GB2253259A

GB2253259A - Vibration-damping bearing for an internal combustion engine

Info

Publication number: GB2253259A
Application number: GB9203008A
Authority: GB
Inventors: Mario Caramagna
Original assignee: IAO Industrie Riunite SpA
Current assignee: IAO Industrie Riunite SpA
Priority date: 1991-02-13
Filing date: 1992-02-13
Publication date: 1992-09-02
Also published as: GB9203008D0; ES1020192Y; DE9201837U1; IT221621Z2; ITMI910113U1; ITMI910113V0; ES1020192U

Abstract

The vibration-damping bearing comprises an outer component 2 which may be fastened on the chassis of the motor vehicle and an inner component 4 which may be fixed on the engine, having an elastic element 8 provided between the inner component and the outer component, with parts 6, 7 of the outer component 2 and the inner component 4 respectively being non-linear in cross-section, for example arcuate or V-shaped, in the direction F of transverse force. <IMAGE>

Description

VIBRATION-DAMPING BEARING FOR AN INTERNAL COMBUSTION ENGINE The present invention relates to a vibration-damping bearing for an internal combustion engine. In particular to bearings having an outer part fastenable on the chassis of a vehicle and an inner part fixable to the vehicle engine, with an elastic portion between the inner and outer parts.

A bearing is described, for example, in Italian Utility Model 194,706 to which reference is made as prior art.

Vibration-damping bearings are used to support internal combustion engines on the chassis of motor vehicles especially in the case of heavy vehicles, for example, lorries. Such bearings are used to absorb forces caused by shocks to which the vehicle is exposed, lateral accelerations when cornering and forces which arise from the driving torque of the engine, so as to minimise undesirable oscillatory movements of the engine in the three main directions between engine and vehicle chassis, i.e. in a vertical, longitudinal and transverse direction.

Undesirable movements in a vertical direction are restricted by the use of horizontally disposed damping elements, which are arranged between an inner component and an outer component of the bearing. Transverse movements of the bearing are restricted by a damping element which is disposed on the outside of the inner bearing body. However, bearings according to the prior art are not effective enough, and lateral vibrations do occur resulting in undesirable contact between the vehicle chassis and the bearing. Such contact is undesirable mechanically, is extremely noisy and adversely affects the comfort of the driver of the vehicle.

A reaction to the driving torque of the engine also causes vibrations and shaking movements in a longitudinal direction of the engine. These movements cause driver discomfort and rapid wear of the power transmission components of the engine.

In order to decrease the vibrations it is desirable to increase the transverse rigidity of the bearing. The thickness of the vibration dampers, the elastic elements between the lateral components of the bearing could be reduced or the width of the elastic elements could be increased. In both cases, however, it has been found, that, for only a slight increase in the transverse rigidity of the apparatus, there is a sharp increase in rigidity in a vertical and longitudinal direction. This leads to an unacceptable reduction in the damping of vibrations produced when the engine is running.

The present invention provides a bearing avoiding some of the drawbacks of the prior art and makes it possible to improve the transverse rigidity of the elastic components without increasing the rigidity in a vertical and longitudinal direction of the bearing. This substantially reduces knocking of the outer bearing parts against the vehicle chassis, improving driver comfort and extending the service life of the drive parts of the vehicle.

According to the present invention there is provided a vibration-damping bearing for internal combustion engines, comprising an outer component to be fastened to the chassis of the vehicle and an inner component to be fixed to the engine, having an elastic element provided between the inner component and the outer component, wherein at least one of the components has a non-linear cross-section.

Preferably at least one of the components, advantageously both, has two parts extending in directions which are inclined to each other by a finite angle, which may be between 40 and 20 .

According to one embodiment this may be achieved by components with an arcuate, or alternatively a V-shaped cross section.

Preferably a bisector of the V-shape components is disposed substantially perpendicular to the direction of the transverse force which acts upon the vibration-damping bearing.

In a preferred embodiment the angle of inclination of the lateral components of the V-shaped body is between 40 and 200 relative to the plane of the transverse force line.

One advantage of a damping bearing according to the invention is that, in the event of transverse movements, the energy produced is substantially absorbed by the elastic component of the bearing and is generally not dissipated, for example, by repeated knocking of outer-lying damping elements against the vehicle chassis.

A further advantage of a bearing according to the invention is that the inclined arrangement of the lateral parts of the bearing makes it possible to alter the transverse rigidity of the damping means while the rigidity in a vertical and longitudinal direction may be reduced and yet the overall dimensions of the damping bearing remain unaltered. A further advantage of the damping means according to the invention is that the available surface area for adhering the elastic component to the lateral parts of the bearing is increased, thereby creating an improved adhesive join.

The invention will now be described, by way of example, with the help of the accompanying drawings, in which: Fig. 1 is a front view of a known vibration damper; Fig. 2 is a sectional view along the line II-II of the apparatus of Fig. 1; Fig. 3 is a sectional view of a vibration-damping bearing constructed according to the invention; and Fig. 4 is a sectional view showing a vibrationdamping bearing according to the invention in its position as a result of transverse loading.

The vibration damper 1 shown in Figs. 1 and 2 corresponds to a vibration damper according to Italian Utility Model 194,706, a prior publication representing prior art.

The known bearing 1 comprised an open body 2, which has bearing lugs 3 for fastening the vibration damper to a vehicle chassis (not shown). A cup-shaped body 4 is fitted with a bearing lug 5 to allow it to be fastened with screws to the engine (not shown). Between the two parts 6 of the body 2 and the lateral parts 7 of the inner part 4, an insert 8 is fastened. The insert 8 is made of an elastic material and is fastened in a known way e.g. by a vulcanising process. In the illustrated example, the two components 8 are connected to one another by an upper pillow 9 and a lower pillow 10, which are disposed with play between the upper components 11 and 12 and the lower components 13 and 15 of the outer body 2 and the inner body 4. There is an outer elastic insert fastened to the bottom of the inner body 4 which has not been shown in the drawing.

In this known construction, the lateral parts 6 and 7 of the outer body 2 and the inner body 4 are straight flat parts in cross-section as shown in Fig. 2.

In the known construction, of Figs 1 and 2, the transverse forces (F) cause deformation of the elastic insert 8, in the manner indicated in Fig. 2 by the dash-dot lines. This results in undesirable cutting forces extending parallel to the linear extension of the two lateral parts 6 and 7 acting on individual material fibres of the elastic insert 8. In this construction there is reduced transverse rigidity in the elastic damping bearing.

In an embodiment according to the invention, the lateral parts 6, 7 of the outer component 2 and the inner component 4 of the new bearing 1 are constructed in such a way that they are V-shaped in cross-section, as shown in Figs. 3 and 4.

The operation of a bearing according to the invention, particularly under transverse loading, will now be described with references to Figs. 3 and 4.

A transverse load F acting upon the lateral parts 6, 7 of the bearing is split by the two arms of each V-shaped component 8, as shown in Fig. 4 into two components: a cutting force component t parallel to the surfaces, directed towards one another, of the lateral components 6, 7, and a compressive or tensile component 6 extending at right angles to the surfaces.

For component 6, the desired increase in the transverse rigidity of the bearing 1 is achieved without altering the rigidity predominant in a vertical direction.

The value of the component for force 6 is variable by altering the angle a of inclination of the lateral components 6, 7.

In practice, splitting of the force F into components 6 and r may alternatively be effected by making the lateral components 6 and 7 arc-shaped.

Practical experiments have shown that the ratio between rigidity in a longitudinal direction and rigidity in a vertical direction of the bearing is approximately 2 for bearings having the features of Italian Utility Model 194,606.

In a bearing with features according to the present invention and an angle of inclination a of 150, a ratio of approximately 3 is achieved between longitudinal rigidity and rigidity in a vertical direction.

The ratio between transverse rigidity and rigidity in a vertical direction is approximately 0.4 in bearings according to Italian Utility Model 194,706 and around 1 in bearings according to the invention using an angle of inclination a of 150.

The components 6 and 7 are arranged and constructed so that a line X bisecting them is generally perpendicular to the direction of the force F.

Claims

1. A vibration-damping bearing for internal combustion engines, comprising an outer component to be fastened to the chassis of the vehicle and an inner component to be fixed to the engine, having an elastic element provided between the inner component and the outer component, wherein at least one of the components has a nonlinear cross-section.

2. A bearing according to claim I wherein at least one of the components has two parts extending in directions which are inclined at one angle to each other.

3. A bearing according to claim 2 wherein the angle of inclination is between 40 and 20 .

4. A bearing according to claim 2 or claim 3 wherein one of the parts extends in a direction which makes an angle of between 40 and 200 to the direction of the transverse force which will act on the elastic element in use.

5. A bearing according to claim 4 wherein said part is laterally positioned relative to the other part.

6. A bearing according to any one of the preceding claims wherein at least one of the components has an arcuate cross-section.

7. A bearing according to any one of the preceding claims wherein at least one of the components has a substantially V-shaped cross-section.

8. A bearing according to any preceding claim, wherein the inner and outer components are arranged and constructed so that a line bisecting the components is generally perpendicular to the direction of the transverse force which will act upon the elastic element in use.

9. A bearing substantially as hereinbefore described with reference to Fig. 3 or Fig. 4.