DE102009020108A1 - Wheel suspension for motor vehicle, has steering wheel linked at motor vehicle structure, where steering wheel is connected with wheel carrier in articulated manner and carries carrier spring element - Google Patents

Abstract

The wheel suspension has a steering wheel (18) linked at a motor vehicle structure (22), where steering wheel is connected with a wheel carrier (12) in articulated manner and carries a carrier spring element (26,28). The carrier spring element is diametrically supported by intermediate switched rotation plate (30,32) at the steering wheel and at the structure. The carrier spring element is formed by two springs arranged to the axis of rotation (M) of the rotation plates. An independent claim is also included for a method for adjustment of a spring temper of a carrier spring element in a wheel suspension.

Description

The The invention relates to a suspension for motor vehicles according to the preamble of claim 1 and also a method for adjusting a spring rate of a suspension spring element in a wheel suspension according to claim 16.

Such a suspension describes, for example, the DE 25 38 103 A1 in which the compression of the body of the motor vehicle or to compensate for additional loads, the helical compression springs are adjusted between each link of the suspension and the construction of the motor vehicle. For this purpose, the springs are supported eccentrically on turntables, wherein the force of action line (spring center axis) is displaced by rotation of the turntable more or less away from the pivot axis of the handlebar. Thus, the spring hardness or preload force is changed, but not the spring rate. The off-center support also leads to a tension or torsional moments on the handlebar bearings.

To avoid such torsional features, it is by the DE 10 2006 049 726 A1 also known, the adjusting mechanism of the spring plate form such that the force lines of action of the springs linearly and substantially along the Lenkerlängsmittelachse emigrate.

task The invention is a suspension of the generic To propose kind, which has an advantageous influence on the spring properties the suspension allows.

These Object is according to the invention with the characterizing Characteristics of claim 1 solved. Advantageous and expedient developments of the invention include the dependent claims.

According to the invention, it is proposed that the suspension spring element is formed by two springs, in particular helical compression springs, arranged diametrically to the axis of rotation of the spring plate, whose force action lines can have at least substantially equal distances from the axis of rotation of the turntable. The two springs can have different spring rates D ₁ and D ₂ . These spring rates form with a corresponding adjustment of the two springs by changing the gear ratios i in a simple manner a variable Gesamtfederkonstante. Furthermore, it can be achieved by a suitable design of the two springs that their total spring constant can be adjusted to influence a defined driving behavior of the motor vehicle in more comfortable or more sporty.

The spring lengths of the two springs can be determined so that in the structural position of the suspension, the acting spring forces are the same. By rotation of the turntable, the spring ratios i ₁ and i _{2 are} changed. The force acting on the wheel remains the same, so that no height adjustment of the vehicle in the design point, that is in the design situation, takes place, but only changes the effective spring rate. In the design situation results in a predetermined predetermined vehicle weight at a predetermined vehicle weight.

in the above embodiment, the two springs be biased in the construction situation with the same force. are however, the biases of the two springs in the design position different, so can by rotation of the turntable simultaneously achieved an adjustment of level and effective spring rate become.

The Ratio of level adjustment and spring hardness adjustment can by selecting the initial parameters (spring rates and preload) be set. By a stronger bias the Soft spring can simultaneously lower the vehicle and the effective Spring hardness can be increased.

exemplary is assumed in the following from a starting position (construction), in which the soft spring lies in the transverse direction outside and is strongly biased while the hard spring is inside, that is closer to the vehicle center, lies and less biased is: During a rotary movement of the turntable is therefore the soft Spring inwards and the hard spring adjusted outwards. In this way, the bias increases inside so that the vehicle is lowered overall. The bigger one Spring rate shifts to the outside, causing the effective spring hardness increases.

Prefers can the force lines of action of the two springs in at least a design arrangement, the Lenkerlängsmittelachse pierced. This means that in a basic vote the two springs in Vehicle transverse direction are aligned so that a spring closer and the other spring is further away from the handlebar pivot axis.

Furthermore, the lengths of the two springs can be designed such that in the construction position of the suspension (under design load) the acting spring forces F ₁ and F _{2 are the} same. As a result, with an adjustment of the two springs, the spring forces remain approximately the same, while changing the overall spring constant.

Especially can according to mathematical equation and possibly by empirical Try the two springs to be tuned so that at a defined Rotation of the turntable the spring forces under construction load stay the same and only the effective spring rate changes. In particular, the turntable can over be a rotation angle α of about 180 ° adjustable.

The Turntables can also in a conventional manner via Bearings mounted on the handlebar and the body and by means of at least one electric motor with a self-locking gear be adjustable. Preference can be given to the electric motor and the transmission to be arranged on the body-side turntable.

In a further embodiment of the invention, the suspension spring element in particular linear along a longitudinal axis of the handlebar of the Handlebars are adjusted to the spring stiffness, but not the vehicle height, change.

in the Area of the adjustment of the suspension spring element, the Handlebar support and the spring support to each other be aligned in parallel. Changes in an adjustment of the suspension spring element Therefore, the spring ratio and thus the spring force. Along with an associated change in length of the suspension spring element this leads to an adjustment of the Vehicle level.

exemplary can the rotational movement of the turntable via an adjustment In addition, a linear adjustment along the handlebar longitudinal axis superimposed be. The combination of the rotary adjustment and a linear adjustment allows advantageous, more degrees of freedom in the constructive design of the vehicle suspension, in addition to the variable Design of spring rates also a height adjustment of the Body is accomplished.

The adjusting mechanism can be formed in a particularly simple manner in terms of production engineering and construction, in each case by a stationary toothed rack and an external toothing on the turntable, wherein the turntable can be linearly displaced via a sliding guide with a displaceable sliding block serving as a rotary bearing for the turntable. However, the adjusting mechanism can alternatively also according to the above-mentioned DE 10 2006 049 726 A1 be executed.

Of Further may be in the structural position of the suspension in the region of the adjustment of the suspension spring element, the handlebar support not parallel to the body-side spring support, but be convergent or divergent. This represents another, structurally relatively simple measure, depending on the spring rate and the vehicle height purposefully coordinated by constructive conditions. By a converging or divergent orientation of the handlebar support and the body-side spring support can be a height change amplified, attenuated or reversed.

After all can without any additional effort and in further specification of the Spring characteristics over the occurring static and Dynamic driving loads the characteristic of at least one of the two helical compression springs be progressive or degressive.

Two Embodiments of the invention are in the following further details explained. The schematic Drawing shows in:

1 a rear view of a partially shown, rear wheel suspension for motor vehicles, with a lower wheel guide arm and two adjustable via turntable helical compression springs, which are supported on the structure of the motor vehicle;

2 a sketchy plan view of the lower arm according to 1 showing the spring assembly relative to the pivot axis of the handlebar;

3 a diagram of changing over the angle of rotation of the turntable spring hardness D _R to D _Rmax ,

4 a plan view of an alternative arrangement of the two helical compression springs on the handlebar of the suspension with an additional adjustment, which overlaps the rotational movement of the turntable a linear adjustment; and

5 a rear view of a suspension after 4 , in which, in the region of the linear adjustment of the helical compression springs, the lower link of the wheel suspension converges outwardly to the support surface of the helical compression springs on the superstructure.

In the 1 is roughly schematically a rear suspension 10 illustrated for motor vehicles, with one on a wheel carrier 12 rotatably mounted rear wheel 14 , At the wheel carrier 12 are an upper, only partially illustrated wishbone 16 and a lower, in construction position approximately horizontally oriented handlebars 18 via appropriate joints 20 hinged. Opposite are the handlebars 16 . 18 at the construction 22 the body of the vehicle pivotally mounted. It's just the pivot bearings 24 of the lower handlebar 18 seen.

At the lower handlebar 18 are two helical compression springs 26 . 28 as suspension springs with the interposition of a turntable 30 supported, at its upper end also with the interposition of a turntable 32 in the area of a longitudinal member 34 at the construction 22 issue.

The turntables 30 . 32 are about ring-shaped bearings 36 relative to the handlebar 18 and to the construction 22 rotatably mounted. In addition, the upper turntable 32 over a centric axis 38 with a self-locking gear 40 and an electric motor 42 connected by love.

The self-locking gearbox 40 can z. B. on the axis 38 be located worm wheel, which via a drive screw (not shown) of the electric motor 42 is driven and the turntable 32 adjusted over a defined rotation angle α. About the springs 26 . 28 becomes the lower turntable 30 mitverdreht accordingly. The electric motor 42 can be controlled via an electronic control unit (not shown) in accordance with driving dynamics parameters to adjust its spring characteristics (comfort or sporty).

The arrangement and design of the two springs 26 . 28 is related to 2 and by the lower, on the handlebar 18 arranged turntable 30 explained in more detail.

The total length l _{ges of} the handlebar 18 is defined by the hinge or pivot axes 44 . 46 of the handlebar 18 , The pivot point M of the turntable 30 has a distance I _m to the pivot axis 46 on and also lies in the longitudinal center axis 48 , in turn, by the not shown joint centers of the handlebar 18 certainly.

The two smaller in diameter than the turntable 30 executed, circular symmetrical springs 26 . 28 lie with their force line of action 50 diametrically at a distance I _e to the center M opposite. The on the turntable 30 exerted spring forces F largely compensate accordingly and practice neither a tilting moment on the turntable 30 nor a torsional moment about the longitudinal central axis 48 of the handlebar 18 provided the forces of the two springs 26 . 28 are about the same.

The feathers 26 . 28 are in the said construction position of the suspension 10 and at a defined load of the motor vehicle designed so that they have different spring rates D ₁ , D ₂ .

In addition, in this design state, the lengths of the two springs 26 . 28 determined so that the acting spring forces F ₁ , F _{2 are the} same.

By turning the turntable 30 . 32 by a defined angle α, preferably between 0 ° and 180 °, the spring ratios i ₁ and i _{2 are} changed because their force lines of action 50 to the pivot axis 46 of the handlebar 18 move.

The at the rear wheel 14 acting force remains the same, so that no height adjustment of the motor vehicle takes place in its construction position. The at the rear wheel 14 effective effective spring hardness D _R , however, changes according to the following equation: D R = D 1 i 2 1 + D 2 i 2 2

It applies to the force F on the rear wheel 14 :

As a result, FR remains constant for all angles of rotation α, if, as stated, F ₁ = F ₂ (applies exactly only in the construction position with the handlebars aligned horizontally 18 ).

For the effective spring rate D _R applies accordingly:

The diagram according to 3 shows the qualitative course for D _R (effective spring rate) on the rotation angle α of the turntable 30 or the springs 26 . 28 receiving turntable 30 . 32 ,

By turning the turntable 30 . 32 via the self-locking gear 40 and the electric motor 42 and a corresponding shift of the force action lines 50 the springs 26 . 28 So can the effective spring D _R at the rear wheel 14 be adjusted continuously.

The 4 the drawing shows in a plan view of the handlebar 18 the suspension 10 an alternative embodiment, in which at the turntables 30 . 32 (it's just the lower turntable 30 visible) an additional adjustment 52 is arranged, the case of a rotation of the turntable 30 . 32 a linear displacement of the two helical compression springs 26 . 28 by a defined displacement s causes.

The adjusting mechanism 52 has a stationary rack 54 on the handlebar 18 is attached. The rack 54 is in engagement with an external toothing 56 at one with the turntable 30 firmly connected gear may be formed or as shown in simplified form on the turntable 30 is formed. The adjustment s at a defined rotation of the turntable 30 determined by the diameter of the external toothing 56 ,

The turntable 30 (or one with the turntable 30 connected gear) is in a sliding block 58 over a bearing axis 60 rotatably mounted. The sliding block 58 in turn is in a slot-shaped slotted guide 62 along the longitudinal axis 48 of the handlebar 18 slidably guided.

It should be noted that the turntable 32 on the structure of the motor vehicle is arranged analogously linearly adjustable and on the central axis 38 , the self-locking gearbox 40 and the electric motor 42 (see. 1 ) is rotatable.

Will the turntables 30 . 32 as described above z. B. by means of the electric motor 42 twisted, they are additionally on the stationary racks 54 as supporting organs and over their external teeth 56 along the slide tours 62 linearly displaced over the displacement s, wherein the distance between the central axis M, with the bearing axis 60 or the centric axis 38 the turntable 30 . 32 coincides, to the pivot axis 46 of the handlebar 18 changed accordingly.

In addition to the above-described change in the spring rates, this also causes an increase or decrease in the spring forces F ₁ , F ₂ , because the additional, linear displacement of the two springs 26 . 28 whose transmission ratio i ₁ , i ₂ additionally changed accordingly. The vehicle level can be raised or lowered accordingly.

The 5 shows a further variant of the influence of the spring forces F ₁ , F _{2 of} the two springs 26 . 28 in which the areas 18a . 22a the spring supports on the handlebar 18 and / or on the construction 22 of the motor vehicle does not look like 1 can be seen substantially horizontally and parallel to each other, but converging or diverging (see lines 64 . 66 ) are executed. Alternatively to the in the 4 and 5 shown embodiments, that of the two springs 26 . 28 be formed spring element also be designed as a single spring.

In the embodiment 5 is in the design position of the suspension 10 the area 18a of the handlebar 18 inside, the handlebar bearing 24 too divergent with respect to the approximately horizontal area 22a of the construction 22 designed. As a result, with a linear displacement of the two springs 26 . 28 With their turntables 30 . 32 externally increases the spring preload and the vehicle level is raised.

An inverse effect is achieved when the areas 18a . 22a executed converging, whereby the vehicle level is lowered in an adjustment to the outside.

An additional possibility is the use of one or more springs with nonlinear spring characteristic (degressive or progressive spring). For example, in an arrangement in which the areas 18a . 22a running in the vehicle transverse direction outwardly converging, a progressive spring (spring rate is greater with the force used), a height adjustment of the vehicle can be done without changing the effective spring rate. So changes in an adjustment of the spring to the outside of the spring ratio. As a result, the spring force decreases, so that the suspension spring element is longer and the vehicle lifts.

Instead of the inclined area 18a on the handlebar 18 may also or alternatively the range 22a be designed appropriately inclined to the structure, depending on design and structural constraints or requirements.

By designing the inclined areas 18a . 22a more or less convergent or divergent additional constructive influence on the suspension properties can be exercised, and to an increasing extent the spring forces F ₁ , F ₂ and the total spring hardness can be varied depending on required driving characteristics under different load conditions of the motor vehicle.

At least one of the two helical compression springs 26 . 28 can also be designed with a non-linear characteristic (progressive or degressive).

For example, in a converging interpretation of the spring support surfaces 18a . 22a between the handlebars 18 and the construction 22 progressively designed helical compression springs 26 . 28 used with the spring travel increasing spring rate, a height adjustment of the vehicle can be done without changing the effective spring rate.

By a combination of the above-mentioned possibilities (two in the interpretation different helical compression springs 26 . 28 , additional linear displacement s, inclined support surfaces 18a . 22a , Nonlinear characteristics) is an optimization of the suspension and handling characteristics of the motor vehicle, in particular with regard to space, spring travel, minimization of the loading influence, etc. created, in the context of the invention, some or all of the possibilities described are exhaustible.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 2538103 A1 [0002]
• - DE 102006049726 A1 [0003, 0018]

Claims (16)

Wheel suspension for a motor vehicle, with a vehicle body ( 22 ) articulated handlebars ( 18 ), which articulates with a wheel carrier ( 12 ) is connected and a suspension spring element ( 26 . 28 ), the construction ( 22 ), the force line of action ( 50 ) of the suspension spring element ( 26 . 28 ) is adjustable in the vehicle transverse direction, characterized in that the suspension spring element ( 26 . 28 ) by means of interposed turntable ( 30 . 32 ) on the handlebar ( 18 ) and on the construction ( 22 ) is rotatably supported, and by two diametrically to the rotation axis (M) of the turntable ( 30 . 32 ) arranged springs, in particular helical compression springs, is formed. Wheel suspension according to claim 1, characterized in that the force action lines ( 50 ) of the springs ( 26 . 28 ) at least substantially equal distances (I _e ) to the axis of rotation (M) of the turntable ( 30 . 32 ) exhibit. Wheel suspension according to claim 1 or 2, characterized in that the force action lines ( 50 ) of the two springs ( 26 . 28 ) in at least one design position, the handlebar longitudinal center axis ( 48 ). Wheel suspension according to claim 1, 2 or 3, characterized in that the two springs ( 26 . 28 ) have different spring rates (D ₁ ) and (D ₂ ). Wheel suspension according to one of the preceding claims, characterized in that the lengths of the two springs ( 26 . 28 ) are designed in an unloaded state such that in a constructional position of the suspension ( 10 ) the acting spring forces (F ₁ , F ₂ ) are the same. Wheel suspension according to one of claims 1 to 5, characterized in that the lengths of the two springs ( 26 . 28 ) are designed in the unloaded state such that in the construction position of the suspension ( 10 ) the acting spring forces (F ₁ and F ₂ ) are different, that is the springs ( 26 . 28 ) are subjected to different bias voltage. Wheel suspension according to one of the preceding claims, characterized in that the two springs ( 26 . 28 ) are tuned so that upon rotation of the turntable ( 30 . 32 ) The spring forces (F ₁ , F ₂ ) remain the same and only the effective spring hardness (D _R ) changes. Wheel suspension according to one of the preceding claims, characterized in that the turntables ( 30 . 32 ) are adjustable over a rotation angle (α) of about 180 °. Wheel suspension according to one of the preceding claims, characterized in that the turntables ( 30 . 32 ) via rolling bearings ( 36 ) on the handlebar ( 18 ) and on the construction ( 22 ) are stored, and in particular by means of at least one electric motor ( 42 ) with a self-locking gear ( 40 ) are adjustable. Wheel suspension according to claim 9, characterized in that the electric motor ( 42 ) and the transmission ( 40 ) with the body-side turntable ( 32 ) interact. Wheel suspension for a motor vehicle, in particular according to one of the preceding claims, with a motor vehicle body ( 22 ) articulated handlebars ( 18 ), which articulates with a wheel carrier ( 12 ), and a suspension spring element ( 26 . 28 ), the construction ( 22 ), the force line of action ( 50 ) of the suspension spring element ( 26 . 28 ) is adjustable in the vehicle transverse direction, characterized in that the suspension spring element ( 26 . 28 ) along a longitudinal axis of the handlebar ( 48 ) is adjustable. Wheel suspension according to one of the preceding claims, characterized in that in a constructional position of the wheel suspension ( 10 ) in the region of the adjustment path (s) of the suspension spring element ( 26 . 28 ) in the vehicle transverse direction, the handlebar support ( 18a ) and the body-side spring support ( 22a ) are convergent or divergent to each other. Wheel suspension according to one of the preceding claims, characterized in that the characteristic curve of at least the suspension spring element ( 26 . 28 ) or the two springs of the suspension spring element is designed progressive or degressive. Wheel suspension according to one of the preceding claims, characterized in that the rotational movement of the turntable ( 30 . 32 ) via an adjusting mechanism ( 52 ) a linear adjustment along the handlebars longitudinal axis ( 48 ) is superimposed. Wheel suspension according to claim 14, characterized in that the adjusting gear ( 52 ) by a stationary rack ( 54 ) and an outer toothing ( 56 ) on the turntable ( 30 . 32 ) is formed, wherein the turntable ( 30 . 32 ) via a link guide ( 62 ) with a sliding, as a pivot bearing for the turntable ( 30 . 32 ) serving sliding block ( 58 ) is linearly displaceable. Method for adjusting a spring stiffness of a suspension spring element ( 26 . 28 ) in a wheel suspension according to one of the preceding claims.