WO2000073125A1

WO2000073125A1 - Four-wheel drive motor vehicle with articulated vehicle steering

Info

Publication number: WO2000073125A1
Application number: PCT/AT2000/000156
Authority: WO
Inventors: Friedrich Erlebach
Original assignee: Zf Friedrichshafen Ag
Priority date: 1999-06-01
Filing date: 2000-05-31
Publication date: 2000-12-07
Also published as: EP1181185A1

Abstract

The invention relates to a four-wheel drive motor vehicle, wherein the front carriage and the rear carriage are movably connected to one another by means of a center pivot steering (7, 26) and a roll articulation (9) and the drive train comprises a motor-transmission unit (11), a transfer case (14) and driven axles (3, 6, 6'; 23), which are connected to one another by means of articulated shafts or to the transfer case. The invention aims at further improving handling performance and operational safety of said vehicle. To this end, the roll articulation (9) is disposed behind the center pivot steering (7, 26) and the transfer case (14) is mounted in an intermediate section (8) between the center pivot steering (7, 26) and the roll articulation (9). The front carriage (1) and the rear carriage (4) are connected to one another by means of the intermediate section (8) in which the transfer case (14) is mounted.

Description

MOTOR VEHICLE WITH ALL-WHEEL DRIVE AND ARTICULATED STEERING

The invention relates to a motor vehicle with all-wheel drive and articulated steering, consisting of a front end, a rear end and a drive train, the front end and the rear end being movably connected to one another via an articulated joint and a roller joint, and the drive train comprising a motor transmission unit, a transfer case and driven axes, which are connected to each other by cardan shafts.

Motor vehicles with all-wheel drive and articulated steering are mainly used as heavy-duty construction vehicles, with the driver's cab, the motor-gear unit and the hydraulic unit required for steering, among other things, on the front end and a large body with hydraulic tipping device on the rear end. The front end has an unguided, driven, rigid front axle, while the rear end usually has two rear axles that are also arranged in tandem. In addition to the articulated joint, a roller joint is also required between the two vehicle parts in order to allow the axles to be set off-road.

When designing such a vehicle, three problem areas have to be considered in particular: first, the rigidity of the articulated joint and the roller joint; secondly, the driving characteristics (safety against tipping, cornering with regard to steering stability as well also drive uniformity); and thirdly, the operational safety of the line connections (hydraulic and electrical) between the front and rear section. The first requires a long vertical articulation axis; the second, above all, the shortest possible front end, and the third, minimizing and protecting the connection cables. All of these place demands on the planning of the drive train.

In generic vehicles known from practice, the transfer case is housed throughout in the front end. This lengthens the front end and complicates the final drive because the short distance to the front axle requires an extremely short drive shaft, which affects the uniformity of the drive, and because the drive connection to the rear end has to overcome the articulated joint and the roller joint.

With the dump truck from VOLVO, the articulated joint and roller joint are provided on almost the same length of the vehicle, the former somewhat before the second, and - due to the shortness of the front end - very close to the transfer case. This results in an extremely short PTO shaft due to the articulated joint with its known disadvantages.

In the MOXY dump truck, the roller joint is located in front of the articulated joint, which also requires an extremely short PTO shaft and also an arrangement of the steering cylinders behind the roller joint, which requires the hydraulic hoses to be guided over both joints; they are so exposed, heavily used and tear when the vehicle tilts. This version reduces the tipping stability because considerable reaction forces are introduced into the front body when turning and rolling the rear body.

It is therefore the aim of the invention to design generic vehicles in such a way that an optimal solution is found in the three problem areas listed above, that is, above all, good driving properties with high operational safety, for which purpose the articulation axis should be as far forward as possible. The solution according to the invention is that the roller joint is arranged behind the articulated joint and the transfer case is arranged in an intermediate section between the articulated joint and the roller joint. The transfer case is therefore behind the articulated joint, which enables the short front end (without extremely short cardan shafts) that is desirable for the steering and driving behavior. The short kink length achieved in this way is not only particularly advantageous for the driving properties. It also allows longer cardan shafts, especially to the rear. As a result, the deflection angle of the cardan shaft caused by the difference in height is smaller, or the total wheelbase can be shortened, or there is still room for a parking brake in the rear section.

In addition to the hydraulic system, the steering cylinders and emergency steering can also be accommodated on the front end. It is therefore no longer necessary to run vulnerable steering hoses over the joints, only the hydraulic lines for tipping the trough have to be guided through the roller joint.

In a preferred embodiment, the front carriage and the rear carriage are connected to one another via the intermediate wing which forms part of the articulated joint at the front and part of the roller joint at the rear and in which the transfer case is mounted (claim 2). The intermediate tract is in any case as long as the transfer case, it can therefore be generously dimensioned and thus also allows a strong design of both joints; the articulated joint with a large vertical extension and the roller joint with a large horizontal extension. Because of the latter, the internal rotary entries for the hydraulic line to the tipping cylinders of the body are easy.

In a further development of the invention with regard to the drive train, the transfer case of which has an input shaft and a front and a rear output shaft, the input shaft is connected to the motor gear unit and the front output shaft is connected to the front axle via a universal joint shaft and the rear output shaft is connected to the roller joint in Essentially coaxial (claim 3). The first two cardan shafts run through the articulated joint, which, due to the kinematically favorable W constellation of the cardan shafts, does not ensure the uniformity of the drive impaired, and the output shaft can be beautifully supported in the roller joint without limiting its length.

In an advantageous development, the rear output shaft of the transfer case is arranged higher than the front output shaft (claim 4). This allows a structurally favorable design of the intermediate wing and the frame parts of the rear end adjoining it at the rear with the propeller shaft arranged deeply to the front axle. As a result, the articulated joint can again be particularly high and stiff.

To refine the invention, the cardan shafts between the motor gear unit and transfer case and between the transfer case and the front axle are approximately halved by the axis of the articulated joint (claim 5). The deflection angles at both joints of the cardan shafts are always the same, which always ensures the ideal W constellation and thus the uniformity of the drive.

Finally, it is still within the scope of the invention to make the front axle rigidly connected to the front carriage, the wheels on which are individually guided vertically (claim 6). The PTO shaft between the transfer case and the front axle differential attached to the front end is then only exposed to changes in angle in the horizontal plane (W constellation) and no longer at all to the less kinematically more favorable in the vertical plane (Z constellation).

The invention is described and explained below with the aid of figures. They represent:

Fig. 1: A partial side view of the vehicle according to the invention, Fig. 2: A partial top view of the vehicle according to the invention, Fig. 3: An enlarged side view in a first variant, Fig. 4: An enlarged side view in a second variant.

In Fig.l, 2, the front car is summarized with 1 and the rear car with 4 summarily. The frame 2 of the front carriage 1 carries a front axle 3 which Support body 5 of the rear carriage 4 has at least one, but usually two rear axles 6, 6 '. All axles are driven, the steering is done by moving the two parts to each other about a vertical axis. For this purpose, an articulated joint 7 is provided. It forms a vertical axis in the middle of the vehicle, the articulation axis. 5 In front of the articulation axis is the front car, behind it an intermediate wing 8, the front end of which forms part of the articulated joint 7 and the rear end of which is a roller joint 9, which allows front car 1 and rear car 4 to be rotated relative to one another about a vertical axis. In terrain, it interlaces the axles, which are hardly or not at all sprung, against each other. The roll axis is designated 10 10.

In the frame 2 of the front end 1, a motor transmission unit 11 is mounted in the known manner, the drive train emanating from it further consists in an intermediate shaft 12, a first universal joint shaft 13 bridging the articulated joint 7, one on it

15 subsequent transfer case 14 and finally a second drive shaft 15 leading to the front axle and a propeller shaft 16 leading to the rear axle (s) 6. The two drive shafts 13, 15 are arranged in the center and are halved in length by the axis of the articulated joint 7. In the embodiment shown, the front axle is a rigid axle, which is resiliently supported on the frame 2 and is

20 rods 17 is guided. It is essential for the invention that the articulated joint 7 is arranged at a considerable distance 18 in front of the roller joint 9.

3 shows the essential parts enlarged, whereby in a variant of Fig.l, 2, the frame 2 of the front end has a downward-extending axle bracket 20, with which an axle differential 21 of the front axle 23 is fixedly connected. The wheels themselves can then be guided in a known manner by wishbones, not shown, and driven by further drive shafts, not shown, independently suspended. Otherwise everything is as in FIGS. 1, 2.

30 The intermediate tract 8 is a rigid body and is usually designed as a steel structure. On its front end face it has ears 29 which are connected by bolts 26, 28 form an upper pivot bearing 25 and a lower pivot bearing 27. The distance between these two articulated bearings 25, 27 should be as large as possible.

The intermediate tract 8 receives the transfer case 14. For this purpose, it has bearing blocks, not shown, in which the transfer case is supported, either completely or via silent blocks, not shown. In order to obtain the longest possible drive shafts 13, 15, the transfer case 14 is preferably moved backwards in the intermediate piece. In this way, the input shaft 30 of the transfer case 14 is very far behind, and the first propeller shaft 13 can be made relatively long.

10

Furthermore, the transfer case has a front output shaft 31 to which the second propeller shaft 15 connects and a rear output shaft 32 to which the cardan shaft 16 connects for driving the rear axles. The front output shaft is advantageously as deep as possible, at the level of the front axle 3, and the rear output shaft

15 32 slightly higher, in the roll axis. In the exemplary embodiment shown, this results in a supporting part 5 of the rear end 4 which is just connected to the roller joint 9 and a ground clearance which is only slightly impaired by the cardan shaft 16. The height difference between the two output shafts 31, 32 is designated 33. The design of the roller joint 9 is not shown in more detail because different designs are known and the spatial conditions are only slightly limited due to the invention.

The embodiment of Figure 4 differs from the previous one in that the transfer case 40 has the two output shafts 41, 42 to the front and rear axles at the same height. The steering mechanism and the other connections

25 lines between the front and rear car are not shown in detail. Because the articulated joint is arranged in front of the roller joint, the master steering cylinders (not shown) can be fixedly arranged on the front end. The transfer case arranged in the intermediate tract 8 can, for example, have a flanged-on oil pump 43 for the tilting hydraulics of the trough, which pressurizes the pressure medium via a not shown

30 because it is known to provide rotary entry to the rear end.

The invention favors various designs and arrangements of the hydraulics. For example, the entire hydraulic system, including the steering hydraulics, can be located in the intermediate wing housed and driven from the transfer case. As a result, connecting hoses for pressure oil are no longer required if the connection to the rear carriage is made via rotary entries. This means that even a rollover of the rear end cannot put the hydraulics out of operation.

Claims

PATENT CLAIMS

1. Motor vehicle with all-wheel drive and articulated steering, consisting of a front end (1) with a front axle (3; 23), a rear end (4) with at least one rear end (6,6 ') and a drive train, the front end and the rear end are movably connected to one another via an articulated joint (7) and a roller joint (9) and the drive train consists of a motor gear unit (11), a transfer case (14) and driven axles (3,6,6 '; 23), each of which are connected to one another or to the transfer case by cardan shafts, characterized in that the roller joint (9) is arranged behind the articulated joint (7) and the transfer case (14) in an intermediate section (8) between the articulated joint and the roller joint.

2. Motor vehicle according to claim 1, characterized in that the front end (1) and rear end (4) are connected to one another via the intermediate wing (8), which forms part of the articulated joint at the front and part of the roller joint at the rear and in which the transfer case (14) is stored.

3. Motor vehicle according to claim 2, characterized in that the transfer case (14) has an input shaft (30) and a front (31; 41) and a rear (32; 42) output shaft, the input shaft (30) with the engine Gear unit (11) and the front output shaft (31; 41) are each connected to the front axle via a cardan shaft (13J5) and the rear output shaft (32; 42) with the roller joint (9) is essentially coaxial.

4. Motor vehicle according to claim 3, characterized in that the rear output shaft (32) is arranged higher than the front output shaft (31).

5. Motor vehicle according to claim 3, characterized in that the drive shafts (13J5) between the motor gear unit (11) and transfer case (14) and between transfer case (14) and the front axle (3; 23) from the axis of the articulated joint (7) be cut in half.

6. Motor vehicle according to claim 1, characterized in that the front axle (23) is rigidly connected to the front car (1) and the wheels are individually vertically movable on this.