DE2716994C2 - Truck with rigid but torsionally flexible chassis frame and torsionally rigid body - Google Patents

Description

The invention relates to a truck with a rigid but torsionally flexible chassis frame according to the preamble of claim 1.

Such trucks must be able to overcome significant uneven ground without the structure becoming distorted. These requirements apply not only to paved terrain, but also to unpaved terrain, whether for civil or military purposes.

It is known that torsion-resistant bodies such as flatbeds, box bodies or tank bodies can be mounted on the torsion-flexible chassis frame of trucks in such a way that they impede the torsion as little as possible. This is the case with a three-point bearing, in which one bearing point is arranged in the middle and two other bearing points on either side (DE-Buch Bussien, Automobiltechnisches Handbuch, Volume 2, 1965, p. 809). The central bearing is rotatable via a bolt arranged lengthwise, which is attached to the chassis frame in a bracket, while rubber-metal elements are arranged for the two side attachments between the chassis frame and the body.

On the one hand, truck manufacturers have started to make the chassis frame more and more torsionally flexible in order to increase the off-road capability of the vehicle. On the other hand, bodies are increasingly being used whose torsional rigidity must be maintained. This has led to torsionally rigid bodies limiting the torsion of the chassis frame and then possibly becoming distorted themselves. The result is, for example, damage to the body or breakage of the bolt bearings, even if these are given more play by adding rubber elements. The side fastenings using rubber-metal elements cannot withstand all stresses, as the rubber part is destroyed by the effects of oil or extreme cold.

It is also known to fasten the torsion-resistant chassis frame of a trailer to a tubular longitudinal center beam in a torsion-resistant manner and to pivotally mount the rigid front and rear axles on the longitudinal center beam via tubular sleeves (DE-PS 6 75 531). The two tubular sleeves are connected to one another in an articulated manner via a compensating lever attached to the longitudinal center beam so that the torsion-resistant chassis frame is always held in the middle position between the two axles.

This proposal therefore concerns the pivoting bearing of the rigid axles of a trailer with a torsion-resistant chassis. It is not applicable to a truck of the type mentioned at the beginning with a torsion-flexible vehicle frame and a torsion-resistant body, since the truck according to the invention - specified as standard by the vehicle manufacturer to the body manufacturer - is equipped with different axle bearings compared to this proposal. In any case, a compensating lever connected in an articulated manner with two tubular sleeves would not allow the asymmetrical torsions that actually occur and would therefore impair the asymmetrical torsionability of the vehicle frame and could itself break.

The invention is based on the object of increasing the structural strength and service life of the fastening of the torsion-resistant structure to the torsion-flexible chassis frame in trucks of the type mentioned at the outset and at the same time improving the torsionability of the chassis frame.

This object is achieved in a generic truck by the characterizing features of claim 1. The invention results in the advantages, for example, that the construction is significantly lighter and therefore less expensive and that the construction of the lateral fastening points can also be kept simpler. There, the sliding plates can perform longitudinal movements with regard to the play between them and the anchor, but can also tilt against each other due to the springy flexibility of the anchor in the longitudinal direction. Above all, however, the new bearing of the central tube reduces the material stresses in both parts when the chassis frame is twisted. The service life is increased on the one hand due to the low specific surface pressure and on the other hand due to the simple bearings and the low stresses on the structure, or the structure is correspondingly lighter. It has also been shown that there is no susceptibility to failure and the service life is long.

The construction can be simplified even further if the bearing shells are designed as pans and the central tube is resiliently clamped against them by means of hold-down devices such as clamps.

The safety measures to prevent longitudinal displacement of the central tube relative to the Chassis frames, which were also required in the previously known designs, can now be arranged in a very simple manner directly on the central tube and can be provided as stops between the central tube and the bearing shells, whereby it is still sufficient to provide only two stops opposite one of the two bearing shells.

The invention is explained using an embodiment shown in the drawing. Here, in offset planes,

Fig. 1a and 1b each show a cross section through a central and a lateral fastening point and

Fig. 2a and 2b each show a longitudinal section through a central fastening point and a lateral fastening point according to Fig. 1a and 1b respectively.

A bearing shell 6 is welded to the chassis frame 5 at 7 and is equipped with a wear plate 8. This forms the actual bearing for a central tube 9 and surrounds it on part of the circumference, whereby this bearing point is only shown in the left half of the drawing in Fig. 1a. The central tube 9 is pressed against the bearing shell 6 and the wear plate 8 via a clamp 10 , whereby the clamp 10 is clamped via nuts 11 with clamping elements 12 inserted between them. A further wear plate 13 is inserted between the clamp 10 and the central tube 9 .

In the middle length of the central tube 9 , cross struts 14 with stiffeners 15 are welded to both sides of the tube (shown in Fig. 2b), the ends of which - not shown in Fig. 1b - are shown in cross section. As can be seen from this, the ends of the cross struts 14 are equipped with sliding plates 16 , while corresponding sliding plates 16 ' are screwed to the chassis frame 17 .

The sliding plates 16 ' are relatively short so that any tilting that occurs has no effect. The structure is clamped down onto the chassis frame 17 via spring-loaded anchors 19. The sliding plates 16 and 16 ' are made of a wear-resistant material, and the relative play between them occurs when the chassis frame is twisted.

Claims (6)

1. A truck with a rigid but torsionally flexible chassis frame which is connected to a torsionally rigid superstructure via three-point bearings with central and lateral fastening points, characterized in that the superstructure has a central tube ( 9 ) which is movable about a horizontal axis and which is centrally mounted at both ends on the chassis frame ( 5 ) in bearing shells ( 6 ), while at the lateral fastening points both on the chassis frame ( 17 ) and on the superstructure and between them sliding plates ( 16 , 16 ') are horizontally fastened, which can be braced against one another with play by an anchor ( 19 ) each subject to longitudinal spring force. 2. A truck according to claim 1, characterized by bearing shells ( 6 ) designed as pans and the central tube ( 9 ) resiliently clamped against these by hold-down devices, such as clamps ( 10 ). 3. A truck according to claim 1 or 2, characterized by longitudinal thrust protection devices such as stops ( 24 ) arranged on the central tube ( 9 ). 4. A truck according to claim 3, characterized by stops ( 24 ) arranged on the central tube ( 9 ) opposite one of the two bearing shells ( 6 ). 5. A truck according to one of claims 1 to 4, characterized by the arrangement of wear plates ( 8 , 13 ) between bearing shells ( 6 ) and central tube ( 9 ) or hold-down devices ( 10 ) and central tube ( 9 ). 6. A truck according to one of claims 2 to 5, characterized by the use of clamping elements ( 12 ) on the hold-down devices ( 10 ).