The invention relates to axle and bogie con¬ structions according to the preambles of claims 1 and 2 for commercial vehicles, in particular lorries and trailers.

Rigid steering axles are used in especially heavy transports, in which it is necessary that one or some of the axles provided with twin wheels are steer- able, as there are typically more than two such axles and as the turning radius of the vehicle is inadequate without steering. Rigid axles are used because of the heavy load and simple construction. It is also crucial that the load is evenly distributed on all axles in uneven terrain.

It is customary to use twin wheels supported by separate springs, in which case the construction meets both the turning and load distribution requirements.

It is also possible to use axles journalled fixedly to the frame by means of a turntable. The turn¬ ing requirements are thereby met, whereas the load dis¬ tribution requirements will not be fulfilled if there are several axles, since the support springs of the axles used in connection with the turntable are not interconnected.

Further, various load distribution arrangements comprising a number of trailers are known. A problem therewith is the poor manageability of the combinations.

It is also known to use twin wheels each supported by separate springs and each having a separate turntable and wheels that turn easily even through 180° .

In this case, however, the wheels cannot be driven mechanically, wherefore hydraulic motors are used in most cases. This solution is both complicated and expensive.

Finnish Patent Application No. 901498 discloses solutions similar to those defined in the preambles of claims 1 and 2. In these'solutions the axle is arranged to be turned by affecting the position of the longitudinal supports of the axle and the suspension rods of the springs. These arrangements succeed well in fulfilling the requirements set for the control of the turning behaviour of the axle, the distribution of the load and the interaction between successive axles in multiple-axle bogie constructions. Inthis construction, however, no long springs or other long support means can -be used, because the support means turn together with the axles, and only relatively short support means have sufficient turning space. Owing to short support means, on the other hand, all components relating to axle suspension have to be disposed crampedly close to one another.

The object of the present invention is to resolve the above-mentioned problem and produce an advantageous effect on the loading of the components. This object is achieved by means of the axle constructions of the invention, which are characterised by what is disclosed in the characterising portions of claims 1 and 2, This construction makes it possible that the support means or springs always remain parallel with the chassis frame of the vehicle, which thus enables the use of support means or springs of a desired length.

The bogie may comprise, and it normally does, more than two axles, and some of the axles may be dead, i.e. not steering. In general, at least one axle is a dead axle. At least the following alternatives are obvious:

- A bogie formed by one steering axle and one dead axle. An equaliser lever is used and the support

means of the dead axle is supported at one end to the equaliser lever by means of a suspension rod, its other end being supported to the chassis frame in the same or another manner. - A bogie formed by two steering axles and one dead axle. In this case, the dead axle may be positioned at either end of the bogie, whereby the situation is the same as above, except that the equaliser lever is used between the steering axles, or as the middle axle of the bogie, whereby the dead axle is sprung to both steering axles by means of equaliser levers.

- A bogie formed by three steering axles and one dead axle.

- A bogie formed by one steering axle and two dead axles.

- A bogie formed by two steering axles and two dead axles.

- A bogie formed by three steering axles and two dead axles. - A single steering axle, whereby the equaliser lever is omitted and the suspension rods are secured at the lower end to the points of attachment of the chassis frame. This alternative is not a bogie con¬ struction even though the axle support and control of the invention are utilised.

It is to be understood that other alternatives can be realised by means of the bogie arrangement of the invention as well.

In the following the invention will be described in greater detail by means of two specific embodiments with reference to the—attached drawings, where

Figure la is a side view of a bogie construc¬ tion of the invention;

Figure lb is a top view of the construction of Figure la;

Figure lc is a rear view of the construction of Figure la; Figure 2a is a side view of the construction of the preceding figures when the axle is in a turned posi¬ tion;

Figure 2b is a top view of Figure 2a; and Figure 3 illustrates a single-axle construction according to the invention as shown in Figure la.

In Figures 1 and 2, the reference numeral 2 indicates an axle beam which may be the axle beam of a drive axle or an axle which is load-bearing only.

The reference numeral 15 indicates wheels which usually in heavy-load axles are twin wheels but may also be single wheels.

A triangular support 5 is attached resiliently to a chassis frame 1 of a vehicle or journalled thereto by means of joints 11. It is also attached centrally to the upper side of an axle beam 2 by means of a ball joint 10. This way of support allows the axle 2 to move resiliently in the vertical direction or to pivot in the vertical plane, in addition to which it allows a steering pivoting movement in the horizontal plane, whereas it prevents the movement of the axle sidewardly of the vehicle.

Support means 3 between the axle beam 2 and the chassis frame 1, which may be rigid levers or springs, such as leaf springs or parabolic springs, are attached centrally to the axle beam by means of joints 4 and at its ends similarly to the upper end of suspension rods 7 by means of ball joints 13 and 14. The rearmost suspension rods are attached at their lower end to the chassis frame 1 by means of ball joints 16 and the

foremost suspension rods similarly to the end of equaliser levers 9 by means of ball joints 17.

The means used for turning the axle beam 2 may be for instance as disclosed in Finnish Patent Application No. 901498, where the axle beam 1 turns around the attachment point of the triangular support 5 journalled thereto by moving back and forth longitudinal supports 6 attached to the axle beam 2 by means of joints 12. Joints 4 are such as allow the axle beam 2 to turn in the horizontal plane (in the plane of Figures lb and 2b) relative to support means 3 and the support means 3 to rock relative to the axle beam 2.

The suspension rods 7 for their part are mounted symmetrically in relation to the chassis frame 1.

This kind of securing of the support means 3 enables, despite the turning of the axle 2, the use of long support means, as the support means always remains parallel to the chassis frame 1.

The support means 3 tends to turn together with the axle beam 2 by the effect of joint friction, but the turning is resisted by force components which depend on the position of the suspension rods 7, operate at the ends of the support means, and are perpendicular to the direction of the chassis frame 1. By the effect of said force components the support means 3 remains almost parallel to the chassis frame 1.

The support means 3 may be part of a turning multiple-axle bogie construction or the suspension construction of a single turning axle.

Securing which allows the turning of the support means in the plane of Figure lb may be realised in a number of ways. An axial bearing, a ball-like

bearing or a resilient component allowing turning, such as a rubber or helical spring, can be used.

During the turning, the suspension rods 7 are pivoted away from their vertical position as shown in Figures 2a and 2b, whereby the chassis frame 1 of the vehicle rises. The tendency of the rods 7 to return to the vertical position due to the weight of the vehicle causes the steering to be subjected to a moment which returns it to the position for driving straight ahead, which has a stabilising effect on the steering.

The equaliser levers are mounted similarly centrally on an equaliser lever axle (not shown) which is attached to the chassis frame 1.

The other end of the equaliser levers 9 is connected to the support means of another axle by means of joints (not shown) corresponding to joints 17 and other suspension rods (not shown), which other axle may be steering or non-steering. In addition, either one, neither or both of the axles of the bogie may be a driving axle, whereby the rest are merely load-bearing axles as shown in the figures.

The equaliser levers preferably distribute wheel loads between the axles interconnected by means of them. In cases where both bogie axles are driving, it is possible in the construction of the invention that the drive of the rearmost steering and driving axle is advantageously effected through a cardan shaf connected between the axles.

In a construction comprising a single axle (Figure 3), which is steering, the equaliser levers are omitted as being unnecessary, and the suspension rods 7 are attached to the chassis frame 1 similarly to the rearmost suspension rods of Figures la and lb by means of a support 8.

The arrangement of the invention has been described above by means of two exemplifying arrangements only, and it is to be understood that the invention may be modified without deviating from the scope of protection defined in the attached claims, and it can be applied in various axle constructions, of which only a few possible examples have been mentioned in the foregoing.