WO2000013926A1

WO2000013926A1 - Elastic bearing

Info

Publication number: WO2000013926A1
Application number: PCT/EP1999/006268
Authority: WO
Inventors: Hartmut Brill
Original assignee: Wegu Gummi- Und Kunststoffwerke Gmbh & Co. Kg
Priority date: 1998-09-09
Filing date: 1999-08-26
Publication date: 2000-03-16
Also published as: DE19840889B4; DE19840889A1

Abstract

The invention relates to an elastic bearing (1), especially for suspending a exhaust system on a vehicle floor. The inventive bearing has a ring-shaped retaining bracket (2), fixing eyelets (14) for mounting the retaining bracket in a fixed position and a spring body (4) consisting of an elastomer material (5) which is mounted on the retaining bracket (2)and which elastically supports a bearing bush (6) for a fixing element to be supported, inside the retaining bracket (2). The retaining bracket (2) is produced from a one-piece section (3) of a metal wire (16) which also forms the fixing eyelets (14) for mounting the retaining bracket (2) in a fixed position.

Description

Elastic bearing

The invention relates to an elastic bearing, in particular for suspending an exhaust system on a vehicle floor, with an annular retaining bracket, with fastening eyelets for fixed attachment of the retaining bracket and with a spring body made of elastomer material, which is mounted on the bracket and a bearing bush within the bracket elastically supported for a fastener to be supported.

An elastic bearing for suspending an exhaust system on a vehicle floor should support the exhaust system softly so that vibrations of the exhaust system are not transmitted to the vehicle floor. Furthermore, the elastic bearing must compensate for vertical movements between the exhaust system and the vehicle floor, which are based on vertical vibrations of the entire vehicle. At the same time, the elastic bearing also has to accommodate horizontal relative displacements between the exhaust system and the vehicle floor when the exhaust system expands thermally or shifts horizontally, for example due to engine movements. Tolerances in the exhaust system relative to the vehicle floor must also be bridged. The elastic bearing is exposed to high temperatures through the exhaust system, so that, for example, only very high-quality silicone rubbers can be used for the spring body made of elastomer material, and the elastic bearing is located on the vehicle floor in an exposed position, in which it is exposed to aggressive salt water, for example in winter can come into contact. Another aspect is the security against loss guaranteed by the elastic bearing for the exhaust system. Even if the spring body made of elastomer material is destroyed, the retaining bracket must reliably prevent the fastening element to be supported from falling. All of the above requirements are against the background of considerable cost pressure, which affects all motor vehicle parts.

An elastic bearing of the type described above is known from DE 195 00 192 Cl. The bracket is formed by a horseshoe-shaped spring steel band section, which is hinged with its two free ends to a base plate. the base plate forms the upper horizontal region of the holding bracket and has in its free ends fastening holes for screwing the elastic bearing onto a vehicle floor. In the known elastic bearing, the spring body made of elastomer material is injection molded onto the metal retaining bracket, forming a rubber-metal connection. The elastomer material covers the entire bracket with a corrosion protection layer. The spring body has upper and lower spring arms between the retaining bracket and the bearing bush for the fastening element to be supported. A disadvantage of the known elastic bearing is that its bracket is complex to manufacture due to the multi-part structure. In particular in the area of attaching the free ends of the spring steel strip section to the base plate, considerable effort must be made so that no undesired detachment can take place here. The corrosion protection layer made of the elastomer material in the known elastic bearing consumes not inconsiderable amounts of elastomer material. This is particularly disadvantageous when it comes to high-quality silicone rubber, which, however, cannot readily be replaced by less expensive elastomer materials when the elastic bearing is thermally stressed. The known elastic bearing also proves to be sensitive to loads perpendicular to its main extension plane, such as those that can occur, for example, due to unavoidable tolerances between the exhaust system and the vehicle floor. From US 5 817 909 an elastic bearing is known, which is designed as a so-called self-aligning bearing. A self-aligning bearing has two bearing bushes, one bearing bushing being provided for fastening the self-aligning bearing and the other bearing bushing running parallel to the one bearing bushing and being elastically supported relative to the latter. The self-aligning bearing can be pivoted both with respect to a bearing pin in one bearing bush and with respect to a bearing pin in the other bearing bush. The elastic self-aligning bearing known from US Pat. No. 4,817,909 has a base body made of elastomer material, in which a one-piece section of a metal wire is embedded, which serves to reinforce the base body and also to prevent loss. This means that the metal wire surrounds both the first and the second bearing bush in a loop. The second bearing bush is elastically supported in an annular area of the base body through which the metal wire runs, via spring arms running approximately horizontally.

Another elastic self-aligning bearing is known from FR 27 45 242. In this elastic self-aligning bearing, a base body made of elastomer material is provided, a bent part made of a one-piece section of a metal wire running through recesses in and around the base body in such a way that a stop for the relative movement of the two bearing bushes and also a captive device is formed. Apart from the mutual adaptation in the outer shape, in which the bent part engages around the base body in a form-fitting manner, there is no connection between the base body made of elastomer material and the bent part made of metal wire.

The invention has for its object to show an elastic bearing of the type described above, which is inexpensive to manufacture and at the same time has a long service life and operational reliability.

According to the invention, this object is achieved with an elastic bearing of the type described in the introduction in that the holding bracket is formed from a one-piece section of a metal wire, which also forms the fastening eyelets for the fixed attachment of the bracket.

The bracket of the new elastic bearing is formed from a one-piece section of a metal wire. The resulting one-piece design of the entire retaining bracket makes it not only inexpensive to manufacture, but also extremely reliable in terms of securing against loss for the fastening element to be supported. The design freedom for bent wire parts made of metal wire is known in principle and is completely sufficient for the design of the retaining bracket for the new elastic bearing. There are even new freedoms in the shape of the bracket of the new elastic bearing, for example for its adaptation to cramped installation conditions in certain types of motor vehicles.

The metal wire for the holding bracket can have a round, a rounded or a flattened cross section. Since the elastomer material typically surrounds the metal wire in the new elastic bearing in order to connect it to the only narrow contact area on the inside of the holding bracket, an at least rounded cross section of the metal wire, from which no notching effect on the elastomer material is preferred.

Because the elastomer material of the spring body surrounds the metal wire in a ring in the new elastic bearing, it does not necessarily have to be vulcanized onto the metal wire. Rather, the elastomer material can also enclose the metal wire without forming a rubber-metal connection. The new elastic bearing then detaches itself even further from the known structure with a retaining bracket made of flat material and delimiting the spring body. Flat material is preferred for the injection molding of the spring body with the formation of a rubber-metal connection because of the particularly large contact area on the inside of the holding bracket, the formation of a rigid holding bracket but is more complex than when using metal wire. If, in the new elastic bearing, the elastomer material surrounds the metal wire with a rounded cross section without forming a rubber-metal connection, the elastomer material can also move at the interface with the metal wire with respect to the metal wire. The connection is then not made via an adhesive surface but only in the manner of a loop.

The new elastic bearing without the formation of a rubber-metal connection between the bracket and the spring body gives additional freedom with regard to the surface of the metal wire, which does not have to be suitable for the formation of a rubber-metal connection. In use, it also turns out to be a particular advantage that the effective length of the spring body made of elastomer material between the bearing bush for the fastening element to be supported and the holding bracket is significantly greater in the case of tensile loads than in the case of compressive loads, since the spring body rests on the inside of the holding bracket when subjected to pressure loads, with tensile loads but is supported on the outside of the bracket. As a result, an undesirable tensile stress on the elastomer material of the spring body is significantly reduced and the service life of the elastic bearing is therefore fundamentally increased overall. The rounded cross section of the metal wire not only ensures that the spring body made of elastomer material can move relative to the metal wire without damage in the main extension planes of the elastic bearing. It also enables a certain relative movement of the spring body made of elastomer material from the main extension plane of the retaining bracket, the spring body twisting somewhat around the metal wire. Tolerances in this direction can be compensated for between a vehicle floor and an exhaust system.

In the new elastic bearing without a rubber-metal connection between the elastomer material and the retaining bracket, the surface of the metal wire is preferably smooth. However, it does not have to be polished or chrome-plated, for example to enable described relative movements. There should only be no abrasion between the spring body made of elastomer material and the metal wire.

The metal wire of the new elastic bearing must be protected against corrosion. This means that it itself must be corrosion-resistant or have a corrosion-resistant coating. This gives relatively great freedom, since no rubber-metal connection has to be made with the elastomer material of the spring body or an existing rubber-metal connection typically does not represent the only connection of the elastomer material to the retaining bracket. For cost reasons, a metal wire that is itself surface-coated with a metal or a metal compound is preferred.

The metal wire for the bracket can be a spring steel wire. However, the retaining bracket is generally not intended to be made into a secondary spring of the elastic bearing downstream of the spring body made of elastomer material. Rather, the stiffness of the bracket should be so great compared to the stiffness of the spring body made of the elastomer material that it does not deform appreciably elastically during normal operation of the elastic bearing. That all relevant deformations take place in the elastomer material.

The metal wire can form the fastening eyelets for the stationary attachment of the holding bracket in such a way that they are bent upward relative to an upper horizontal region of the holding bracket. Due to the offset, the fastening eyelets do not hinder the connection of the spring body in the upper horizontal area of the holding bracket. The fastening eyes do not necessarily have to be closed for the secure attachment of the retaining bracket to a vehicle floor.

The one-piece section made of the metal wire can be bent to the holding bracket in such a way that the metal wire in an upper horizontal region of the holding bracket two side by side lying upper tracks and in a lower horizontal area has a lower track running in the vertical projection in the middle between the two upper tracks. This means that the bracket has a double upper base and is otherwise simple in terms of the metal wire used. Even if the spring body made of elastomer material in the upper horizontal region of the retaining bracket encloses both tracks of the spring wire, there is still the possibility that the bearing bush is laterally displaced from the main extension plane of the retaining bracket to bridge tolerances. If, however, a particularly stable support of the bearing bush relative to the lower horizontal region of the holding bracket is to be achieved with respect to lateral influences, the metal wire can also be bent such that it forms a track in the upper horizontal area of the holding bracket and otherwise two tracks arranged side by side. However, the last variant has the disadvantage that it is less suitable for the injection molding of the spring body made of elastomer in a two-part mold. To limit the parts of the spring body made of elastomer material surrounding the metal wire, the metal wire running through these parts must be sealed by the molding tool. This is not possible with two webs of metal wire running side by side and thus perpendicular to the main plane of extension of the elastic bearing. If the closure can only be closed by the molding tool relatively far away from the area of the spring body which is actually to be sprayed around the metal wire, relatively large extensions of the elastomer material arise which have no function for the elastic bearing and therefore only cause additional material costs. In the embodiment initially described in this paragraph, the non-functional volume of the elastomer material can be kept very small.

The one-piece section made of the metal wire can, however, also be bent to form the holding bracket in such a way that the metal wire is juxtaposed in an upper horizontal region of the holding bracket. lying bends upwards ends freely. Apart from the area of fastening eyes, the retaining bracket can have only a single track of the metal wire everywhere. Sealing a mold for injecting the elastomer material onto the metal wire is particularly easy. The free ends of the metal wire do not result in excessive elasticity of the upper horizontal section of the holding bracket, because the distance of the free ends from the stabilized fastening eyes is typically very small. The bends also reliably prevent the spring body made of elastomer material from moving down from the metal wire in its main direction of extension. Overall, the bracket is stable and reliable with a minimal amount of material not only on the elastomer material, but also on the metal wire itself.

The spring body of the new elastic bearing preferably has spring arms directed downward and upward between the bearing bush and the retaining bracket, in the end region of which the elastomer material encloses the metal wire running horizontally there. Due to the basically low tensile load on the elastomer material on the new elastic bearing, the spring arms can be arranged in the direction essential for the vibration isolation from top to bottom without this leading to undesirable impairment of the service life of the elastic bearing. However, it is also readily possible to design the spring arms to be curved or kinked here, in order to achieve even greater security against excessive tensile stresses.

It is particularly preferred if the spring body has two spring arms directed laterally upwards from the bearing bush and / or two spring arms directed laterally downwards from the bearing bush, between which a stop buffer made of elastomer material is provided on the side of the metal wire facing the bearing bush. The stop buffer is provided for the bearing bush of the spring body. Additional stop buffers can be formed on the bearing bush itself his. With the new elastic bearing it is possible in the absence of a rubber-metal connection of the spring body made of elastomer material with the metal bracket that the spring body moves relative to the bracket. The stop buffers between the spring arms then ensure that the spring body is not deformed by this displacement.

The displaceability of the spring body made of elastomer material in relation to the retaining bracket without a rubber-metal connection can be used specifically in the new elastic bearing to compensate for horizontal displacements between the exhaust system and a vehicle floor. For this it is sufficient if the spring arms along the metal wire over a certain range, i. H. are limited, movable. However, shifting does not usually mean that a brief horizontal shift is also possible. Rather, there is usually only a slow horizontal displacement under the influence of vertical vibrations of the spring body, which reduce the effective friction between the elastomer material of the spring body and the metal wire of the bracket. However, this is completely sufficient to bridge thermal expansion of the exhaust system or any tolerances.

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

1 shows the elastic bearing in a first embodiment in a side view on its main extension plane,

FIG. 2 shows a top view of the elastic bearing according to FIG. 1,

FIG. 3 shows a view of the elastic bearing according to FIGS. 1 and 2 from the front and rear,

Figure 4 is a side view of the bracket of the elastic Bearing according to Figures 1 to 3,

FIG. 5 shows a plan view of the holding bracket according to FIG. 4,

Figure 6 is a view of the bracket according to Figures 4 and 5 from the front and rear.

Figure 7 shows the elastic bearing in a second embodiment in a side view corresponding to Figure 1 and

8 shows a plan view of the retaining bracket of the elastic bearing according to FIG. 7.

The elastic bearing 1 has a holding bracket 2 which is closed in a ring in its main extent plane and which is formed from a section 3 of a metal wire 16. A spring body 4 made of elastomer material 5 is mounted on the holding bracket 2. The spring body 4 has a bearing bush 6 for receiving a fastening element to be supported, which is formed here in one piece from the elastomer material 5. Two lower spring arms 7 and two upper spring arms 8 extend from the bearing bush 6 to the retaining bracket 3. The spring arms 7 and 8 each attach laterally to the bearing bush 6 and extend to a lower horizontal region 9 and an upper horizontal region 10 of the Holding bracket, each forming a 90 ° bend. In the end region of the spring arms 7 and 8 facing away from the bearing bush 6, the elastomer material 5 encompasses the metal wire 16 in the form of a loop 11, which at least in the basic state of the elastic bearing rests on the circumference of the metal wire 16. There is no rubber-metal connection between the two Surfaces of the elastomeric material 5 and the metal wire 16 are formed. Between the loops 11 of the lower spring arms 7 and the loops 11 of the upper spring arms 8, a stop buffer 12, which also serves as a spacer, is made of elastomer material 5. The stop buffers 12 also take into account the fact that the loops 11 are here basically the Metal wire 16 can move along in the horizontal direction. This shift should not deform the shape of the spring body 4. However, it can be used, for example, to compensate for thermal expansions of an exhaust system which is mounted on a vehicle floor with the elastic bearing 1. It can be assumed that the thermal recess of the exhaust system does not directly move the spring body 4 in the horizontal direction relative to the holding bracket 2. Rather, the displacement takes place only under the influence of vertical vibrations of the bearing bush 6 relative to the retaining bracket 2, which reduce the effective friction between the loops 11 and the metal wire 16. In their basic function, the stop buffers 12 are provided for the buffered attachment of the bearing bush 6 to the holding bracket 2. For this purpose, they extend essentially on the side of the metal wire 16 facing the bearing bush 6. A pure stop buffer 13 is formed on the upper side of the bearing bush 6. The stop buffer 13 ensures a symmetrical distribution of the vertical spring travel of the elastic bearing 1 as soon as it is loaded by the weight of the component supported by the bearing bush 6 via the fastening element to be supported. The metal wire 16 has a rounded, here circular cross section. Around this cross section, the spring body 4 can also be moved somewhat out of the main plane of extension of the bearing 1 in the lateral direction. The metal wire 16 not only forms the retaining bracket 2 but also fastening eyes 14 for fastening the elastic bearing 1, for example on a vehicle floor. The metal wire 16 extends from the fastening eyelets 14, initially forming an offset 15, into the upper horizontal region 10 of the retaining bracket 2. The offset 15 ensure that the spring body 4 does not pass through the upper horizontal region 10 of the retaining bracket 2 Function of the vehicle floor is impaired. The metal wire 16 is provided in two lanes in the upper horizontal region 10. In the lower horizontal area 9, it is single-lane. The two-lane of the metal wire 16 in the upper horizontal region 10 prepares When spraying the spring body 4 made of elastomer material in a two-part form around the bracket 2 around certain sealing problems. The two webs of metal wire 16 which run laterally next to one another cannot be sealed by the molding tool. Sealing therefore takes place in an area in which the metal wire 16 runs in one lane. That is, once in front of the fastening eyelets 14 and once at the beginning of the vertical regions of the holding bracket 2. Extensions 17 of the elastomer material extend to this point, which have no function when using the elastic bearing 1. Rather, these extensions 17 can even tear open in the event of horizontal displacements of the spring body 4 relative to the holding bracket 2, without the function of the elastic bearing 1 being impaired thereby. The metal wire 16, of which the section 3 consists, can in turn be corrosion-resistant. However, it is also possible to use a metal wire coated with a corrosion protection layer, as long as this corrosion protection layer does not lead to abrasion of the elastomer material 5 in the area of the loops 11 when the elastic bearing 1 is subjected to dynamic stress. The ends 18 at which the metal wire 16 has been cut to length for the section 3 need not themselves be provided with a corrosion protection layer if the corrosion protection layer on the remaining metal wire 16 galvanically prevents or at least limits the corrosion of the section 3 in the region of the ends 18 . The holding bracket 2 formed from the metal wire 16 is a bent wire part which can be manufactured with sufficiently high stability at comparatively low production costs. It should be taken into account that in the new elastic bearing, the holding bracket 2 is rigid in comparison to the spring body 4 made of elastomer material 3, ie it is not significantly deformed by the dynamic stresses of the elastic bearing 1.

The embodiment of the elastic bearing 1 according to FIG. 7 differs from that of FIGS. 1 to 3 initially by a different shape of the holding bracket 2. This Bracket 2 is shown separately in Figure 8. The holding bracket 2 again consists of a section 3 of metal wire 16. However, the metal wire 16 is only provided in one lane with the exception of the area of the fastening eyelets 14. That is, the metal wire 16 extends once through a horseshoe shape between the mounting lugs 14 to form the lower horizontal region 9 and the adjacent vertical regions of the bracket, and once from each mounting lug 14 it ends freely laterally around the upper horizontal region 10 of the bracket to train. In the middle of the horizontal region 10, the free ends 18 of the section 3 are bent upwards, the bends lying next to one another in the main plane of extension of the elastic bearing 1. The bends reliably prevent the loops 11 formed from the elastomeric material 5 from being pulled off the metal wire 16 on the upper spring arms. The single-lane design of the retaining bracket 2 from the metal wire 16, except for the area of the fastening eyelets 14, not only means that the material expenditure for the section 3 is minimized. It also enables the upper loops 11 to be molded on without the need for extensions 17 according to FIG. 1 must, because a mold for molding the loops 11 can not be sealed directly adjacent to the loops 11 or a spacer 12. Strictly speaking, the spacer 12 here only has the function of an upper stop for the stop buffer 13. The actual distance between the loops 11 is already defined by the free bent ends 18 of the section 3. The free ends 18 can end at the same height as the top of the fastening eyelets 14 Moving the bearing bush 6 laterally out of the main extension plane of the elastic bearing 1. In the embodiment of the elastic bearing 1 according to FIG. 7, however, the elastomer material 5 is vulcanized onto the metal wire 16 of the retaining bracket 2, so that the loops 11 at the end of the lower spring arms 7 and upper spring arms 8 basically their position in relation to the metal wire 16 maintained. The rubber-metal connection created by vu 1 ca nizing the elastomer material is supported here by the loop-shaped connection of the spring body 4 to the metal wire 16 by providing a larger contact area and by a failure of the rubber-metal connection through the loops 11 does not lead to failure of the elastic bearing 1.

B E Z U G S Z E I C H E N L I S T E

1 - elastic bearing

2 - bracket

3 - section

4 - spring body

5 - elastomer material

6 - bearing bush

7 - lower spring arm

8 - upper spring arm

9 - lower horizontal area

10 - upper horizontal area

11 - loop

12 - spacers

13 - buffer

14 - fastening eyelet

15 - bend

16 - metal wire

17 - continuation

18 - end

Claims

PATENT REPRESENTATION

1. Elastic bearing, in particular for suspending an exhaust system on a vehicle floor, with an annular retaining bracket, with fastening eyelets for the fixed attachment of the retaining bracket and with a spring body made of elastomer material, which is mounted on the retaining bracket and which has a bearing sleeve for a support bracket within the retaining bracket Fastening element is supported elastically, characterized in that the holding bracket (2) is formed from a one-piece section (3) of a metal wire (16), which also forms the fastening eyes (14) for the fixed attachment of the holding bracket (2).

2. Elastic bearing according to claim 1, characterized in that the holding bracket (2) made of metal wire (16) is formed with a rounded cross section.

3. Elastic bearing according to claim 1 or 2, characterized in that the elastomer material (5) encloses the metal wire (16) with or without the formation of a rubber-metal connection.

4. Elastic bearing according to one of claims 1 to 3, characterized in that the metal wire (16) is rustproof or protected against corrosion.

5. Elastic bearing according to one of claims 1 to 4, characterized in that the metal wire (16) is a spring steel wire, the stiffness of the bracket (2) compared to the stiffness of the spring body (4) made of the elastomer material (5) so is large that it does not deform significantly during normal operation of the elastic bearing (1).

6. Elastic bearing according to one of claims 1 to 5, characterized in that the fastening eyes (14) relative to the upper horizontal region (10) of the bracket (2) are bent upwards.

7. Elastic bearing according to one of claims 1 to 6, characterized in that the metal wire (16) in its course direction only in the area of the fastening eyes (14) has two tracks next to each other.

8. Elastic bearing according to claim 7, characterized in that the metal wire (16) in an upper horizontal region (10) of the bracket (2) with adjacent bends ends freely upwards.

9. Elastic bearing according to one of claims 1 to 8, characterized in that the spring body (2) between the bearing bush (6) and the retaining bracket (2) downward and upward spring arms (7 and 8), in the end region of which Elastomeric material (5) encloses the metal wire (16) running horizontally there.

10. Elastic bearing according to claim 9, characterized in that the spring body (2) two spring arms (8) laterally directed upwards from the bearing bush (6) and / or two spring arms (7) directed laterally downwards from the bearing bush (6) has, between which on the bearing bush (6) facing side of the metal wire (16) a stop buffer (12) made of elastomer material (5) is provided.