WO2011087404A1

WO2011087404A1 - A heavy vehicle

Info

Publication number: WO2011087404A1
Application number: PCT/SE2010/000007
Authority: WO
Inventors: Andreas Lundmark
Original assignee: Volvo Lastvagnar Ab
Priority date: 2010-01-18
Filing date: 2010-01-18
Publication date: 2011-07-21

Abstract

The invention relates to a heavy vehicle (1) comprising a powertrain (4) for propelling the vehicle. The vehicle (1) comprises a first axle (2), which constitutes a drive axle and is arranged foremost in the vehicle, and a second axle (3), which is a non-drive axle. The powertrain (4) comprises a first propeller shaft (8) which is configured to transmit power from a position (13) rear of the second axle and forwards past the second axle (3) for driving the first axle (2) and that the first propeller shaft (8) extends through a hole in the second axle (3).

Description

A heavy vehicle FIELD OF THE INVENTION

The present invention relates to a heavy vehicle comprising a powertrain for propelling the vehicle.

The invention will below be described for a heavy vehicle in the form of a cargo-transporting road vehicle in the form of a truck. This should however only be regarded as one possible application and the invention may further be applied in a people- transporting vehicle, such as a bus, an agricultural machine or a work machine for transporting cargo, material, earth etc.

The invention is especially directed to a heavy vehicle with dual front axles and especially to a truck with dual front axles. In many countries/regions, there are set limitations in maximum pressure on a front axle, which leads to a trend towards using dual front axles for applications where the truck will carry heavy loads. Further, in applications where the ground conditions are poor, such as in slippery conditions, at least one of the front axles must be a drive axle. Thus, a truck with dual front axles results in high mobility off-road, especially adapted for applications in construction sites.

According to a known solution of such a truck with dual front axles, a first front axle (the foremost axle) constitutes a ηοη-drive· axle and the second front axle is a drive axle. Further, the truck comprises at least one further drive axle arranged rear of the second axle. The powertrain comprises a power source, which is arranged in a front part of the truck, a transfer gear box, which is arranged rear of the second axle and arranged to distribute power from the power source forwards to the second axle and rearwards to the further, rear drive axles via propeller shafts.

One problem with such a truck is that the steering is limited when driving the truck in poor ground conditions, such as in slippery conditions.

SUMMARY OF THE INVENTION

An object of the invention is to achieve a heavy vehicle (especially a truck) with dual front axles, which improves steering and simultaneously creates conditions for a combination of sufficient ground clearance and sufficient space for deflection of the vehicle's suspension system.

This object is achieved in a vehicle according to claim 1. Thus, it is achieved in that the vehicle comprises a first axle, which constitutes a drive axle and is arranged foremost in the vehicle, and a second axle, which is a non-drive axle, that the powertrain comprises a first propeller shaft which is configured to transmit power from a position rear of the second axle and forwards past the second axle for driving the first axle and that the first .propeller shaft extends through a hole in the second axle.

Thanks to the fact that the foremost axle is driven, conditions are created for a considerably improved steering. Further, the solution is space-efficient in that the first propeller shaft is directed through the second axle in contrast to arranging the first propeller shaft above the second axle (which would result in limited suspension travel) or arranging the first propeller shaft below the second axle (which would result in limited ground clearance) .

According to an example embodiment, the second axle comprises a bearing arranged in said hole and that the first propeller shaft is arranged in said bearing. Thus, the bearing is adapted to support the first propeller shaft during rotation, which implies a controlled operation .

According to a further example embodiment, the through hole in the second axle for the first propeller shaft is arranged in the vicinity of a portion configured for connecting the second axle to a suspension member. Said suspension member may be formed by a spring, such as a leaf spring, attached to the vehicle's frame. The through hole in the second axle forms a weakness and this position of the through hole is preferred due to the fact that it is a less strained part of the second axle compared to a position closer to the nearest wheel. Further, a more central space between the vehicle's frame's side members would interfere with the position of the gearbox and/or other propeller shafts.

According to a development of the last-mentioned example embodiment, the through hole for the first propeller shaft is arranged at least partly at an interior side of said portion configured for connecting the second axle to the suspension member. This is a particularly advantageous position with regard to the other components competing of the available space.

According to a further example embodiment, at least a portion of the second axle, which comprises the through hole is formed by a one-piece unit. Such a continuous piece creates conditions for an _.easy production and sufficient rigidness for withstanding the loads during operation. Preferably, said at least one portion of the second axle is formed by a forging.

Further preferred embodiments and advantages of the invention emerge from the other claims and the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained below, with reference to the embodiment shown on the appended drawings, wherein FIG 1 is a schematic side view of a truck with dual front axles according to an embodiment of the invention,

FIG 2 shows a perspective front view of the truck in figure 1,

FIG 3 shows a side view of the vehicle in figure 1 at.

the position of the dual front axles,

FIG 4 shows a view from above of the vehicle in figure 1 at the position of the dual front axles, FIG 5 shows a perspective view of the second front axle in figure 1, and

FIG 6 shows a bearing arrangement in the second front axle for accommodating a propeller shaft in figure 1. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Figure 1 shows a schematic side view of . a heavy duty vehicle in the form of a truck 1 with dual front axles 2,3 according to an embodiment of the invention. The truck 1 is of a type with a load carrying unit (not shown) directly attached to the frame of the tractive unit. The load carrying unit may be rigidly attached to the frame, a so-called fixed cargo platform or tippable relative to the frame, a so-called tippable platform.

The truck 1 comprises a first axle 2, which constitutes a drive axle and is arranged foremost in the vehicle, and a second axle 3, which is a non-drive axle. All terms used in the description with regard to positions, such as "foremost", "forwards", "rear", "interior" etc, relates to the relative position in the truck. The truck 1 comprises a powertrain 4 for propelling the vehicle. The powertrain 4 comprises a power source 5 in the form of an internal combustion engine (preferably a diesel engine) , which is arranged in a front part 6 of the vehicle 1 and which is adapted to transmit power to the first axle 2. Further, the powertrain 4 comprises a gearbox 7 operationally connected to an output shaft of the engine 5.

Further, the powertrain 4 comprises a first propeller shaft 8 which is configured to transmit power from a position 9 rear of the second axle 3 and forwards past the second axle 3 for driving the first axle 2. The vehicle 1 further comprises at least one further drive axle 10,11 arranged rear of the second axle 3. The powertrain 4 comprises a second propeller shaft 12, which is arranged to transmit power to said at least one further rear drive axle 10,11 in a direction rearwards from said position 9 rear of the second axle. More specifically, the powertrain 4^' comprises a device 13 for distributing power to the first propeller shaft 8 and to the second propeller shaft 12 and the power distributing device 13 (or transfer gearbox) is arranged in said position 9 rear of the second axle.

The powertrain 4 comprises a further propeller shaft 14 operationally connected between the gearbox 7 and the transfer gearbox 13. The powertrain 4 comprises a further propeller shaft 15 operationally connected between the transfer gearbox 13 and said first propeller shaft 8. The powertrain 4 comprises a further propeller shaft 16 operationally connected between said first propeller shaft 8 and the first axle 2. The first propeller shaft S is connected to the adjacent propeller shafts 15,16 via universal joints. Thus, the engine 5 is arranged to power the first axle 2 via said first powertrain transmission shaft 8. Each of the propeller shafts 8,14,12,15,16 extends in a- substantially longitudinal direction of the vehicle.

The truck comprises a forward control cab 17. Thus, the entire cab can be tilted forwards to provide access to the engine 5 for . service and maintenance.

The truck 1 comprises a frame 18, which comprises two longitudinal side members 19,20 (see figure 2.) at a distance, from, each other in a transverse direction of the vehicle. Each side member 19,20 has a U-shaped profile and the profiles are directed so that the U's are open towards each other. The side members 19,20 are united by a plurality of cross members, 21. The side and cross members are joined together by bolt or rivet fastenings. The side members 19,20 are provided with a hole configuration for attaching different components to the frame.

Figure 3 shows a side view of the vehicle 1 in figure 1 at the position of the dual front axles 2,3. The vehicle comprises a suspension member 22 in the form of a spring, which is rigidly attached to said first side member 19. The spring constitutes a leaf spring. More specifically, the suspension member 22 is elongated and extends substantially in parallel with the side member 19. The suspension member 22 is rigidly attached to the side member via brackets or other intermediate means at two positions at a distance from each other in the longitudinal direction of the first side member 19. The second axle 3 is rigidly attached to said first side member 22 at a position between the attachment points. Thus,, the second axle 3 is supported by the suspension member 22. The suspension arrangement is mirrored at the other side member 20.

Figure 3 further shows a first ground clearance A for the transfer gear box 13 and a second ground clearance B for the second axle 3. Further, figure 3 shows a suspension travel C.

Further, part of a steering system 23 is shown in figure 3. Both the first and second- axles 2,3 are steering axles. The steering system 23 comprises a first steering link 24 for steering the first axle 2 and a second steering link 25 for steering the second axle 3. Figure 4 shows a view from above of the dual front axles 2,3 corresponding to figure 3.

Figure 5 shows a perspective view of the second axle 3 in figure 1. The second axle 3 comprises at its respective ends 25,26 a bushing 27,28 constituting a bearing for a kingpin for supporting a wheel spindle. The second axle 3 comprises a through hole 29 for accommodating the first propeller shaft 8. A bearing 30 is arranged in said hole 29 and the first propeller shaft 8 is arranged in said bearing 30. The through hole 29 in the second axle 3 for the first propeller shaft 8 is arranged in the vicinity of a portion 31 configured for connecting the second axle 3 to the suspension member 22. The through hole 29 for the first propeller shaft 8 is arranged at least partly at an interior side of said portion 31 configured for connecting the second axle 3 to the suspension member 22. More specifically, the through hole 29 is positioned below the contact surface configured for contacting the suspension member 22.

A central section of the second axle 3 is defined by an upper surface 32 and a lower surface 33, which are substantially parallel to each other. The central section comprises said portion 31 configured for connecting the second axle 3 to the suspension member 22. The through hole 29 is positioned between the planes defined by said parallel surfaces 32,33. At least a portion of the second axle 3, which comprises the through hole 29 is formed by a one-piece unit. Preferably substantially the entire second axle 3 is formed by a one-piece unit. Said at least one portion of the second axle 3 is formed by a forging. In other words, the second axle is a one-piece forged unit. According to an alternative, said at least one portion of the second axle 3 is formed by a castings. Figure 6 shows a cross section of the bearing arrangement 30 in the second front axle 3 in figure 5.

Figure 4 shows that the second axle 3 is arranged so that the hole 29 is positioned in the vicinity of the first side member 19 in a view from above. More specifically, the through hole 29 for the first propeller shaft 8 is arranged at least partly at an interior side of the first side member 19 in the view from above .

The invention is not to be regarded as being limited to the illustrative embodiment described above, but a number of further variants and modifications are conceivable within the scope of the following patent claims.

For example, the invention is not limited to the type of truck shown in figure 1. Instead, the invention may for example be applied in a semi-trailer tractor, wherein a semi-trailer is adapted to be connected to the semi-tractor via a so-called fifth wheel.

Claims

1. A heavy vehicle (1) comprising a powertrain (4) for propelling the vehicle characterized in that the vehicle (1) comprises a first axle (2), which constitutes a drive axle and is arranged foremost in the vehicle, and a second axle (3), which is a non-drive axle, that the powertrain (4) comprises a first propeller shaft (8) which is configured to transmit power from a position (9) rear of the second axle and forwards past the second axle (3) for driving the first axle (2) and that the first propeller shaft (8) extends through a hole (29) in the second axle.

2. A vehicle according to claim 1, characterized in that the second axle (3) comprises a bearing (30) arranged in said hole (29) and that the first propeller shaft (8) is arranged in said bearing.

3. A vehicle according to claim 1 or 2, characterized in that the through hole (29) in the second axle (3) for the first propeller shaft is arranged in the vicinity of a portion (31) configured for connecting the second axle to a suspension member (22) .

4. A vehicle according to claim 3, characterized in that the through hole (29) for the first propeller shaft (8) is arranged at least partly at an interior side of said portion (31) configured for connecting the second axle to the suspension member.

5. A vehicle according to any preceding claim, characterized in that at least a portion of the second axle (3), which comprises the through hole (29) is formed by a one-piece unit.

6. A vehicle according to claim 5, characterized in that said at least one portion of the second axle (3) is formed by a forging.

7. A vehicle according to any preceding claim, characterized in that the vehicle comprises at least one further drive axle (10,11) arranged rear of the second axle ( 3 ) .

8. A vehicle according to claim 7, characterized in that the powertrain comprises a second propeller shaft (12), which is arranged to transmit power to said at least one further rear drive axle (10,11) in a direction rearwards from said position (9) rear of the second axle.

9. A vehicle according to claim 7 or 8, characterized in that the powertrain comprises a device (13) for distributing power to the first propelle.r shaft (8) and to the second propeller shaft (12)^' and that the power distributing device (13) is arranged in said position (9) rear of the second axle.

10. A vehicle according to any preceding claim, characterized in that the vehicle (1) is constituted by a truck with dual front axles and that the dual front axles comprise the first axle and the second axle.