Compactors according to the invention are used to effectively compact materials and to crush material. Due to this, the compactors are heavy and have cylindrical rollers as wheels. On account of the large masses and slow driving speed, hydrostatic transmissions are preferably used in the compactors. Usually, the compactor's diesel engine is used to rotate one or more hydraulic pumps. The hydraulic pumps are used in turn-co rotate hydraulic motor units arranged to rotate the rollers. Normally, there is at least one hydraulic motor unit in connection with each roller.

In compactors, the roller is support rotatably by means of bearing assemblies in the end-pieces of the roller frame. In small and narrow compactors, it is relatively easy to locate the hydraulic motor unit directly in the end of the roller, as disclosed in US 4,089,616, for example. Often, only a low-speed hydraulic motor is used as the hydraulic motor unit in small compactors. In larger compactors, the power required is considerable, so that, in addition to the hydraulic motors, some form of gearbox is required. By locating the hydraulic motor, the gearbox, and the bearing assembly in the end of the roller, the compactor's transmission arrangement becomes complicated and expensive. At the same time, the transmission

arrangement requires a great deal of space for installation. In addition, in large compactors, it is difficult to align a hub motor, which is as such known, with the axis of rotation of the roller. Thus, in large rollers, the chain-drive arrangement according to publication US 4,854,772 is generally used.

The invention is intended to create a compactor transmission arrangement, which is simpler than previous arrangements and in which ready-made components can be utilized. The characteristic features of the present invention appear in the accompanying Claims. A roller transmission arrangement according to the invention is arranged centrally on the axis of rotation of the roller. This also protects the transmission arrangement, which is preferably assembled from standard components, inside the roller. In addition, the roller is supported in such a way that bearings that specifically support the roller are not required in the compactor, which further simplifies the construction of the compactor's transmission arrangement. The transmission arrangement also does not limit the maximum width of the compactor.

In the following, the invention is explained in detail, with reference to the accompanying drawings, depicting one embodiment of the invention, in which Figure la shows a side view of a compactor equipped with a transmission arrangement according to the invention, Figure lb shows a side view of a roller construction incorporating a transmission arrangement according to the invention, Figure 2 shows a cross-section, on planes A-A, of the roller on Figure 1b and its transmission arrangement, Figures 3a-3c show side views of a roller construction incorporating the transmission arrangement

according to the invention, dismantled into its principal components.

Figure la shows a simplified side view of a landfill compactor equipped with a transmission arrangement according to the invention. In this case, the compactor includes a chassis- steered base and roller frames 10 arranged in both of its chassis sections 12 and 12'. Cylindrical rollers 13 are supported in the end-pieces 11 of the roller frame 10, with the aid of two bearing assemblies. In rollers 13, there are also spinous protrusions 14, which improve the crushing and compacting effect of the landfill compactor. Hydraulic motor units (not shown) are also arranged to rotate the rollers 13.

The construction of a hydraulic motor unit is shown in greater detail in connection with Figure 2. In the front chassis section 12 there is a driving cab 15 and in the rear chassis section 12'there is an engine 16, with its ancillary devices and fuel tanks. In addition, one or more hydraulic pumps 17 are connected to engine 16, these being connected by suitable pipe lines to the hydraulic motor units arranged to rotate the rollers 13, in order to drive the compactor. The transmission arrangement according to the invention can also be applied to compactors other than landfill compactors.

Figure lb shows in greater detail one roller frame 10 and roller 13, which is supported rotatably in its end-pieces 11. In addition, only the outer row of protrusions 14 is shown. A cross-section of Figure lb is shown in Figure 2, which combines both a vertical and a horizontal cross-section.

According to the invention, the hydraulic motor unit of the compactor is a ready-made hub motor 18, which is as such known.

Alternatively, a conventional roller gear with a hydraulic motor installed in it, as shown in Figure 2, can be used. Other combinations are also possible. In hub motors, there is usually a planet gearbox, permitting the use of a high-speed standard

hydraulic motor, unless the hub motor itself already contains a motor. This substantially simplifies the compactor's transmission arrangement and simultaneously reduces the cost of purchasing and maintaining the compactor. In a known manner, hub motor 18 includes a casing 20 and a flange 21 as opposing attachment ends, with bearings 18'that axially secure the attachment ends set between them. According to the invention, the aforesaid bearings 18'also form the bearing assemblies of roller 13. This further simplified the construction of the compactor's transmission arrangement. Generally, roller 13 is supported from end-pieces 11 with the aid of the aforesaid hub motor 18, in such a way that one attachment end is secured to the end of roller 13 and the opposing attachment end is secured to end-piece 11.

According to the invention, the bearings 18'of hub motor 18 form precisely the bearing assemblies of roller 13. Thus, separate bearing assemblies are not required at the ends of the roller. In principle, the hub motor could be attached stiffly to both roller 13 and end-piece 11. However, when the compactor is driven, a wide roller will inevitably deflect to some extent, which will impose excessive stresses on the bearings of the hub motor. On account of this, according to the invention, hub motor 18 incorporates, in attachment end 20 or 21, an effective universal joint 22, which transmits a moment and permits a variation in angle. Thus, the bearings 18'of hub motor 18 are fully sufficient as the only bearing assemblies of roller 13.

The use of a hub motor and its axially securing bearings as the only bearing assembly of the roller is thus possible, because, according to the invention, roller 13 is supported from end- piece 11 through the effective universal joint 22. The universal joint also permits the variation in angle caused by the deflection of the roller, without excessively loading the bearings. Generally, there is a transmission arrangement

according to the invention in at least one end of each roller.

Thus, at the end without a motor, there is a simple bearing assembly, which permits a variation in angle. Preferably, self- aligning ball-like rolling bearings are used. The power of the compactor can be easily increased by arranging a hydraulic motor unit and universal joint at both ends of the roller.

There are various alternatives ways of attaching the hub motor.

The hub motor may be stiffly attached to the end plate of the roller, either by its casing or by a flange arranged to rotate in relation to it. Alternatively the hub motor may be stiffly attached to the end-piece either by its casing or by its flange. The roller gear 18 of Figure 2 is stiffly attached to end plate 23 of roller 13, so that most of the roller gear 18 is located inside end plate 23 of roller 13, where there is plenty of installation space. Threaded joints are preferably used for the attachment. The individual pairs of nuts and bolts are not shown.

According to the invention, the roller is supported from the end-pieces, by means of a hub motor and the effective universal joint connected to it. Generally, a universal joint with a known mechanism comprises two fork constructions and a crosspiece. However, the universal joint according to the invention is implemented in practice using components of various kinds. In this case, one fork construction is attached to one attachment end 20 or 21 of hub motor 18.

Correspondingly, the other fork construction is attached to the structure opposite to attachment end 20 or 21 of hub motor 18, in this case, to either end-piece 11 or end plate 23 of roller 13. In addition, the second fork construction is set at an angle of 90° to the first fork construction. The crosspiece 26 connected to the fork constructions is attached to each fork construction by means of two pairs of joints 28 and 28'. The pairs of joints 28 and 28'are additionally essentially on the same plane.

To create the universal joint, plate construction 24 is attached to flange 21. The plate construction symmetrically carries two joints set at a distance in relation from the axis of rotation of roller 13, forming the first pair of joints 28 for carrying crosspiece 26. In addition, end-piece 11 is supported symmetrically with the aid of two joints forming the second pair of joints 28'placed in relation to the projection of the axis of rotation of roller 13. The joints in question are in turn support with the aid of the aforesaid crosspiece 26.

Crosspiece 26 is preferably formed by a circular ring arranged around hub motor 18, which ring includes the joint pins 27 and 27'of the aforesaid pairs of joints 28 and 28'. Pairs of joints 28 and 28'are preferably ball joints, which form the effective bearings of the universal joint. In the example, the horizontal pair of joints 28'of the crosspiece is fitted by means of two securing devices 25 stiffly attached to the end- piece 11. Securing devices 25 are preferably in turn fitted to end-piece 11 by means of threaded joints. Instead of ball joints, some other support that permits the mutual movement of the crosspiece and the plate construction can be used. In Figure 2, crosspiece 26 is fitted to plate construction 24 on the roller 13 side, when the total length of the transmission arrangement will be as short as possible. Thus, a solution according to the invention will form a joint construction, which permits variation of the angle between the roller and the end-piece. The construction is, however, stiff in both the axial and radial directions and can transmit even large moment.

Various forces and moments are transmitted from the end-piece to the roller through the hub motor and the universal joint. In the example of a solution according to Figure 2, the force through the securing devices 25 attached to end-piece 11 is transmitted through the horizontal pair of joints 28'to crosspiece 26. From crosspiece 26, the force is transmitted in

turn through the vertical pair of joints 28 to plate construction 24. From plate construction 24, the force continues by means of flange 21 to casing 20 and from it in turn through end plate 23 to roller 13. Thus, the rotational movement of the hub motor is transmitted to the roller and the hub-motor bearings can be used as the only bearings, as the universal joint permits the variation of the angle of the roller.

Figures 3a-3c show a roller construction according to the invention and its principal components separated from one another. In Figure 3c shows roller 13, which has an opening 29 in its end plate 23 made for the hub motor. There is a suitable number of holes 30 drilled around opening 29 for attaching the hub motor to roller 13. In addition, end plate 23 is arranged to be slightly sunk inside roller shell 34, so that essentially the entire transmission arrangement will fit inside roller 13.

In Figure 3b, there is a component formed by hub motor 18 and universal joint 22, which can be assembled prior to the assembly of the actual compactor. In the example, the component is first attached by means of the hub motor to roller 13. Next, roller 13 and roller frame 10 are fitted together and securing devices 25 are attached to end-piece 11. For this purpose, a suitable number of holes 31 are drilled in end-piece 11 (Figure 3a). Ball joints 28'can be inspected and serviced through the smaller openings 32 in end-piece 11. In the example, hydraulic motor 19 protrudes from the larger opening 33 in end-piece 11.

A protective cap can be fitted over the large opening 33. In the same way, a protective cover 35, under which are the connections of hydraulic motor 19, can finally be placed over the entire end-piece 11.

The compactor transmission arrangement according to the invention is considerably simpler than previous arrangements.

It also allows the use of standard components, which facilitates the maintenance of the compactor. The transmission

arrangement also does not limit the maximum width of the roller. For example, instead of a universal joint, a flexible ring construction can be used, by means of which one attachment end of the hub motor is supported. Correspondingly, the universal joint can be replaced, for example, with a construction similar to a constant-angular-velocity joint. A solution according to the invention can also be used in connection with other things than the rollers described.

However, in compactor use, the simplicity and space-saving achieved are significant advantages.