DE19748824B4 - Elastic self-aligning bearing, in particular for suspending an exhaust system on a vehicle floor - Google Patents

Abstract

Elastic self-aligning bearing, in particular for suspending an exhaust system on a vehicle floor, with two swivel bearing bushes arranged within a loop-shaped loss protection device for receiving a supporting fastening element on the one hand and a fastening element to be supported on the other hand, the swivel bearing bushing for the supporting fastening element being arranged on the upper edge of the loss protection device and supporting it, wherein the pivot bearing bush for the fastener to be supported is arranged at a distance from the lower edge of the captive device and is supported by a spring arrangement made of elastomer material, which has spring arms which extend on both sides of a spring direction running through both pivot bearing bushes, between the pivot bearing bush for the fastener to be supported and the loss protection , and being a frame made of hard plastic, which is in normal operation of the self-aligning bearing (1) in comparison not significantly deformed to the spring arms, the loop-shaped captive device forms, characterized in that on each side of the spring direction (9) running through both pivot bearing bushes (2 and 3) there are two spring arms (11 and 13, 12 and 14) arranged one above the other between the pivot bearing bush ...

Description

The invention relates to a elastic self-aligning bearing, in particular for suspending an exhaust system a vehicle floor, according to the preamble of claim 1.

The exhaust system of a motor vehicle must be elastic be hung on the vehicle floor of the motor vehicle, on the one hand Do not transfer vibrations from the exhaust system directly to the rest of the vehicle and, on the other hand, thermal expansion of the exhaust system possible relative to the vehicle floor is. With a self-aligning bearing, the expansion of the exhaust system becomes relative to the vehicle floor, d. H. parallel to this, by a swiveling movement of the self-aligning bearing is compensated for by the two fastening elements. This also increases the Distance between the two swivel bearing bushes of the self-aligning bearing in the Zero its dynamic load. Depending on The spring characteristic of the self-aligning bearing can thereby dampen the vibration Greatly change the properties of the self-aligning bearing. This is especially true with a big one progressiveness the spring characteristic. It is therefore desirable that the changes in distance the pivot bearing bushes due to thermal expansion of the Exhaust system within a range of the spring characteristic with less progressiveness play.

An elastic self-aligning bearing for suspending an exhaust system on a vehicle floor, with two swivel bearing bushes arranged within a loop-shaped loss protection device for receiving a supporting fastening element on the one hand and a fastening element to be supported on the other hand, the swivel bearing bushing for the supporting fastening element being arranged on the upper edge of the loss protection device and supporting it and whereby the pivot bearing bush for the fastener to be supported is arranged at a distance from the lower edge of the captive device and is supported by a spring arrangement made of elastomer material is from the DE 30 34 370 C2 known. The loss prevention of this known self-aligning bearing is formed by a tear-resistant insert in an annular body made of elastomer material. The annular body is formed in one piece with a pivot bearing bush arranged on its upper edge for receiving a supporting fastening element. Within the annular body, a vertical web made of elastomeric material hangs down from the pivot bearing bush for the supporting fastening element and elastically supports at its free end a second pivot bearing bush for a fastening element to be supported. The web and the second pivot bearing bush are also formed in one piece with the annular body. The spring characteristic of the known self-aligning bearing initially has a low progressivity, ie a slight slope, as long as the spacing of the two swivel bearing bushes only expands the web made of elastomer material between the two swivel bearing bushes. As soon as the pivot bearing bush for the fastener to be supported strikes the lower edge of the annular body, the progressivity of the spring characteristic of the self-aligning bearing increases. The then larger slope of the spring characteristic is due to the additional counterforce of the annular body against an increase in the distance between the two pivot bearing bushes. The known self-aligning bearing has basically favorable spring and insulation properties for suspending an exhaust system on a vehicle floor. It is disadvantageous, however, that the elastomer material in the known self-aligning bearing is essentially subjected to tension. As is known, a tensile load leads relatively quickly to damage and then to destruction of the elastomer material, which results in only a comparatively short service life of the known self-aligning bearing. In addition, in the known self-aligning bearing, thermal expansion of the exhaust system with respect to the vehicle floor does not lead equally and reliably to pivoting of the self-aligning bearing around the two swivel bearing bushes. Rather, the pivot bearing bush is first deflected laterally at the free end of the vertical web within the annular body until it abuts the annular web. Only then will the entire self-aligning bearing be pivoted. However, the pendulum bearing may have been damaged beforehand by friction between the pivot bearing bush for the fastening element to be supported and the annular body. At least such damage occurs with repeated friction of the pivot bearing bush for the fastening element to be supported on the annular body.

An elastic self-aligning bearing, which differs from the preamble of claim 1 in that no frame made of a hard plastic is provided, which forms the loop-shaped captive device, is from the DE 44 06 729 A1 known. This elastic self-aligning bearing differs from the previously described prior art in that no tear-resistant insert is provided in the outer annular body made of elastomer material. Furthermore, there is an inner annular body made of elastomer material in the outer annular body, the pivot bearing bush for the fastening element to be supported being arranged at the upper edge and the pivot bearing bush for the fastening element to be supported being arranged at the lower edge of the inner ring. The two rings are made of rubber or plastic with un Different elasticity formed, wherein the outer ring has a larger spring constant than the inner ring and is thus assigned to the coarse vibrations. The arrangement of the two interlocking rings in the known elastic self-aligning bearing ensures that parts of the spring arrangement made of elastomeric material extend between the two pivot bearing bushes on both sides of a spring direction running through both pivot bearing bushings. As with the last-described prior art, these parts of the spring arrangement are only subjected to tension, which affects their service life, and they do not lead to a reliable pivoting of the self-aligning bearing when lateral forces occur before the pivot bearing bush for the fastener to be supported on the outer ring strikes.

One out of the DE 692 013 97 T2 Known elastic self-aligning bearing differs from the preamble of claim 1 in that the loop-shaped anti-loss device is made of welded metal. Spring arms extend laterally to the spring direction from the pivot bearing bush made of elastomer material for the fastening element to be supported up to the securing against loss. The pivot bearing bush for the fastener to be supported rests on a stop made of elastomer material in the basic position of the known elastic self-aligning bearing against a stop which is formed in one piece with the pivot bearing bush for the supporting fastener, which is also made of elastomer material.

From the US 4 81 7 909 (= EP 0 320 088 A1 ) an elastic self-aligning bearing is known in which an anti-loss device forms two eyelets and a web-shaped central region. A swivel bearing bush for a supporting fastening element is formed in one eyelet. In the other eyelet, a pivot bearing bush for a fastening element to be supported is elastically supported via two pairs of side spring arms made of elastomer material.

With simple elastic self-aligning bearings, such as those from the DE-OS 1 505 498 are known, a thermal expansion of the exhaust system relative to the vehicle floor leads very quickly to the fact that the distance between the pivot bearing bushes reaches an area with high progressivity of the spring characteristic, in which good vibration insulation by the self-aligning bearing no longer takes place.

Even with one from the EP 0 529 250 A1 Known elastic self-aligning bearing, which has the features of the preamble of claim 1, a thermal expansion of the exhaust system relative to the vehicle floor leads to the fact that the distance between the pivot bearing bushes reaches an area with high progressivity of the spring core line. The spring arms here extend obliquely downwards from the pivot bearing bush for the fastening element to be supported to the frame made of hard plastic which forms the captive device.

Another type of elastic bearings for fastening dynamically stressed functional parts, in particular of exhaust systems to a vehicle floor, is for example from the DE 34 45 491 C1 known. Such an elastic bearing has a base plate which is provided for rigid attachment to the vehicle floor and to which a holding bracket is fastened. A bearing bush is provided within the mounting bracket for receiving a fastening element to be supported, spring arms for elastic support of the mounting bush being provided between the mounting bush and the base plate on the one hand and the mounting bracket on the other hand. The spring arms absorb vertical dynamic loads on the exhaust system in relation to the vehicle floor, whereby good vibration damping properties are achieved. The spring arms between the base plate and the bearing bush have a curvature and are weaker than the spring arms arranged underneath between the bearing bush and the retaining bracket. Nevertheless, there is a noticeable tensile load on the upper spring arms, which limits the service life of the known elastic bearing. In addition, the spring arms must also compensate for the thermal expansion of the exhaust system with respect to the vehicle floor within the holding bracket which is rigidly designed here.

From the DE 42 11 397 C1 An elastic bearing of the basic type described last is known, in which the holding bracket is designed to be elastic in order to create an additional compensation option for the thermal expansion of the exhaust system with respect to the vehicle floor.

From the DE 195 00 192 C1 it is also known in an elastic bearing with an elastic retaining bracket to articulate the retaining bracket at both ends of the base plate in order to further facilitate lateral movement of the bearing bush relative to the base plate to compensate for thermal expansion of the exhaust system relative to the vehicle floor.

In the DE 195 00 191 C1 describes the possibility of attaching a retaining bracket made of elastomer material to the base plate with a tear-resistant insert and supporting the bearing bush with the spring arms within this retaining bracket. This also increases the lateral mobility of the bearing bush relative to the base plate.

With every elastic bearing the last described basic type occurs however a considerable deformation of the Bearing due to a thermal expansion of the exhaust system compared to the Vehicle floor on that inevitably to impair the vibration-damping Properties of the elastic bearing leads.

The invention is based on the object to show elastic self-aligning bearings of the type described at the outset, with excellent vibration-damping properties with an enlargement of the Distance between the two pivot bearings, for example by thermal expansion of an exhaust system compared to one Vehicle floor that has a particularly long service life, and yet economical can be produced.

According to the invention, this object is achieved by a elastic spherical bearing solved with the features of claim 1. at the new self-aligning bearing is provided with a frame made of hard plastic, which is the loop-shaped Loss prevention training. This frame made of hard plastic is relatively rigid and does not provide a second spring for the Self-aligning bearing provided. Although it has a certain elasticity due to its open form, but this is during normal operation of the elastic bearing meaningless.

The new elastic self-aligning bearing shows side spring arms on. The side arrangement of the spring arms has a double function. Firstly, it ensures that a tensile load the spring arms with dynamic loads on the elastic self-aligning bearing is only slight or even disappears completely. On the other hand, the lateral arrangement of the spring arms also ensure that the self-aligning bearing is pivoted about the two fasteners when, for example opposite an exhaust system expands a vehicle floor. This eliminates the risk of being destructive Friction between the pivot bearing bush for the fastener to be supported and the protection against loss. The rigidity of side spring arms, which with an elastic bearing with rigid to the vehicle floor fixing base plate is a hindrance because it compensates the thermal expansion of the exhaust system against the vehicle floor is impeded, is not only harmless with the new self-aligning bearing, but also it is used in two ways.

The spring arms extend transversely to the spring direction running through both pivot bearing bushes. Cross means that the Extension extends essentially perpendicular to the spring direction. there it is not a question of exactly maintaining an angle of 90 ° between the extension of the spring arms and the spring direction. For example can the lower spring arms fall down from the swivel bearing bush, a tensile load due to dynamic loads on the self-aligning bearing preferably To be largely avoided, the upper spring arms each have a curvature have, which is directed upwards. Until the curvature of the upper spring arms is eliminated by extension of the spring arms occurs no significant tensile load on the spring arms.

To the frame made of hard plastic can the spring arms can be vulcanized directly. At the same time, both the swivel bearing bush for the one to be supported Fastening element consist entirely or partially of elastomer material and in this respect in one piece be formed with the spring arms, as well as the pivot bearing bush for the supporting fastener consist entirely or partially of elastomer material and also vulcanized directly onto the frame. Here is the entire self-aligning bearing can be produced using a process known as K + K technology. Suitable as an elastomer material for the pivot bearing bushes and the spring arms are particularly high quality Silicone rubbers. Of this, however, only comparatively small quantities are used for the new one Self-aligning bearing with the frame made of hard plastic needed.

The swivel bearing bush for the fastener to be supported can basically relatively close to the pivot bearing bush for the fastener to be supported be arranged. However, a distance between the two pivot bearing bushes is preferred, to cheap leverage ratios for a Swiveling the self-aligning bearing around the two fastening elements for example in the case of thermal expansion of an exhaust system compared to one To create vehicle floor. Furthermore allows the distance when using the self-aligning bearing also a vibration-insulated movement of the two fasteners towards each other.

With the new self-aligning bearing, the swivel bearing bushes can be made entirely of elastomer material. But you can also have an inner lining made of another material or consist entirely of a metal sleeve, for example.

The invention is illustrated below of an embodiment explained in more detail and described. It shows:

1 a top view of the self-aligning bearing and

2 a longitudinal section through the self-aligning bearing.

That in the 1 and 2 reproduced self-aligning bearings 1 has two pivot bearing bushes 2 and 3 on. The swivel bearing bushes 2 and 3 have circular fre cross sections 4 and 5 to accommodate fasteners, not shown here. The upper swivel bearing bush serves here 2 to accommodate a supporting fastener while the lower pivot bearing bush 3 is provided for receiving a fastener to be supported. The fasteners, not shown, are in the pivot bearing bushes 2 and 3 about swivel axes 6 and 7 opposite the self-aligning bearing 1 pivotable. At the same time, the self-aligning bearing supports 1 the fastener to be supported in the swivel bearing bush 3 elas table on the supporting fastener of the swivel bearing bush 2 from. For this purpose, the two swivel bearing bushes 2 and 3 within a frame 8th arranged. The swivel bearing bush 2 is at the top of the frame 8th arranged and supports this. The swivel bearing bush 3 becomes opposite the frame 8th by spring arms 11 to 14 supported. Two upper spring arms are provided 11 and 12 and two lower spring arms 13 and 14 , with both the upper spring arms 11 and 12 as well as the lower spring arms 13 and 14 symmetrical to a spring direction 9 of the self-aligning bearing 1 are formed, which are perpendicular through the pivot axes 6 and 7 runs. The upper spring arms 11 and 12 and the lower spring arms 13 and 14 each run across the direction of the spring 9 , with the lower spring arms 13 and 14 are aligned perpendicular to this. The upper spring arms 11 and 12 are on average also approximately perpendicular to the spring direction 9 oriented, but they have curvatures pointing upwards 15 and 16 on. The spring arms allow the distance between the swivel axes to be changed 6 and 7 the swivel bearing bushes 2 and 3 with low progressivity of the counterforce of the self-aligning bearing 1 , So the self-aligning bearing 1 For example, compensate the thermal expansion of an exhaust system of a motor vehicle mounted on a vehicle floor in the horizontal direction by the self-aligning bearing 1 compared to the fasteners not shown here, the pivot axes 6 and 7 pivoted and the distance between the pivot axes 6 and 7 enlarged without the area of a flat spring characteristic of the self-aligning bearing 1 is left. A sufficiently good vibration insulation by the self-aligning bearing is only within this flat area of the spring characteristic 2 reached. The lateral arrangement of the spring arms 11 to 14 especially avoids the stress on the spring arms 11 to 14 on train when the distance between the swivel axes changes 6 and 7 the swivel bearing bushes 2 and 3 , In this context there are also the curvatures 15 and 16 the upper spring arms 11 and 12 important because they have a greater overall length of the upper spring arms 11 and 12 revealed when they used to bridge the distance between the frames 8th and the swivel bearing bush 3 in the zero position of the self-aligning bearing 1 would be required. The excess length of the spring arms 11 and 12 provides a reserve when the distance between the swivel axes increases 6 and 7 the swivel bearing bushes 2 and 3 Before this reserve is not completely used up, there is no significant tensile stress on the upper spring arms 11 and 12 on. The lower spring arms 13 and 14 are mostly exposed to a pressure-push load due to their arrangement. The spring arms 11 to 14 consist of an elastomer material 10 , especially a silicone rubber that is attached to the frame 8th made of hard plastic 17 is vulcanized. At the same time, the elastomer material forms 10 also the swivel bearing bush 3 to accommodate the fastener to be supported, but not shown here. It is also made of the elastomer material 10 the swivel bearing bush 2 designed to accommodate the supporting fastener, also not shown here, the elastomeric material 10 in turn directly on the frame 8th made of hard plastic 17 is vulcanized. On both sides of the swivel bearing bush 2 are additional stabilizations 18 and 19 in one piece with the swivel bearing bush 2 made of the elastomer material 10 trained and attached to the frame 8th made of hard plastic 17 vulcanized. The frame 8th made of hard plastic 17 has stiffening struts 20 on and is compared to the elasticity of the spring arms 11 to 14 not significantly deformable. In addition to mediating the support, it serves between the swivel bearing bush 2 and the spring arms 11 to 14 as protection against loss for the two fastening elements, if the elastomer material of the self-aligning bearing 1 should be destroyed. Under normal operating conditions, however, this does not occur within the normal lifespan of motor vehicles.

At the self-aligning bearing 1 is the swivel bearing bush 3 for the fastener to be supported at a distance from the swivel bearing bush 2 arranged for the supporting fastener to favorable lever ratios for pivoting the self-aligning bearing 1 about the pivot axes 6 and 7 To provide so that there is no lateral stress on the self-aligning bearing. In addition, this distance also allows a vibration-insulated approach of the two pivot bearing bushes 2 and 3 ,

1

aligning bearing

2

Pivot bushing

3

Pivot bushing

4

free cross-section

5

free cross-section

6

swivel axis

7

swivel axis

8th

frame

9

spring direction

10

Elastomer material

11

spring arm

12

spring arm

13

spring arm

14

spring arm

15

curvature

16

curvature

17

plastic

18

stabilization

19

stabilization

20

Versteifungsstrebe

Claims (5)

Elastic self-aligning bearing, in particular for suspending an exhaust system on a vehicle floor, with two swivel bearing bushes arranged within a loop-shaped loss protection device for receiving a supporting fastening element on the one hand and a fastening element to be supported on the other hand, the pivot bearing bushing for the supporting fastening element being arranged on the upper edge of the loss protection device and supporting it, wherein the pivot bearing bush for the fastener to be supported is arranged at a distance from the lower edge of the captive device and is supported by a spring arrangement made of elastomer material, which has spring arms which extend on both sides of a spring direction running through both pivot bearing bushes, between the pivot bearing bush for the fastener to be supported and the loss protection , and a frame made of hard plastic, which is in normal operation of the self-aligning bearing ( 1 ) not significantly deformed in comparison to the spring arms, which forms a loop-shaped captive device, characterized in that on both sides of the two pivot bearing bushes ( 2 and 3 ) running spring direction ( 9 ) two spring arms arranged one above the other ( 11 and 13 . 12 and 14 ) between the swivel bearing bush ( 3 ) for the fastener to be supported and the captive device and that the respective upper spring arms ( 11 and 12 ) an upward curvature ( 15 respectively. 16 ) exhibit. Self-aligning bearing according to claim 1, characterized in that the spring arms ( 11 to 14 ) directly to the frame ( 8th ) are vulcanized. Self-aligning bearing according to one of claims 1 and 2, characterized in that the pivot bearing bush ( 3 ) for the fastener to be supported at a distance from the swivel bearing bush ( 2 ) is arranged for the supporting fastener. Self-aligning bearing according to one of claims 1 to 3, characterized in that the pivot bearing bush ( 3 ) for the fastening element to be supported completely or partially made of elastomer material ( 10 ) exists and in this respect in one piece with the spring arms ( 11 to 14 ) is trained. Self-aligning bearing according to one of claims 1 to 4, characterized in that the pivot bearing bush ( 2 ) for the supporting fastening element made entirely or partially of elastomer material ( 10 ) exists and directly to the frame ( 8th ) is vulcanized.