Elastic loop for suspending the exhaust system of a motor vehicle

An elastic loop 1 is provided for suspending an exhaust system of a motor vehicle at a vehicle floor of the motor vehicle. The elastic loop 1 has a basic body 4 made of an elastomeric material 5, the basic body 4 enclosing two receiving eyes 6 and 7, one of which being provided for receiving a supporting part, and the other of which being provided for receiving a part to be supported, and the basic body 4 comprising at least two elastic supporting bands 8 and 9 which run from the one receiving eye 6 to the other receiving eye 7 in a main plane of extension and operation of the loop. Further, the elastic loop 1 has a ring 21 enclosing the basic body 4 in the main plane, the ring 21 being a pre-cut piece 24 of a ribbon 20 which is continuously woven in consecutive one-layer and two-layer areas, i.e. once in a single closed layer and once in two separate layers, the pre-cut piece 24 including an entire two-layer area and at least parts of both adjacent one-layer areas.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to co-pending German Utility Model Application No. DE 20 2005 008 665.7 entitled “Elastische Schlaufe, insbesondere zur Aufhängung der Abgasanlage eines Kraftfahrzeugs” (Elastic loop for suspending the exhaust system of a motor vehicle), filed Jun. 3, 2005.

FIELD OF THE INVENTION

The present invention relates to an elastic loop for suspending an exhaust system of a motor vehicle at a vehicle floor of the motor vehicle, the elastic loop having a basic body made of an elastomeric material, the basic body enclosing two receiving eyes, one of which being provided for receiving a supporting part, and the other of which being provided for receiving a part to be supported, and the basic body comprising at least two elastic supporting bands which run from the one receiving eye to the other receiving eye in a main plane of extension and operation of the loop, and a ring made of a tear-resistant ribbon enclosing the basic body in the main plane and serving as a loss safety.

PRIOR ART

An elastic loop for suspending an exhaust system of a motor vehicle at a vehicle floor of the motor vehicle is known from German Utility Model DE 295 06 970 U1. Besides two supporting bands running in a main plane of extension and operation of the loop from one receiving eye to the other, this loop has a loss safety as a further connection of the receiving eyes, which is a closed ring made of a tear-resistant ribbon. This loss safety encloses the basic body made of elastomeric material, which forms the receiving eyes and the supporting bands. The inner circumference of the loss safety is bigger than the outer circumference of the basic body in the unloaded state of the elastic loop. Thus, the known elastic loop has a two stage spring characteristic, the first stage of which ends, when the basic body is loaded to such an extent that its outer circumference is as big as the inner circumference of the loss safety so that the loss safety abuts against the outer circumference of the basic body. In this way, the elastic loop can be kept comparatively soft without affecting the safety in suspending an exhaust system of a motor vehicle at the vehicle floor.

In the actual embodiment of the elastic loop known from DE 295 06 970 U1 the ends of a pre-cut piece of the tear-resistant ribbon are sewn together to make the closed ring of the tear-resistant ribbon for the loss safety.

Both published German Patent Application DE 26 58 358 A1 and German Patent DE 199 06 548 C1 disclose elastic loops having a loss safety integrated in the basic body. This construction increases the production cost and does not allow for easily obtaining a two stage spring characteristic.

All parts of a motor vehicle are subject to a high cost pressure. The intension is to reduce the production cost of the parts and thus their contribution to the total cost of the motor vehicle as far as possible but without loosing performance of the parts.

Thus there is a need for an elastic loop for suspending the exhaust system of a motor vehicle at a vehicle floor of the motor vehicle, which can be produced at reduced cost without loosing performance.

SUMMARY OF THE INVENTION

In one aspect, the invention provides an elastic loop for suspending an exhaust system of a motor vehicle at a vehicle floor of the motor vehicle, the elastic loop having a basic body made of an elastomeric material, the basic body enclosing two receiving eyes, one of which being provided for receiving a supporting part, and the other of which being provided for receiving a part to be supported, and the basic body comprising at least two elastic supporting bands which run from the one receiving eye to the other receiving eye in a main plane of extension and operation of the loop, and a ring enclosing the basic body in the main plane, the ring being a pre-cut piece of a ribbon which is continuously woven in consecutive one-layer and two-layer areas, i.e. once in a single closed layer and once in two separate layers, the pre-cut piece including an entire two-layer area and at least parts of both adjacent one-layer areas.

Further, in a more detailed aspect, the invention provides an elastic loop for suspending an exhaust system of a motor vehicle at a vehicle floor of the motor vehicle, the elastic loop having a basic body made of an elastomeric material, the basic body enclosing two receiving eyes, one of which being provided for receiving a supporting part, and the other of which being provided for receiving a part to be supported, and the basic body having two outer supporting bands and two inner supporting bands which all run in a main plane of extension and operation of the loop from the one receiving eye to the other receiving eye, and a ring enclosing the basic body in the main plane, the ring being a pre-cut piece of a ribbon which is continuously woven in consecutive one-layer and two-layer areas, i.e. once in a single closed layer and once in two separate layers, the pre-cut piece including an entire two-layer area and at least parts of both adjacent one-layer areas, the ring having an inner circumference which is bigger than an outer circumference of the unloaded basic body, and the ring being held on the main body by protrusions which protrude from the basic body once on the one side of the ring and once on the other side of the ring at the outer circumference of the basic body.

In the new elastic loop the ring extending around the basic body of elastomeric material is a pre-cut piece of a ribbon which has been continuously woven in consecutive one-layer and two-layer areas, i.e. once in a single closed layer and once in two separate layers. The pre-cut piece of the ribbon includes a full two-layer area and at least parts of both adjacent one-layer areas. Thus, the circumference of the ring is defined by the lengths of the two layers of the two-layer area, each layer defining a half of the circumference, and the layers being held together by the adjacent one-layer areas. The two parts of the two adjacent one-layer areas may be provided at the inner or at the outer circumference of the ring and may protrude from it.

A ribbon having consecutive one-layer and two-layer areas can be produced by weaving techniques which are known as such. At least, with regard to its dimensions required here, such a ribbon is used in the technical field of motor vehicles for the first time. The dimensions relevant here typically range from 50 to 150 mm with regard to the length of the two-layer area corresponding to a circumference of the ring formed by this area from 100 to 300 mm; and the width of the ribbon usually is about 10 mm, i.e. typically at least 5 mm and 20 mm at maximum. Thus, as compared to the length of the two-layer area, the ribbon is comparatively narrow. So far as pre-cut pieces of ribbons with consecutive one-layer and two-layer areas have been used in the technical field of motor vehicles up to now, they have been used as connection means in which the width of the ribbon had the same order as the length of the two-layer area or in which the ribbon is even broader. I.e. even the width of the one-layer areas is much bigger in the prior art than here with the invention. Surprisingly, it has been found, that even with comparatively narrow ribbons, comparatively short parts of the adjacent one-layer areas of the ribbon are sufficient to tear-resistantly connect the two layers of the two-layer area of the band arranged in-between. This even applies with dynamic loads, as they typically occur in the use of the new elastic loop. Actually, a few millimeters of the one-layer areas at both ends of the pre-cut piece of the ribbon are sufficient for connecting the two layers of the two-layer area in a long lasting way so that the ring around the basic body remains closed even under high load. A typical length of the parts of both adjacent one-layer areas included in the pre-cut piece of the ribbon is about 5 mm, i.e. between 3 and 8 mm. Longer one-layer parts at both sides of the two-layer area are possible; however, they only increase the costs of the ribbon. The low costs are the particular advantage of the new elastic loop, as they are considerably lower as with a ribbon, the ends of which are sewn together. The loss safety of the new elastic loop is completely manufactured by wowing the ribbon and afterwards dividing up the woven ribbon in separate pre-cut pieces.

Polyester threads are a suitable material for making the ribbon. If these threads are cut hot in dividing up the ribbon into the pre-cut pieces, the threads at the cut edges melt together, and thus any dissolution of the woven structure of the ribbon starting at its cut edges is inhibited. However, with tightly woven ribbons this danger of dissolution of the woven structure is only small, if existing at all.

If the ring of the new elastic loop has an inner circumference which is bigger than the outer circumference of the unloaded basic body, the ring results in a two stage course of the spring characteristic of the elastic loop displaying a progressive slope as soon as the outer circumference of the basic body abuts against the inner circumference of the loss safety under load.

As long as the ring is still loosely arranged on the basic body, it can be held by protrusions of the basic body in a defined position with regard to the basic body. It is particularly preferred, if these protrusions are intermittingly provided on both sides of the loss safety at the outer circumference of the basic body.

In the new elastic loop, the basic body may have two inner supporting bands in addition to two outer supporting bands, which, like the outer supporting bands, run in the main plane of extension and operation of the loop between the receiving eyes. By these additional inner supporting bands an increased lateral stability normal to the plane of main extension is achieved, as compared to simple elastic loops having only one pair of supporting bands and similar spring properties within the main plane of the loop. This is due to the fact that the connection points of the inner supporting band to the receiving eyes are automatically closer together than the connection points of the outer supporting bands.

In this regard it is particularly preferred, if, within the main plane of the loop, a distance of each connection point of each inner supporting band to each receiving eye is smaller than any distance of any connection point of any outer supporting band to the same receiving eye.

With a similar course and with an at least not much stronger curvature or bending of the inner supporting bands, the construction defined above means that the inner supporting bands are shorter than the outer supporting bands.

If the inner supporting bands have a smaller effective cross section normal to the main plane of the loop than the outer supporting bands, the supporting bands have a particular small influence on the spring properties of the elastic loop within its main plane. However, even with such comparatively thin inner supporting bands, a considerable increase in lateral stability of the new elastic loop is achieved. In this context, the term effective cross section refers to the cross section of the supporting bands which provides for the formation of counter-forces to pulling loads applied to the supporting bands.

Preferably each of the inner supporting bands of the elastic loop approximately runs in parallel to one of the outer supporting bands. For example, the supporting bands may have a slight curvature in the unloaded state of the new elastic loop and may be pulled straight by the base load on the elastic loop. In this sense, it is preferred, if the inner supporting bands as well as the outer supporting bands have a straight shape.

In the sense of the present invention, the inner supporting bands are tuned to the outer supporting bands in an optimum way, if the inner supporting bands provide a smaller-counter force upon changes of the distance of the receiving eyes in the main plane of the loop than the outer supporting bands, but provide a higher counter-force upon movements of the receiving eyes normal to the main plane of the loop than the outer supporting bands.

In the new elastic loop, each receiving eye is to be formed in such a way that it receives a bolt of circular cross-section, for example, without any tilting play with regard to the main plane of the loop. Only if the receiving eyes receive the respective supporting part and the part to be supported without play, the high lateral stability of the new elastic loop can be exploited.

Suitable receiving eyes of the new elastic loop may have a circular or star-shaped free cross sectional area, for example. The star-shaped cross section may make it easier to introduce balls having extended heads at their tips or showing tolerances in diameter.

It is particularly preferred in the new elastic loop, if each of the receiving eyes is directly formed by the basic body of elastomeric material so that no additional materials are used beside the elastomeric material.

The basic body of the new elastic loop as such includes no reinforcing layer. This allows for making the supporting bands as simple pulling bands for tensional stress only. At the same time, doing without any reinforcement is a considerable cost advantage.

DETAILED DESCRIPTION

Referring now in greater detail to the drawings,FIG. 1illustrates an elastic loop1which consists of a loss safety3represented with a dashed line2and a single basic body4of elastomeric material5. The basic body4displays the following details: two receiving eyes6and7, two outer supporting bands8, two inner supporting bands9, stops10and11, and protrusions12and13at its outer circumference. The receiving eyes6and7are arranged in parallel to each other and normal to the main plane of extension and intended operation of the elastic loop1, which corresponds to the drawing plane, when swiveling axes16and17are considered which are defined by the receiving eyes6and7. In operation, the elastic loop1may swivel about the swiveling axes16and17with regard to connection elements engaging the receiving eyes6and7. The receiving eyes6and7are each provided for receiving a bolt of circular cross-section; the receiving eye6receives a bolt of a supporting part and the receiving eye7receives a bolt of a part to be supported. The supporting bands8and9connect the areas of the basic body4forming the receiving eyes6and7. They serve for supporting loads acting between the receiving eyes6and7. The supporting bands8are outer supporting bands, which are directly adjacent to the outer circumference15of the basic body5. Like the outer supporting bands8, the inner supporting bands9run from the receiving eye6to the receiving eye7in the main plane of the elastic loop1. Each inner supporting band9has about the same curvature as its neighboring outer supporting band8, i.e. it runs about in parallel to this outer supporting band8. The slight curvatures of the supporting bands8and9in the unloaded state of the elastic loop1depicted inFIG. 1, however, mainly get lost, when the elastic loop1is built-in for suspending an exhaust system of a motor vehicle at a vehicle floor of the motor vehicle, and is thus subjected to a base load. Then, all supporting bands8and9are about straight and run in parallel to each other because of the base load. Within the plane of main extension of the elastic loop1, connection points18of the outer supporting bands8to the receiving eyes6and7are both in the direction of the distance of the receiving eyes6and7and normal thereto farther away from the receiving eyes6and7than connection points19of the supporting bands9. Correspondingly, the supporting bands8are clearly longer than the supporting bands9. On the other hand, the supporting bands8have twice the cross section of the supporting bands9, the cross sections being mainly constant over the entire lengths of the supporting bands. In total, the thinner inner supporting bands9have a smaller effect on the spring stiffness of the elastic loop1between the receiving eyes6and7than the thicker outer supporting bands8. The lateral stability of the elastic loop1, however, which is displayed as a stiffness between the receiving eyes6and7in a direction normal to the plane of main extension of the elastic loop1, is relevantly increased by the supporting bands9. This stiffness can indeed be mainly due to the supporting bands9. The loss safety3made of a tear-resistant ribbon20extends around the outer circumference15of the basic body4as a closed ring21, and has a bigger inner circumference22than the outer circumference15, in the depicted unloaded state of the elastic loop1. Upon loading the elastic loop1by increasing the distance of the receiving eyes7, the outer supporting arms8are extended. Thus, the outer circumference15is increased until it is as big as the inner circumference22of the loss safety3. Then, a further increase of the distance of the receiving eyes6and7is only possible under extension of the loss safety3which, however, is stiff in this direction, or under deformation of the basic body4in the area between the receiving eyes6and7and the loss safety3. This results into a progressive increase of the spring characteristic of the elastic loop1. The protrusions1to14, which are protruding from the outer circumference15of the basic body4once on the one side and once on the other side of the loss safety3hold the loss safety3in its place around the outer circumference15. Here, areas23and24of the protrusions12and14extending over the loss safety3care for the loss safety3not falling off the basic body4even in the unloaded state of the elastic loop1. The stops10and11delimit a movement of the receiving eyes6and7towards each other which may occur under dynamic load. The stops10and11made of elastomeric material5care for braking down this movement of the receiving eyes6and7in a controlled way. In the manufacture of the new elastic loop1, the basic body4is made in one step of the elastomeric material5injected into a mould. Afterwards, only the loss safety3which is closed like a ring is arranged on the outer circumference15of the basic body4.

InFIGS. 2 and 3the ring21of the loss safety3accordingFIG. 1is separately depicted in two views. Actually, the ring21is a pre-cut piece24of a tear-resistant band20, which is woven in consecutive one-layer areas25and two-layer areas26, i.e. once in a single closed layer28and once in two separate layers29running in parallel to each other. The pre-cut piece24includes an entire area26and parts of the adjacent areas25. Actually, a half area25can be provided on each side of the area26in the pre-cut piece24. To this end, the tear-resistant band, which has been woven of polyester threads4, can be hot-cut into single pre-cut pieces24so that the cut edges30are sealed by melting the single threads together. By means of the parts of the areas25at both ends of the pre-cut piece24the layers29are connected to each other in a long lasting way. This connection does not get lost even under high dynamic loads onto the elastic loop according toFIG. 1. In the present embodiment the length L of the area26is 100 mm, which corresponds to an inner circumference of the ring21of 200 mm. The parts of the areas25on both sides of the area26in the pre-cut piece24are each 5 mm long. The width B of the ribbon20is 10 mm.

In principle, these figures also apply to the ring21depicted inFIG. 4. This ring21differs from the ring21shown inFIGS. 2 and 3only in that the layers29of the area26are turned inside-out so that the parts of the areas25are now pointing inwards, i.e. protrude from the inner circumference of the ring21, whereas they protrude from the outer circumference of the ring21according toFIGS. 2 and 3. This, however, does not affect the general function of the ring21in the elastic loop1according toFIG. 1. Provided with the ring21according toFIG. 4, however, the new elastic loop1has a more conventional appearance.

It is also considered to use the parts of the areas25at the ends27of the pre-cut pieces24for securing the ring21, i.e. the loss safety3, to the basic body4.

FIG. 5shows a further embodiment example of the new elastic loop1. Here, the supporting bands8and9have a stronger curvature than in the first embodiment according toFIG. 1. Additionally, the whole elastic loop has a more rhombus-shaped circumference, as the curvature of the outer supporting bands8is concentrated to their middle region. This allows for covering a greater increase of the distance between the swiveling axes16and17by a deformation instead of an elongation of the supporting bands8. As in the first embodiment according toFIG. 1, the inner supporting bands9of the elastic loop1according toFIG. 5predominantly increase the lateral stability of the elastic loop1and only have a very little influence on its spring characteristic with regard to the distance between the swiveling axes16and17. Here, however, their connection points19to the receiving eyes6and7are further away from the receiving eyes6and7than the connection points18of the outer supporting bands, but the two connection points19at the ends of each inner supporting band9are much closer together in the direction of the distance of the swiveling axes16and17than the two connection points18of each the outer supporting band8. The ring21of the elastic loop1is in the same embodiment as the ring21of previousFIGS. 1 to 3.

The embodiment example of the elastic loop depicted inFIG. 6differs from the previous embodiments in that the inner supporting bands9have a much stronger cross section than the outer supporting bands. Thus, they are providing the main component of the spring characteristic of the elastic loop1with regard to the distance between the swiveling axes16and17. Further, these inner supporting bands9do only show a very little curvature considering their extension between the swiveling axes16and17. They have nearly no curvature between their connection points19to the receiving eyes6and7. Vice versa, the outer supporting bands8are here mainly provided for increasing the lateral stability of the elastic loop1. Further, the outer supporting bands9of smaller cross section have the effect, that the second stage of the spring characteristic of the elastic loop1starting upon the outer circumference15of the basic body4equaling the inner circumference of the21has a smaller slope. This is due to the smaller deformation resistance of the thinner outer supporting bands9. Because of the stronger and nearly straight inner supporting bands9no stops10and11are necessary in the embodiment of the elastic loop1according toFIG. 6.

LIST OF REFERENCE NUMERALS