DE20304481U1 - Elastic mounting has rigid frame as section of light metal extruded profile and spring arrangement elastically supporting via elastomer spring arms inside pocket in frame a bearing bush for dynamically stressed functional component - Google Patents

Abstract

The elastic mounting (1) has a rigid frame (2) and spring arrangement (4) of elastomer material mounted on the frame. The rigid frame is a section of light metal extruded profile, and the spring arrangement elastically supports via spring arms (6) of elastomer material (3) located inside a pocket in the frame a bearing bush (5) provided for a dynamically stressed functional component. The light metal profile may be an aluminum cast or extruded profile. Stops are formed for the bearing bush on the frame by sections of the light metal profile.

Description

Elastic bearing with a rigid frame and a spring arrangement made of elastomer material mounted on the frame

The invention relates to an elastic bearing with a rigid frame and a spring arrangement made of elastomer material mounted on the frame according to the preamble of claim 1.

An elastic self-aligning bearing in which a bearing bush for a dynamically loaded functional part is designed as a pivot bearing bush and in which another bearing bush designed as a pivot bearing bush is provided for a supporting component is known from DE 198 31 114 A1. The two pivot axes of the two pivot bearing bushes run parallel to each other. This

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enables static relative position changes of the dynamically loaded functional part relative to the supporting component with relative pivoting of the self-aligning bearing. The spring arrangement made of elastomer material engages the rigid frame with spring arms at the side and elastically supports the pivot bearing bush for the dynamically loaded functional part within a large recess in the frame at a distance from the boundaries of the recess. The frame serves as a loss protection for a bearing pin of the dynamically loaded functional part that engages in the pivot bearing bush. It also extends in the vertical direction from the spring arrangement made of elastomer material upwards to the pivot bearing bush for the supporting component. This height difference between the two pivot bearing bushes is therefore not overcome by elastomer material, which brings cost advantages when using high-quality silicone rubber, which may be necessary in environments with higher temperatures. The pivot bearing bush for the supporting component is formed in a closed ring of the frame made of elastomer material lining the ring. The entire rigid frame consists of a bent metal strip whose free ends interlock to form the closed ring. This rigid frame of the well-known elastic bearing proves to be expensive to manufacture despite its simple starting material. In addition, the possibilities for shaping it are limited and even when the metal strip is profiled, it does not have the dimensional rigidity that is often desired, for example, for defined lateral guidance perpendicular to the main extension plane of the well-known self-aligning bearing. There is also the risk of the frame opening accidentally if the ring of the interlocking free ends of the metal strip is pulled apart.

Another elastic self-aligning bearing is known from EP 0 908 345 A2. Here, the pivot bearing bush for the supporting component is arranged within the same recess in the frame as the spring arrangement made of elastomer material that supports the pivot bearing bush for the dynamically stressed functional part. The frame only has a single recess and consists of a tube section. The tube section used as a rigid frame has only limited functionality.

DE 197 48 824 A1 discloses an elastic pendulum bearing that largely corresponds to the previous state of the art, in which the simple ring-shaped frame is made of hard plastic, which is reinforced to a certain extent by its profiling, but is hardly really rigid. Moreover, it also has only limited functionality.

DE 100 19 643 A1 discloses an elastic bearing for suspending a dynamically loaded functional part, in which two pivot bearing bushes with pivot axes running parallel to one another are each embedded in a spring body made of elastomer material, which is surrounded in a ring shape by a common frame in two recesses spaced apart from one another. In order to elastically support the dynamically loaded functional part against a supporting component, the pivot bearing bushes are pivoted parallel to the common frame about axes running perpendicular to their pivot axis, whereby the spring bodies are deformed in the recesses of the rigid frame in order to apply the necessary support forces. The frame of this known elastic bearing is cast from metal. Specifically, a zinc die-cast alloy is mentioned. The dimensional rigidity and functionality of the frame of the known elastic bearing are high. However, its production costs are also high. In particular, the mold tool costs for injection molding tools are very high, which has an unpleasant impact on any changes to the frame, for example to achieve higher guide rigidity in certain directions.

From DE 196 54 189 A1, an elastic fixed bearing with the features of the preamble of claim 1 is known. A fixed bearing has a frame that is fixed in place. In the case of a rigid frame, the entire frame is fixed in place. A spring arrangement made of elastomer material is mounted within the frame, which elastically supports a bearing bush arranged within a recess in the frame for a dynamically stressed functional part. In contrast to the elastic bearings described so far, this fixed bearing is not specifically designed for mounting an exhaust system on the vehicle floor.

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of a motor vehicle, but it serves, for example, as an engine mounting base, suspension bearing bush, body mounting base or differential mounting base for a motor-driven motor vehicle. The rigid frame of the elastic fixed bearing, which is known from DE 196 54 189 A1, is designed as a section of a light metal extruded profile. The recess in which the bearing bush is supported by the spring arrangement relative to the frame is circular, i.e. it is delimited by a cylinder jacket section of the frame. The frame in the known elastic fixed bearing therefore does not have any special functionality. The spring arrangement of the known elastic fixed bearing is a rubber sleeve, the outer circumference of which is vulcanized to the frame and the inner circumference to the bearing bush. Although the functionality of the frame in the known elastic fixed bearing is only minimal, it must be further processed in order to form fastening points for its fixed attachment in addition to cutting a section of a light metal extruded profile to length. Specifically, mounting holes must be drilled for its permanent installation.

An elastic fixed bearing for mounting exhaust systems on the floor of motor vehicles is known, for example, from US 4,550,795. The softness of the elastic bearing required for vibration-isolating mounting of an exhaust system is also achieved in an elastic fixed bearing by spring arms between the frame, which can also be rigid here, and the bearing bush for the exhaust system. The rigid frame of the elastic fixed bearing known from US 4,550,795 is a metal bracket bent from solid material, open at the top, with fastening holes in both of its ends.

The invention is based on the object of providing an elastic bearing according to the preamble of claim 1, which is suitable for mounting an exhaust system on the vehicle floor of a motor vehicle and can be produced cost-effectively despite high performance.

According to the invention, this object is achieved by the elastic bearing with the features

of protection claim 1. Advantageous embodiments of the new elastic bearing are described in protection claims 2 to 10.

The rigid frame of the new elastic bearing is formed exclusively by cutting the section of the extruded light metal profile to length. To produce the rigid frame, it is actually sufficient to cut an extruded light metal profile to the length of the desired depth of the rigid frame. No further processing of the section of the extruded light metal profile is carried out, except perhaps deburring or cleaning. All the necessary functionalities of the frame are determined exclusively by the extruded light metal profile. Nevertheless, much more functionality can be achieved here than has previously been exploited in the state of the art of elastic bearings in the rigid frame. At the same time, the new elastic bearing is tailored to the special requirements of the suspension of an exhaust system on the floor of a motor vehicle thanks to the spring arms made of elastomer material with which the spring arrangement elastically supports the bearing bush for the dynamically stressed functional part within the recess against the rigid frame. The result is an elastic bearing that can be produced relatively inexpensively without compromising on the bearing's performance.

Light metal extruded profiles can be made very rigid even with a relatively low weight. The rigidity can be increased even further by using cross braces without this greatly increasing the manufacturing costs for the light metal extruded profile. The design freedom within the cross-sectional plane of the extruded profile also means that the rigid frame of the new bearing can be assigned a high level of functionality. Variations of these functionalities can also be implemented at relatively low cost. Typically, the cost of a new injection disk for the production of a light metal extruded profile is at least an order of magnitude lower than the cost of a new injection molding tool for three-dimensional injection molding. Profiling the frame of the new elastic bearing to further increase its rigidity turns out to be unnecessary.

The light metal extruded profile is typically an aluminum continuous cast or extruded profile. The exact alloy composition can be within the usual range.

Stops for the bearing bush can be formed on the frame by areas of the light metal extruded profile. For example, such a stop can be provided on an additional cross strut of the light metal extruded profile.

To make the new elastic bearing a self-aligning bearing, it can be provided that a second bearing bush for a supporting component is arranged within a second recess in the frame. This means that the frame then has at least two separate recesses for the two bearing bushes. This makes it possible to provide lateral guidance through the frame, particularly for the second bearing bush.

This also applies, for example, if the second bearing bush is formed by lining the second recess in the frame with elastomer material. This lining should be made thinner in the direction of the desired increased guide stability of the second bearing bush.

In this context, it is particularly preferred if the second recess is delimited by at least one second region of the frame, which neither defines the external dimensions of the frame, nor at the same time delimits a recess in the frame in which parts of the spring arrangement made of elastomer material are arranged. This region of the frame can thus be moved towards and away from the second bearing bush in order to adjust the guide stiffness for the second bearing bush, without this affecting other functionalities of the rigid frame. This can also be done within an unchanged vulcanizing tool for vulcanizing the spring arrangement made of elastomer material and other parts of the new elastic bearing made of elastomer material. This means that changes to the new elastic bearing are possible solely by changing the rigid frame, which can be achieved by modifying the injection disks used for this purpose.

can be implemented cost-effectively without incurring any new tooling costs anywhere else, even in the form of tool modification costs.

For an alternative implementation of the new elastic bearing as a fixed bearing, in which the rigid frame is to be provided for stationary storage, the frame can have a T-shaped groove on its outer circumference for the rotationally secure reception of a non-round head of a fastening element. The fastening element can be a fastening screw, for example. The fastening screw can have a conventional hexagonal screw head that can be inserted laterally into the T-shaped groove in a rotationally secure manner. However, it is preferred if the screw is a hammer head screw with rectangular dimensions. The T-shaped groove is in any case already formed by the light metal profile.

The frame can also have at least one guide web on its outer circumference in order to align it in a defined manner on a guide in an installation situation. For example, a guide web running parallel to the groove can be provided on both sides of the groove.

It is particularly preferred if a contact surface is formed on the outer circumference of the frame in the areas on both sides of the groove and if the frame is offset below the level of the contact surface between the contact surface and each guide web protruding above the contact surface. This offset of the frame can be filled with the elastomer material that also forms the spring arrangement and can also provide an anti-corrosive coating for the entire frame. The contact surface of the frame and the adjacent areas of the elastomer material between the guide webs thus define an overall contact area of the new elastic bearing, which makes it easy to ensure that the elastic bearing sits permanently without glare.

The invention is explained and described in more detail below using exemplary embodiments.

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Fig. 1 is a side view of a first embodiment of the bearing, with the position of an embedded rigid frame being shown in dashed lines,

Fig. 2 is an isolated side view of the rigid frame according to Fig. 1,

Fig. 3 is a perspective view of a second embodiment of the elastic bearing,

Fig. 4 is an isolated perspective view of the rigid frame of the elastic bearing according to Fig. 3 and

Fig. 5 is a perspective view of a fastening element for the rigid frame of the elastic bearing according to Fig. 3.

The elastic bearing 1 according to Fig. 1 has a rigid frame 2, shown separately in Fig. 2, which is completely embedded in elastomer material 3. The elastomer material 3 forms a spring arrangement 4, which elastically supports a pivot bearing bush 5, also made of elastomer material 3, against the rigid frame 2. The spring arrangement 4 has two spring arms 6 extending laterally from the pivot bearing bush 5, which engage the rigid frame 2. The pivot bearing bush 5 with a pivot axis 7 is intended for a bearing bolt of a dynamically stressed functional part, for example an exhaust system of a motor vehicle. Since increased temperatures occur in the area of such an exhaust system, the elastomer material 3 must be as thermally stable as possible. For this purpose, it is typically made of silicone rubber 8, which has the required thermal stability, but is comparatively expensive. The elastomer material 3 also forms a further pivot bearing bush 9 above the pivot bearing bush 5, the pivot axis 10 of which runs parallel to the pivot axis 7. The pivot bearing bush 9 serves to accommodate a bearing bolt of a supporting component, which is attached to the vehicle floor, for example, in order to suspend the exhaust system mentioned above. The elastic bearing 1 is designed as a

A pendulum bearing 11 is designed which can oscillate around the pivot axes 7 and 10 in order to compensate for thermal changes in the length of an exhaust system relative to the vehicle floor, for example. The design of the pivot bearing bushes 5 and 9 from elastomer material 3 ensures that bearing bolts with different outer diameters can be accommodated without play within a tolerance range. In particular, there are no relative movements of an inner surface of the pivot bearing bush relative to an outer surface of the respective bearing bolt.

The frame 2 shown separately in Fig. 2 has various functions in the elastic bearing 1 according to Fig. 1. For example, it serves as a loss protection device, which prevents the bearing pin arranged in the pivot bearing bush 5 from falling downwards even if the spring arrangement 4 fails, i.e. for example if one of the spring arms 6 breaks. The rigid frame 2 also has the function of bridging a height difference between the pivot bearing bushes 5 and 9 without using up much of the high-quality silicone rubber 8. The rigid frame 2 could also fulfill these two functions with its outer ring-shaped area 12 alone. The rigid frame 2 is given greater functionality by two cross struts 13 and 14. The upper cross strut 13 serves to limit a recess 15 in the frame, in which the elastomer material 3 forms the pivot bearing bush 9 according to Fig. 1. The course of the cross strut 13 can influence the rigidity of the lateral guidance of the pivot bearing bush 9 within the recess 15 in addition to the depth of the rigid frame 2 perpendicular to the plane of the drawing according to Fig. 2. This influence has no effect on other functionalities of the rigid frame 2, since the cross strut 13 does not simultaneously delimit a recess 16 in the frame 2 in which the spring arrangement 4 supports the pivot bearing bush 5 according to Fig. 1. Rather, there is a third recess 17 in the frame, which is partially delimited by the cross struts 13 and 14 and which has no direct function in the new pivot bearing. The cross strut 14 delimits the recess 16 in which, according to Fig. 1, the spring arrangement 6 elastically supports the pivot bearing bush 5, and it forms an upper stop 18 for the pivot bearing bush 5 in the recess 16. A

lower stop 19 is formed by the annular region 12 of the frame 2. The stops 18 and 19 are hard, i.e. non-buffered stops for the pivot bearing bush 5. However, this is not critical because the pivot bearing bush 5 itself is made of elastomer material 3 and thus automatically strikes the stops 18 and 19 softly. The complete embedding of the frame 2 in the elastomer material 3 according to Fig. 1 has less of a buffer function for the frame 2 than a corrosion protection function. The pear shape of the frame 2 according to Fig. 2 results from the coordination of its outer circumference, which corresponds to the course of its annular region 12, with the function of the elastic bearing 1 as a self-aligning bearing 11. The pivot bearing bush 9 in the recess 15 is the only thing that has to be located in the upper region of the elastic bearing 1. In this respect, the elastic bearing 1 can be kept narrow in its upper area. At the bottom, however, the spring arrangement 4 takes up lateral installation space. To produce the rigid frame 2 according to Fig. 2, an aluminum extruded profile 20 is produced using a spray disk, the initial cross section of which corresponds to a negative form of the cross section of the frame 2 shown in Fig. 2. This aluminum extruded profile is cut into sections 21, each of which corresponds to a rigid frame 2 according to Fig. 2. The cross section of the frame 2 can be varied by varying the spray disk without this incurring high costs. The variations can take place within the internal volume of a vulcanizing tool in which the elastomer material 3 is vulcanized to the frame 2 and in which changes typically result in costs that are an order of magnitude higher than changes to the spray disk for the extruded aluminum profile 20. No further processing of the extruded aluminum profile 20 or another light metal extruded profile other than cutting to length into sections 21 is carried out to produce the frame 2. This does not, of course, exclude deburring and/or cleaning of the sections 21.

The elastic bearing 1 shown in Fig. 3 is a fixed bearing 23 in which the rigid frame 2 is intended for stationary mounting. If the elastic bearing 1 is intended for mounting an exhaust system of a motor vehicle, the stationary mounting is carried out on the vehicle floor or on a support protruding from the vehicle floor. For stationary mounting, the

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Frame 2, which is shown separately in Fig. 4, has a T-shaped groove 24. The T-shaped groove 24 is intended to receive a head 30 of a fastening screw 29, which is shown in Fig. 5. The head 30 has rectangular dimensions and is received in the groove 24 in a rotationally secure manner, with the thread of the fastening screw 29 protruding from the frame 2. Guide webs 25 are provided on both sides of the groove 24, which protrude from the outer circumference of the frame as parts of the frame. The guide rods 25 run parallel to the groove 24. They were formed together with the groove 24 during the manufacture of the extruded aluminum profile 20. Immediately adjacent to the opening of the groove 24, the frame forms a contact surface 26 on its outer circumference, which in the elastic bearing 1 according to Fig. 3 is not covered, or only thinly covered, by the elastomer material 3. However, between the contact surface 26 and the guide webs 25, the outer circumference of the frame protrudes below the level of the contact surface 26, and this protrusion 27 is filled with elastomer material 3 in the elastic bearing 1 according to Fig. 3. This forms a contact area 28 which extends on both sides of the opening of the groove to the guide webs 25, which comprises a hard core area with the contact surface 26 and a softer adaptation area made of elastomer material 3 adjacent to it. The boundary of the groove 24 towards the recess 26 of the frame 2 forms the upper stop 18 for the bearing bush 22, which is provided in the elastic bearing 1 according to Fig. 3 to receive a fastening bolt of the functional part to be supported. The lower stop 19 is formed in the elastic bearings 1 according to Fig. 3 by an outward-directed bulge of the frame 2, against which the bearing bush 22 abuts flatly with its outer circumference when the working range of the elastic bearing according to Fig. 3 is exceeded. The type of support of the bearing bush 22 via spring arms 6 made of the elastomer material 3 against the rigid frame 2 in the fixed bearing 23 according to Fig. 3 corresponds to the support of the pivot bearing bush 5 against the frame 2 in the self-aligning bearing according to Fig. 1. The arrangement of the spring arms 6 could also be different in both cases. For example, four spring arms could be provided, which extend diagonally upwards and diagonally downwards on both sides of the bearing bush 22 or the pivot bearing bush 5. The spring arms do not necessarily have to be straight either. They can also have a curved or kinked course.

At least for the suspension of an exhaust system on the vehicle floor of a motor vehicle, it is not advantageous if the spring arms essentially only run in the direction of the main dynamic load on the elastic bearing, i.e. from top to bottom or from bottom to top, to the bearing bush for the dynamically loaded functional part.

1 - Warehouse

2 - Frame

3 - Elastomer material

4 - Spring arrangement

5 - Pivot bearing bush

6 - Spring arm

7 - Swivel axis

8 - Silicone rubber

9 - Pivot bearing bush

10 - Swivel axis

11 - Self-aligning bearing

12 - Area

13 - Cross brace

14 - Cross brace

15 - Recess

16 - Recess

17 - Recess

18 - Stop

19 - Stop

20 - Aluminium extruded profile

21 - Section

22 - Bearing bush

23 - Fixed bearing

24 - Groove

25 - Guide bar

26 - Contact surface

27 - Jump

28 - Investment area

29 - Fixing screw

30 - Head

Claims (10)

1. Elastic bearing with a rigid frame and a spring arrangement made of elastomer material mounted on the frame, wherein the rigid frame comprises a section of a light metal extruded profile and wherein the spring arrangement elastically supports a bearing bush arranged within a recess in the frame for a dynamically stressed functional part, characterized in that the rigid frame ( 2 ) is the cut section of the light metal extruded profile and that the spring arrangement ( 4 ) elastically supports the bearing bush ( 5 ) for the dynamically stressed functional part via spring arms ( 6 ) made of elastomer material ( 3 ) within the recess ( 16 ) relative to the rigid frame ( 2 ). 2. Bearing according to claim 1, characterized in that the light metal extruded profile is an aluminum extruded profile ( 20 ) or an aluminum extruded profile. 3. Bearing according to claim 1 or 2, characterized in that stops ( 18 , 19 ) for the bearing bush ( 5 ) on the frame ( 2 ) are formed by regions of the light metal extruded profile ( 20 ). 4. Bearing according to one of claims 1 to 3, characterized in that a second bearing bush ( 9 ) for a supporting component is arranged within a second recess ( 15 ) in the frame ( 2 ). 5. Bearing according to claim 4, characterized in that the second bearing bush ( 9 ) is formed by lining the second recess ( 15 ) in the frame ( 2 ) with elastomer material ( 3 ). 6. Bearing according to claim 5, characterized in that the second recess ( 15 ) is delimited by at least one region ( 13 ) of the frame ( 2 ) which neither defines the external dimensions of the frame ( 2 ) nor simultaneously delimits a recess ( 16 ) in the frame ( 2 ) in which parts of the spring arrangement ( 4 ) made of elastomer material ( 3 ) are arranged. 7. Bearing according to one of claims 1 to 3, characterized in that the frame ( 2 ) has a T-shaped groove ( 24 ) on its outer circumference for the rotationally secure reception of a non-round head ( 30 ) of a fastening element. 8. Bearing according to one of claims 1 to 3 and 7, characterized in that the frame ( 2 ) has at least one guide web ( 25 ) on its outer circumference. 9. Bearing according to claims 7 and 8, characterized in that a guide web ( 25 ) running parallel to the groove ( 24 ) is provided on both sides of the groove ( 24 ). 10. Bearing according to claim 9 or claims 7 and 8, characterized in that a contact surface ( 26 ) is formed on the outer circumference of the frame ( 2 ) in the areas on both sides of the groove ( 24 ) and that the frame ( 2 ) has a projection ( 27 ) below the level of the contact surface ( 26 ) between the contact surface ( 26 ) and each guide web ( 25 ) projecting beyond the contact surface ( 26 ), which projection is filled with elastomer material ( 3 ).