DE102015214461B4 - Switchable bearing bush for a motor vehicle - Google Patents

Abstract

Bushing (1) for a motor vehicle, comprising an inner ring (3) arranged at least indirectly on a bolt (2) and an outer ring (5) arranged at least indirectly in a bore (4) and radially between the inner ring (3) and the outer ring (5) rotatably disposed elastomeric element (6), wherein the bearing bush (1) is switchable between at least two stiffness levels, wherein the elastomeric element (6) has at least two directional stiffness levels and the stiffness change of the bearing bush (1) relative to the bore (4) and / or to the bolt (2) is rotatable, characterized in that radially between the inner ring (3) and the bolt (2) at least a first bearing element (7a) is arranged, wherein radially between the outer ring (5) and the bore (4) at least one second bearing element (7b) is arranged and the at least two bearing elements (7a, 7b) are designed as plain bearing bushes.

Description

The invention relates to a bearing bush for a motor vehicle, comprising an inner ring arranged at least indirectly on a pin and an outer ring arranged at least indirectly in a bore, and an elastomer element arranged rotationally fixedly between the inner ring and the outer ring, wherein the bearing bush is switchable between at least two rigidity stages.

Field of the invention

The structure and the resulting operating data of bearing bushes that are used in a chassis of a motor vehicle, greatly affect the driving and steering characteristics of the motor vehicle. Relatively small changes in the spring rate or stiffness of the bushings can have significant effects on vehicle characteristics such as understeer or oversteer, chassis noise, vibration, and running hardness. Depending on the setting of the bearing bush, the motor vehicle has a relatively "soft" or a relatively "hard" running behavior.

From the well-known prior art different bushings are known in the chassis area of a motor vehicle. On the one hand, purely mechanical bearing bushes or rubber mounts are known which have a defined rigidity. Furthermore, hydraulically damped suspension bushings with fixed or variable stiffness are known. In addition, bearings with magnetorheological fluids or magnetorheological elastomers are known, wherein the stiffness can be varied over a magnetic field.

For example, the DE 696 22 141 T2 a method of making and using a variable stiffness suspension bushing for controlling the relative movement between a suspension link in a motor vehicle and a frame member of the motor vehicle. The suspension sleeve has a variable rigidity which is realized by including a magnetorheological elastomer or gel whose stiffness is variably adjustable over a wide range by a controllable magnetic field. The variable controllable magnetic field is generated by means of an electromagnet structure, which as part of the structure is completely integrated in a suspension bushing structure.

The DE 10 2013 213 075 A1 describes a bearing bush for motor vehicles. which has an elastomeric bearing. The elastomeric ring of the elastomeric bearing is designed to be different stiff to the longitudinal direction of the vehicle.

The DE 37 19 327 A1 discloses a bushing which is formed as a rubber bushing. The rubber bushing has different spring constants, as are different in different angular positions.

From the DE 197 52 635 A1 is known a bearing bush for a motor vehicle, which supports a rubber insulator by means of a bearing in a cavity. By means of electromagnets, the rubber insulator can be twisted.

task

The object of the invention is to provide a particularly cost-effective and production-optimized bushing for a motor vehicle whose stiffness is mechanically adjustable and thus is not based on a hydraulic or magnetorheological action principle.

Inventive solution

According to the invention, the elastomer element has at least two direction-dependent rigidity stages and is rotatable relative to the bore and / or the bolt for changing the stiffness of the bearing bush. In other words, the stiffness of the elastomeric element changes depending on the position of the elastomeric member in the bore. For this purpose, the elastomer element is rotatable relative to the bore and / or the bolt. In particular, the at least two direction-dependent stiffness stages can be realized by different geometries and / or by different materials. Thus, both stiffening structures and / or materials and / or particles and / or fibers may be incorporated in the elastomeric member to stiffen at least a portion of the elastomeric member. Likewise, it is conceivable alternatively or additionally to introduce weakening structures and / or materials in the elastomer element, which weaken at least a part of the elastomer element and thus reduce the rigidity of the elastomer element. Insbesondre the elastomeric element is annular.

According to the invention, at least one first bearing element is arranged radially between the inner ring and the bolt, wherein at least one second bearing element is arranged radially between the outer ring and the bore. Alternatively, a sleeve is used between the bearing element and the bore, which can be pressed into the bore. Thus, the switchable suspension bearing can be mounted exactly as we, a conventional suspension bearings. According to the invention at least two bearing elements designed as plain bearing bushes. Furthermore, it is also conceivable to form the at least two bearing elements as a needle bearing.

Advantageously, the elastomer element has at least one end formed axially formed recess. The at least one recess serves as a weakening structure and reduces the rigidity of the elastomer element. Decisive are both the axial dimension and the geometric design and the radial and circumferential extent of the at least one recess. Preferably, the at least one recess extends from one end face over the entire axial dimension to the other end face of the elastomer element. Alternatively, two recesses are arranged axially between the two end faces and separated by a web arranged axially therebetween.

Furthermore, the elastomer element preferably has two, axially arranged recesses arranged on the end side, which are arranged radially opposite the elastomer element. Furthermore, the two recesses are formed identically. This results in a homogeneous distribution of the absorbed forces in the elastomer element.

The invention includes the technical teaching that the at least one recess has a circumferential extent on the elastomer element of at least 70 ° to at most 110 °. In other words, the at least one recess extends over at least about 19% up to about 31% of the end face on the circumference of the elastomer element. Under the circumference is to be understood that the respective recess on the end face is arranged radially inwardly offset along the circumference of the elastomeric element.

According to a preferred embodiment, the at least one recess is kidney-shaped. Other geometries are also conceivable.

Preferably, the at least one recess at least partially receives a complementary formed thereto element. In other words, located in the at least one recess, an element for stiffening the at least one recess. Thus, the rigidity of the bearing bush can be adjusted specifically via the respective element. Alternatively, it is also conceivable that the at least one recess is only filled with air in order to realize a low rigidity of the elastomer element.

Further preferably, at least the inner ring for the change in stiffness of the bearing bush is at least indirectly rotatable by an electric motor. The at least indirect drive of the inner ring allows the advantageous arrangement of the electric motor on the sprung axle carrier. Furthermore, it is also conceivable to drive the outer ring at least indirectly via the electric motor, in which case the arrangement of the electric motor preferably takes place on the suspension link.

Furthermore, a gear arrangement preferably connects the electric motor at least to the inner ring. Consequently, the gear arrangement is arranged between the inner ring and the electric motor. Depending on the embodiment, the gear arrangement may also be arranged between the outer ring and the electric motor.

Brief description of the drawing

Further measures improving the invention will be described in more detail below together with the description of preferred embodiments of the invention with reference to FIGS. Show it

1 3 is a perspective illustration of a suspension link for a motor vehicle, the suspension link having a bearing bush according to the invention,

2 a schematic sectional view illustrating the structure of a bearing bush according to the invention,

3a a schematic representation for illustrating a first position of the bearing bush according to the invention in the suspension arm,

3b a schematic representation for illustrating a second position of the bearing bush according to the invention in the suspension arm, and

4 a schematic sectional view illustrating the construction of the bearing bush according to the invention including gear assembly and electric motor.

Detailed description of the drawing

To 1 is a bearing bush according to the invention 1 in a designated hole 4 on a suspension handlebar 12 arranged. The suspension handlebar 12 is installed in a - not shown here - chassis of a - not shown here - motor vehicle. At the bolt 2 the bearing bush 1 is a - not shown here - axle carrier of the motor vehicle attached. Furthermore, the suspension handlebars 12 another hole 4a in which a mechanical, non-switchable bushing 1a is arranged. In other words, the bearing bush 1a designed as a conventional rubber bearing. At the bolt 2a the bearing bush 1a is a - not shown here - arranged wheel carrier.

According to 2 has the bearing bush according to the invention 1 one indirectly on the bolt 2 arranged inner ring 3 and one indirectly in the hole 4 the suspension handlebar 12 arranged outer ring 5 and a radially between the inner ring 3 and the outer ring 5 rotatably disposed elastomeric element 6 , The elastomer element 6 is annular and has two directional stiffness levels. To change the stiffness of the bearing bush 1 is the elastomer element 6 relative to the bore 4 and to the bolt 2 rotatable. These are radially between the inner ring 3 and the bolt 2 two bearing elements 7a . 7a ' arranged. Furthermore, radially between the outer ring 5 and the hole 4 another bearing element 7b arranged. All three bearing elements 7a . 7a ' . 7b are designed as plain bearing bushes.

The two directional stiffness levels of the elastomer element 6 are due to the targeted arrangement of two recesses each 8a . 8b and 8c . 8d in the respective end face 13a . 13b of the elastomeric element 6 realized. There are two recesses each 8a . 8b and 8c . 8d radially opposite to the elastomeric element 6 arranged and two recesses each 8a . 8c and 8b . 8d are axially opposite to the elastomeric element 6 arranged. Axial between the two axially opposite recesses 8a . 8c and 8b . 8d is a respective footbridge 14a . 14b educated. The recesses 8a - 8d thus lead to a weakening of the geometry of the elastomer element 6 and reduce the stiffness of the elastomeric element. For that, the respective recesses 8a - 8d arranged in the direction of the force. In other words, the respective force vector runs under the load of the bearing bush 1 preferably centrally through the recesses 8a - 8d therethrough.

According to the 3a and 3b are two frontally arranged, axially formed recesses 8a . 8b radially opposite to the elastomeric element 6 arranged. The two recesses 8a . 8b are kidney-shaped and extend circumferentially along the end face 13a of the elastomeric element 6 over an angle of 110 °. Thus, the circumference between the two recesses 8a . 8b an area with an angle of 70 ° formed as a solid material. Furthermore, the two recesses 8a . 8b from the one end face 13a axial to the other - not shown here - formed end face, wherein the respective recess 8a . 8b a complementary trained element 9a . 9b receives. The respective element 9a . 9b has a lower stiffness than the elastomer element 6 ,

According to 3a are the two recesses 8a . 8b of the elastomeric element 6 in the direction of the force vector 15 , so the force vector 15 centrally through the two recesses 8a . 8b runs. Thus, the stiffness of the bearing bush 1 relatively low, causing the vibration isolation of the bearing bush 1 is relatively high. Comfortable driving is thus supported.

In contrast, there are the two recesses 8a . 8b of in 3b illustrated elastomeric element 6 radially spaced from the force vector 15 , so the force vector 15 not through the two recesses 8a . 8b runs, but through the solid material of the elastomeric element 6 , Thus, the stiffness of the bearing bush 1 relatively high, reducing the damping of the bushing 1 is relatively low. A sporty driving style is thus supported.

To 4 is the inner ring 3 for changing the stiffness of the bearing bush 1 via a gear arrangement 11 from an electric motor 10 rotatable. Further, the electric motor 10 axially on a housing 16 the gear arrangement 11 arranged. About a pinion shaft 17 drives the electric motor 10 the gear arrangement 11 at. This meshes with the pinion shaft 17 with a ring gear 18 , wherein the ring gear 18 in one piece with a sun 19 is trained. Furthermore, the sun combs 19 with a stepped planetary set 20 that's about a bolt 21 with the inner ring 3 connected is. This is the inner ring 3 formed flange and at the same time there is a planet carrier. The inner ring 3 is rotatable about the two bearing elements 7a . 7a ' on the bolt 2 stored. Furthermore, the stepped planetary set meshes 20 also with one in the housing 16 trained, stationary fixed ring gear 22 , The elastomer element 6 is between the inner ring 3 and the outer ring 5 arranged rotationally fixed. Furthermore, the outer ring 5 via a bearing element 7b in a sleeve 23 rotatably mounted. The sleeve 23 is pressed into a - not shown here - hole. A rotation of the inner ring 3 thus simultaneously realizes a rotation of the elastomer element 6 and the outer ring 5 ,

LIST OF REFERENCE NUMBERS

1, 1a

bearing bush

2, 2a

bolt

3

inner ring

4, 4a

drilling

5

outer ring

6

elastomer element

7a, 7a ', 7b

bearing element

8a-8d

recess

9a, 9b

element

10

electric motor

11

transmission assembly

12

suspension arm

13a, 13b

face

14a, 14b

web

15

force vector

16

casing

17

pinion shaft

18

ring gear

19

Sun

20

Stepped planet set

21

bolt

22

ring gear

23

shell

Claims (8)

Bushing ( 1 ) for a motor vehicle, comprising one at least indirectly on a bolt ( 2 ) arranged inner ring ( 3 ) and one at least indirectly in a bore ( 4 ) arranged outer ring ( 5 ) and a radially between the inner ring ( 3 ) and the outer ring ( 5 ) rotatably disposed elastomeric element ( 6 ), the bearing bush ( 1 ) is switchable between at least two levels of rigidity, wherein the elastomeric element ( 6 ) has at least two direction-dependent stiffness levels and to the stiffness change of the bearing bush ( 1 ) relative to the bore ( 4 ) and / or to the bolt ( 2 ) is rotatable, characterized in that radially between the inner ring ( 3 ) and the bolt ( 2 ) at least one first bearing element ( 7a ) is arranged, wherein radially between the outer ring ( 5 ) and the bore ( 4 ) at least one second bearing element ( 7b ) is arranged and the at least two bearing elements ( 7a . 7b ) are designed as plain bearing bushes. Bushing ( 1 ) According to claim 1, characterized in that the elastomer element ( 6 ) at least one frontally arranged, axially formed recess ( 8a ) having. Bushing ( 1 ) according to claim 2, characterized in that the elastomeric element ( 6 ) two frontally arranged, axially formed recesses ( 8a . 8b ), which radially opposite to the elastomeric element ( 6 ) are arranged. Bushing ( 1 ) According to claim 2, characterized in that the at least one recess ( 8a ) a circumferential extent on the elastomer element ( 6 ) of at least 70 ° to at most 110 °. Bushing ( 1 ) according to claim 2, characterized in that the at least one recess ( 8a ) is kidney-shaped. Bushing ( 1 ) according to claim 5, characterized in that the at least one recess ( 8a ) at least partially a complementarily formed element ( 9a ). Bushing ( 1 ) according to claim 1, characterized in that at least the inner ring ( 3 ) to the stiffness change of the bearing bush ( 1 ) at least indirectly by an electric motor ( 10 ) is rotatable. Bushing ( 1 ) according to claim 7, characterized in that a gear arrangement ( 11 ) the electric motor ( 10 ) at least with the inner ring ( 3 ) connects.

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