Background Heavy vehicles, e. g. trucks, often have a bogie which is resiliently suspended relative to the vehicle's frame by means of a leaf spring arrangement.

One type of bogie is the balance tandem, i. e. a bogie which has two shafts (which may be powered or unpowered) and is provided with a spring fastening comprising a leaf spring package and a spring seat. To enable assembly, there is lateral clearance between the leaf spring package and the spring seat (see Figure 1). Owing to long tolerance chains, the clearance cannot be eliminated without causing assembly problems.

One problem with spring fastenings of this kind is that the leaf spring package and the spring seat may cause noise in the form of a loud bang on sharp bends at low speed.

This is because the leaf spring package retains the vehicle's wheelshaft laterally via the spring seat and the friction between the spring seat and the underside of the leaf spring package on sharp bends at low speed causes a preloading to build up until the friction can no longer restrain the leaf spring package, whereupon the leaf spring package jumps sideways towards the spring seat on the side of the leaf spring package which faces towards the centre of the vehicle. The result is a loud bang. During normal operation, the outside of the leaf spring package does not come into contact with the spring seat.

Brief description of the invention The problem of the leaf spring package and the leaf seat causing noise in the form of a loud bang on sharp bends at low speed is solved according to the invention by arranging a spring fastening which comprises a leaf spring package and a spring seat whereby the leaf spring package is arranged, on at least one of its sides, so as to abut, without clearance, against the spring seat by the leaf spring package and the spring seat having mutually adapted inclined side surfaces at the abutment point.

The fact that the spring fastening exhibits the characteristics of claim 1 affords the advantage that the leaf spring package and the spring seat no longer cause noise in the form of a loud bang on sharp bends at low speed, since the inclined side surfaces make it possible to eliminate the clearance between the leaf spring package and the spring seat without causing assembly problems. This is because the long tolerance chains no longer present any problem, since the leaf spring package will be pressed down into the spring seat by the weight of the vehicle frame during assembly even if there is less engagement between the leaf spring package and the spring seat.

Brief description of the drawings The invention is explained further below with reference to the attached drawings, in which: Figure 1 depicts schematically a section of a known traditional spring fastening for a vehicle bogie according to a first embodiment of the invention, Figure 2 depicts schematically a perspective view of a vehicle bogie, Figure 3 depicts schematically a section of a spring fastening during assembly according to a first embodiment of the invention,

Figure 4 depicts schematically a section of an assembled spring fastening according to a first embodiment of the invention, Figure 5a depicts schematically a perspective view of a leaf spring package of a traditional kind, and Figure 5b depicts schematically a perspective view of a leaf spring package according to a first embodiment of the invention.

Description of preferred embodiments Figure 1 depicts schematically a section of a known traditional spring fastening 2 for a vehicle bogie. The spring fastening 2 comprises a leaf spring package 4 and a spring seat 6, whereby the leaf spring package 4 is arranged with clearance 8,10 relative to the spring seat 6, as viewed in the vehicle's transverse direction.

Figure 2 depicts schematically a perspective view of a vehicle bogie 12 according to a first embodiment of the invention. As the vehicle bogie is symmetrical, when viewed in the vehicle's longitudinal direction, only one side of the vehicle bogie is depicted.

The vehicle bogie 12 comprises according to this embodiment two wheelshafts 14,16 and two leaf spring packages 18,20 (only one of which, 18, is visible in the drawing).

The two wheelshafts 14 and 16 respectively are fastened to the vehicle frame 22 via guide rods 24,26, 28 and 30,32, 34 respectively (one of which, 28, is not visible in the drawing). The leaf spring packages 18 and 20 respectively are fastened to the vehicle frame 22 via bearings 36 and 38 respectively (only one of which, 36, is visible in the drawing), about which the leaf spring packages 18 and 20 respectively can pivot. The wheelshafts are provided with spring seats 40,42, 44,46 (only two of which, 40,44 are visible in the drawing) whereby each spring seat 40,42, 44,46 is intended to accommodate one of the end regions 48,50, 52,54 (only two of which, 48,52, are visible in the drawing) of the leaf spring packages 18,20. When the wheelshafts 14,16 and the leaf spring packages 18,20 are assembled together, they are thus connected to one another at spring fastenings 56,58, 60,62 (only two of which, 56,60, are visible in

the drawing) comprising the spring seats 40,42, 44,46 of the wheelshafts 14,16 and the end regions 48,50, 52,54 of the leaf spring packages 18,20. The bearings 36 and 38 respectively are preferably situated centrally between the two wheelshafts 14,16.

Figure 3 depicts schematically a section of a spring fastening 56,58, 60,62 during assembly according to a first embodiment of the invention. The spring fastening 56,58, 60,62 comprises a spring seat 40,42, 44,46 of a wheelshaft 14,16 and an end region 48,50, 52,54 of a leaf spring package 18,20. As may be seen, the spring seat 40,42, 44,46 of the wheelshaft 14,16 and the end region 48,50, 52,54 of the leaf spring package 18,20 have mutually adapted inclined side surfaces 64,66.

Figure 4 depicts schematically a section of an assembled spring fastening 56,58, 60,62 according to a first embodiment of the invention. The spring fastening 56,58, 60,62 comprises a spring seat 40,42, 44,46 of a wheelshaft 14,16 and an end region 48,50, 52,54 of a leaf spring package 18,20. As may be seen, the end region 48,50, 52,54 of the leaf spring package 18,20 is arranged, on at least one of its sides 68, to abut, without clearance, against the spring seat 40,42, 44,46 of the wheelshaft 14,16 by the end region 48,50, 52,54 of the spring leaf package 18,20 and the spring seat 40,42, 44,46 of the wheelshaft 14,16 having mutually adapted inclined side surfaces 64,66 which abut against one another at an abutment point 70 situated on the side of the leaf spring package 18,20 which faces towards the centre of the vehicle, i. e. the inside of the leaf spring package 18,20 rests against the spring seat 40,42, 44,46.

During normal operation, the outside of the leaf spring package 18,20 does not come into contact with the spring seat 40,42, 44,46 according to this first embodiment of the invention.

The long tolerance chains no longer present any problem when assembling the spring fastening 56,58, 60,62, since the end region 48,50, 52,54 of the leaf spring package 18,20 will be pressed down into the spring seat 40,42, 44,46 of the wheelshaft 14,16 by the weight of the vehicle frame during assembly even if there is less engagement (and hence a preloading of the leaf spring package 18,20) between the end region 48,50, 52,54 of the leaf spring package 18,20 and the spring seat 40,42, 44,46 of the

wheelshaft 14,16. Accordingly it is possible on the basis of said inclined side surfaces 64,66 to eliminate the clearance between the end region 48,50, 52,54 of the leaf spring package 18,20 and the spring seat 40,42, 44,46 of the wheelshaft 14,16 without causing assembly problems, with the result that the leaf spring package and the spring seat no longer cause noise in the form of a loud bang on sharp bends at low speed.

The end region 48,50, 52,54 of the leaf spring package 18,20 is retained horizontally in the spring seat 40,42, 44,46 of the wheelshaft 14,16 by a locking pin 72 which is arranged at a distance 74 from the end region 48,50, 52,54 of the leaf spring package 18,20 in order to allow vertical resilient movements of the leaf spring package 18,20.

Figure 5a depicts schematically a perspective view of a leaf spring package 76 of a traditional kind, with horizontal side surfaces 78.

Figure 5b depicts schematically a perspective view of a leaf spring package 18,20 according to a first embodiment of the invention, with inclined side surfaces 64 which are preferably made by milling a traditional leaf spring package 76.

The preferred embodiment exemplifies a leaf spring package 18,20 with four springs 80,82, 84,86, but the number of springs may be one or more in a leaf spring package according to the invention.