected by the overload protection thanks to the inclusion of the auxiliary spring. The stability of the deformation elements can be varied depending on the requirements of different vehicle designs. The desired energy dissipation can also be adjusted by the design of the deformation elements. Additional stops in the compression and / or tension directions can ensure travel limitation. The overload protection can generally be implemented using a preloaded spring element and / or a plastically deformable element.

[0017] Advantageously, the outer ring moves in the compression direction when the deformation elements are deformed. The force that can be transmitted by the deformation elements without deformation should be selected such that movement of the outer ring occurs when forces are transmitted through the support bearing that would cause permanent deformation of the body without outer ring movement. If overloading occurs, i.e. forces exceeding the intended maximum design forces, these measures prevent permanent deformation of the strut dome even without large sheet metal reinforcements, thus avoiding costly repair measures and advantageously enabling the body structure to be designed for lower maximum loads. The maximum force that can be introduced into the body structure without deformation can be scaled accordingly. Various mountable deformation elements enable scalability in assembly.

[0018] In a further preferred embodiment of the invention, a displacement of the outer ring or a deformation of at least one deformation element can be registered and communicated to the driver via a display device. Such advantageous indication of an overload event, which can be provided, for example, visually using a color scale or electrically using a shear wire or end contact on the outer rings or deformation elements, facilitates damage detection during service. Furthermore, the driver is also informed of damage by the vehicle's tilt or wheel position, allowing, for example, the axle components to be checked for damage.

[0019] A preferred embodiment of the present invention is illustrated in the accompanying drawings. Fig. 1: a partial section through a spring strut support of a wheel suspension with a support bearing according to the invention and Fig. 2: a partial view of the strut support from Fig. 1 from the top.

[0020] Not shown in the figures is a wheel guide member of a wheel of a multi-track motor vehicle, since the design of a spring strut or shock absorber in this area is common in the known art and is not limited to a specific axle type. The present invention relates to the opposite area of ​​the spring strut or shock absorber, namely its support on a spring or shock absorber dome of the motor vehicle. Components of the spring strut include a suspension spring (not shown), with which a damper 10 (only partially shown) with a piston rod 11 is connected in parallel. A motor vehicle body is supported on the wheel guide member via this spring strut. The support area on the body is shaped as a spring strut dome 12.An upper support bearing 1, consisting of an outer ring 2, an inner ring 3 and an elastomer element 4 located therebetween, has a passage opening 5 for the piston rod 11 of the damper 10 and connects the strut dome 12 to the piston rod 11 by mounting the latter in the inner ring 3 of the support bearing 1, secured by a central nut 13 screwed onto the free end of the piston rod 11.

[0021] The corresponding counterbearing for this is formed on the outer ring 2, whose outer region 6 facing the interior of the strut dome forms a suspension spring support. A rubber-elastic, so-called auxiliary spring 14 is arranged on the piston rod 11 of the damper 10. Upon appropriate compression of the suspension spring and thus upon corresponding displacement of the piston rod 11 into the damper cylinder 15 of the damper 10, the damper cylinder 15 can come to a stop with its side facing the body (or the support bearing 1). This auxiliary spring 14 is held by the outer ring 2 and the piston rod 11.

[0022] The longitudinal axis 16 of the suspension strut, which is essentially determined by the axis of the damper 10 or its piston rod 11, essentially coincides with the axis of the support bearing 1. The piston rod 11 penetrates the inner ring 3 of the support bearing 1 in the aforementioned through-opening 5, which corresponds to a body through-opening in the strut tower 12, into which the outer ring 2 is installed. The support bearing 1 supports the damper 10 with the surrounding suspension spring via the upper end of the piston rod 11, opposite the wheel guide member mentioned above, on the body in the strut tower 12 and is connected to the latter by means of screw bolts 7, deformation elements 8 attached thereto, and screwed-on nuts 9.

[0023] The stability of the deformation elements 8 is dimensioned such that they can transmit at least one load from the supporting forces of the shock absorber, the suspension spring, and the auxiliary spring to the body, and vice versa, as required during operation. This prevents operational forces from causing relative movement between the outer ring 2 and the strut tower 12. Only when compressive forces greater than the intended operational forces occur do the deformation elements 8 deform and the outer ring 2 shift in the compression direction, dissipating kinetic energy through deformation in the deformation elements 8. The outer ring 2 is displaced into a space between the strut tower 12 and the bonnet, which must be maintained due to pedestrian protection regulations. This energy dissipation prevents permanent deformation of the body.

[0024] Additional deformation elements not shown between outer ring 2 and strut dome 12 can also be designed as predetermined breaking points and then prevent relative movement between outer ring 2 and strut dome 12 in the tensile direction, i.e., the rebound direction, under normal operating forces. Only when tensile forces greater than the intended operating forces occur do these additional deformation elements deform, and outer ring 2 shifts downward, also dissipating kinetic energy through deformation of the additional deformation elements. This energy dissipation then prevents permanent deformation of the body even in the event of excessive loading in the tensile direction.

[0025] In general, the invention is to provide a support bearing 1 with cost-effective, process-reliable overload protection for components and systems that are exposed to vertical loads, such as bodywork, particularly strut towers, and chassis components. The additional support bearing components that provide overload protection require no additional installation space, do not collide with control arms, wheels, and output shafts in the event of damage, and enable clear indication and cost-effective component replacement in the event of damage. Furthermore, they are well protected from external influences due to their location in the upper spring support area.

[0026] A displacement of the outer ring 2 or a deformation of at least one deformation element 8 can also be detected, for example, by a suitable sensor according to the prior art and communicated to a driver via a display device, for example in a display instrument. Alternatively, the use of an existing error memory system is also possible.

[0027] This arrangement allows for significantly reduced load peaks during special events. Accordingly, the body and axle components can be designed for smaller loads, saving weight and material costs. The visible deformation of deformation element 8 makes it clear to the workshop that improper loads have been applied.

[0028] Typically, the damper bearing is inserted into the body mount from below during axle assembly and screwed into place. To allow for over-travel, the support bearing 1 must be able to deflect upwards, which is not possible with the current arrangement. Therefore, the support bearing 1 must be mounted from above. Fig. 2 shows a possibility with fastening claws 17, how the damper 10 can be pushed through the strut dome 12 during assembly from below using cutouts 18 and then screwed from above.

Claims

[1] Suspension strut or vibration damper support by an upper support bearing (1) of a vehicle wheel suspension, which supports a piston rod (11) of a vibration damper (10) via an elastomer element (4) in a suspension strut dome (12) of the vehicle, wherein the support bearing (1) has a passage opening (5) for the piston rod (11), which corresponds to a body through-opening and consists of at least one outer ring (2) connected to the suspension strut dome (12) and an inner ring (3) supporting the piston rod (11) with elastomer material inserted therebetween, wherein the outer ring (2) is fastened to the suspension strut dome (12) by means of a device for dissipating kinetic energy, which device allows a movement of the outer ring (2) away from the suspension strut dome (12) when forces exceeding the intended maximum design forces occur,wherein the device for dissipating kinetic energy is integrated into the fastening of the outer ring (2) to the spring strut dome (12)., [2] Suspension strut or vibration damper support according to claim 1, characterized by that the outer ring (2) supports a suspension spring and an elastomeric auxiliary spring (14) connected in parallel to this suspension spring. [3] Suspension strut or vibration damper support according to claim 1 or 2, characterized by that the outer ring (2) is connected to the spring strut dome (12) by means of screws (7), with at least one deformation element (8) pushed onto each screw (7). [4] Suspension strut or vibration damper support according to claim 3, characterized bythat the force that can be transmitted by the deformation elements (8) without deformation is dimensioned such that the deformation elements (8) can transmit at least one load due to the supporting forces of the suspension spring, the vibration damper (10) and the additional spring (14) on the body and vice versa, which are provided for during operation. [5] Suspension strut or vibration damper support according to one of claims 3 to 4, characterized by that when the deformation elements (8) are deformed, the outer ring (2) moves in the compression direction. [6] Suspension strut or vibration damper support according to one of claims 3 to 5, characterized by that the force that can be transmitted by the deformation elements (8) without deformation is selected such that a movement of the outer ring (2) takes place when forces are transmitted by the support bearing (1) which, without outer ring movement, would cause a permanent deformation of the body. [7] Suspension strut or vibration damper support according to one of claims 1 to 6, characterized by that a displacement of the outer ring (2) or a deformation of at least one deformation element (8) is registered and communicated to a driver by a display device.

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