A WORKING MACHINE

Abstract

A working machine includes a first side, a second side arranged opposite to the first side. a dump body, a working machine frame, and at least one tilting actuator. The at least one tilting actuator may arrange the working machine in a load dumping state. The working machine further includes a first propulsion axle arranged in the first side, a second propulsion axle arranged in the second side, a first propulsion axle suspension arrangement arranged between the first propulsion axle and the working machine frame; and a second propulsion axle suspension arrangement arranged between the second propulsion axle and the working machine frame. In the load dumping state the second propulsion axle suspension arrangement is stiff.

Claims

1. A working machine having a first side and a second side arranged opposite to the first side, the second side being a load dumping side, the working machine comprising: a dump body for receiving a load; a working machine frame for supporting the dump body; at least one tilting actuator connecting the working machine frame and the dump body, wherein in a load dumping state, the dump body is tiltable by means of the at least one tilting actuator in order to discharge the load from the dump body; a first propulsion axle arranged the first side of the working machine; a second propulsion axle arranged in the second side of the working machine; a first propulsion axle suspension arrangement arranged between the first propulsion axle and the working machine frame; and a second propulsion axle suspension arrangement arranged between the second propulsion axle and the working machine frame, wherein in the load dumping state, the second propulsion axle suspension arrangement bottoms out becomes stiff.

2. A working machine according to claim 1, wherein the second propulsion axle suspension arrangement has a second propulsion axle damping characteristic, wherein the second propulsion axle damping characteristic is defined by an ability of the second propulsion axle suspension arrangement to suspensionally take up a load from the second propulsion axle and/or the working machine frame, and wherein in the load dumping state, the second propulsion axle damping characteristic is substantially zero.

3. A working machine according to claim 2 , wherein the first propulsion axle suspension arrangement has a first propulsion axle damping characteristic which is different from the second propulsion axle damping characteristic.

4. A working machine according to claim 1, wherein the first propulsion axle suspension arrangement has a larger suspension ability compared to the second propulsion axle suspension arrangement.

5. A working machine according to claim 1, wherein the dump body comprises a first end portion and a second end portion arranged on the opposite side to the first end portion, the second end portion being a load dumping end portion which is pivotally arranged to the working machine frame, wherein the at least one tilting actuator is connected to the dump body such that in the load dumping state, the first end portion of the dump body is lifted.

6. A working machine according to claim 1, wherein the second propulsion axle suspension arrangement comprises at least one projection arm extending from the second propulsion axle towards the working machine frame, and a suspension cushion arranged between the projection arm and the working machine frame, wherein the suspension cushion is configured to suspensionally take up a threshold load.

7. A working machine according to claim 6, wherein in the load dumping state, the suspension cushion is configured such that when a load from the working machine frame to the second propulsion axle suspension arrangement exceeds the threshold load, the load from the working machine frame is taken up substantially by the at least one projection arm.

8. A working machine according to claim 1, wherein the first propulsion axle has an elongated main body comprising a first end portion, a second end portion and a center portion arranged between the first end portion and the second end portion, each one of the first end portion and the second end portion being adapted to be equipped with a propulsion hub for driving a working machine propulsion means, the elongated main body having a main body length extending from the first end portion to the second end portion, and wherein the first propulsion axle suspension arrangement comprises a first suspension device and a second suspension device arranged on opposite sides of a center of the elongated main body, and wherein the first suspension device and the second suspension device are arranged in the center portion.

9. A working machine according to claim 8, wherein the center portion is centrally arranged on the elongated main body, and is delimited to be at most 50% of the main body length.

10. A working machine according to claim 8, wherein the first suspension device is arranged closer to the center of the elongated main body than to the first end portion of the elongated main body, and the second suspension device is arranged closer to the center of the elongated main body than to the second end portion of the elongated main body.

11. A working machine according to claim 8, wherein a roll axis of the first propulsion axle is centrally positioned between the first suspension device and the second suspension device.

12. A working machine according to claim 1, further comprising: a first linkarm arrangement pivotably connecting the first propulsion axle with the working machine frame such that a roll axis of the first propulsion axle relative the working machine frame is comprised in the first linkarm arrangement; and a second linkarm arrangement pivotably connecting the second propulsion axle with the working machine frame such that a roll axis of the second propulsion axle relative the working machine frame is comprised in the second linkarm arrangement, wherein at least a respective portion of the first linkarm arrangement and the second linkarm arrangement comprising a respective roll axis is positioned above a respective center portion of the first propulsion axle and the second propulsion axle.

13. A working machine according to claim 12, wherein a ratio of a first parameter A defined as a shortest distance between a center of the first propulsion axle and the roll axis of the first propulsion axle, and a second parameter B defined as a shortest distance between a center of the first propulsion axle and the ground is between 0.35 and 1.0, and/or wherein a ratio of a third parameter C defined as a shortest distance between a center of the second propulsion axle and the roll axis of the second propulsion axle, and a fourth parameter D defined as a shortest distance between the center of the second propulsion axle and the ground is between 0.35 and 1.0.

14. A working machine according to claim 13, wherein the shortest distance between the center of the first propulsion axle and the roll axis of the first propulsion axle is between 200 mm and 500 mm, and/or wherein the shortest distance between the center of the second propulsion axle and the roll axis of the second propulsion axle is between 200 mm and 500 mm.

15. A working machine according to claim 12, further comprising first and second propulsion hubs for driving a working machine propulsion means, and wherein the roll axis for the first propulsion axle coincides with the roll axis for the second propulsion axle, and wherein a coinciding roll axis is positioned horizontally above respective upper ends of the first and second propulsion hubs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0078] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

[0079] In the drawings:

[0080] FIG. 1 is a perspective view of a working machine according to one embodiment of the invention.

[0081] FIG. 2 is a side view of a working machine according to one embodiment of the invention.

[0082] FIG. 3 is a front view of a working machine according to one embodiment of the invention.

[0083] FIG. 4 is a perspective view of a portion of the working machine including a propulsion axle according to one embodiment of the invention.

[0084] FIG. 5 is a side view showing the first and second propulsion axle suspension arrangements of a working machine according to one embodiment of the invention.

[0085] FIG. 6 is a side view of the working machine of FIG. 5 but in a load dumping sate, according to one embodiment of the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

[0086] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled addressee. Like reference characters refer to like elements throughout.

[0087] In the following, a working machine 1 is described. The inventive concept is applicable on any working machines within the fields of industrial construction machines or construction equipment, in particular dumpers/haulers. Although the invention will be described with respect to a hauler, the invention is not restricted to this particular machine, but may also be used in other working machines such as articulated haulers, excavators, backhoe loaders and wheel loaders.

[0088] As seen in FIG. 1 the working machine comprises a dump body 30 for accommodating a load. Merely as an example, and as is indicated in FIG. 1, the dump body 30 may be a loading platform of the working machine 1. The working machine 1 is adapted to have a load receiving condition in which the dump body 30 comprises an open load receiving area 31 outwardly delimited by a load receiving area circumference 34. In FIG. 1 an embodiment is shown where the working machine 1 is adapted to assume the load receiving condition in a normal state. In other words, the working machine 1 embodiment illustrated in FIG. 1 comprises a dump body 30 which always comprises an open load receiving area 31 outwardly delimited by a load receiving area circumference 34. However, it is also envisioned that embodiments of the working machine may comprise cover means (not shown), such as a lid, that is adapted to cover at least a portion of the dump body 30 and which cover means can be moved in order to obtain the open load receiving area 31 to thereby arrive at the open load receiving area 14. Generally, the open load receiving area 31 may be an area that is directly accessible from the environment surrounding the working machine 1. For instance, the open load receiving area 31 may be an area that is directly accessible from the above of the dump body 30.

[0089] The working machine does not have a driver seat, but is intended to be autonomously and/or remotely driven. The machine further comprises a first side 3 and a second side 2 arranged opposite to the first side 3, the second side 2 being a load dumping side 2. The first side 3 may also be referred to as an opposite side 3. The opposite side 3 may be used as a front end side when the machine is driven in the direction that puts the opposite side 3 first. However, the working machine 1 may be drivable in any direction, i.e. it is bidirectional. Further, the dump body 30 comprise a load dumping end portion 32 arranged on the working machines load dumping side 2, and an opposite end portion 33 arranged on the working machines opposite side 3.

[0090] Further, still refereeing to FIG. 1 the working machine 1 comprise a working machine frame 20 to which a pair of propulsion axles 10 are mounted. The working machine frame 20 further supports the dump body 30, and thereby carries the load of anything contained in the dump body 30 as well as the weight from the dump body itself. The propulsion axles 10 are equipped with a propulsion hub 14 (not shown in FIG. 1) for driving propulsion means 60. In the figures the propulsion means 60 are illustrated as wheels, however, they may also be crawlers.

[0091] Further, an electrical engine 70 is installed onto the propulsion axle 10 being coupled to a drive shaft (not shown). The electrical engine 70 is mounted onto a front side of the propulsion axle's 10 elongated main body, said front side facing away from a centre of the working machine 1. The working machine may comprise one electrical engine 70 on each machine axle 10.

[0092] Further, the working machine 1 may comprise a tilting arrangement 40, such as a tilting arrangement comprising one or more tilting actuators 41, such as hydraulic actuators, for tilting the dump body 30 of the working machine 1. The tilting arrangement 40 is in one end attached to the frame 20 and in the other end to the dump body 30. Preferably, the tilting arrangement 40 comprise two tilting actuators 41 arranged at different sides of the dump body to ensure a stable tilting (as shown in FIG. 3).

[0093] FIG. 1 finally disclose an electrical control arrangement 75, arranged to the frame of the working machine 1. The electrical control arrangement 75 may comprise (as illustrated in FIG. 2) a power source 76 e.g. a battery arrangement, for supporting the electrical engine(s) 70 and any other components with power. Further, the electrical control arrangement 75 may comprise a control unit 77 for controlling the working machine. The control unit 77 may be capable of receiving a remote control signal to enable the working machine to be remotely controlled. Such a signal may be received from an external transmission unit (not shown). It may further be capable of communicating any information to or from the working machine from or to a remote server (not shown). Such information may comprise usage data, service information, battery status, load, weight, capacity utilization or any other relevant information.

[0094] The load receiving area circumference 34 may form a closed loop that fully encloses a continuously open load receiving area 31. However, some embodiments of the working machine 1 may comprise one or more internal partitioning walls partitioning the open load receiving area 31 into two or more compartments (not shown).

[0095] The propulsion axle arrangement 10 also comprises a cover arrangement 90 for covering the electrical engine, wherein the cover arrangement comprises a first (inner) cover 91 and a second cover 92 being arranged on the outside of the first cover.

[0096] Turning to FIG. 2, being the side view of the same embodiment of the vehicle, the working machine frame 20 is clearly illustrated as being coupled the propulsions means 60, i.e. the wheels, (via the propulsion axle, which is not seen in this view). Further, the illustration shows that the dump body 30 rests on the working machine frame 20. However, in the illustrated embodiment it is not in contact with the frame 20 during its whole length, but rather at the load dumping side 2 at an attachment means 21 being a pivotal arrangement allowing the dump body 30 to pivot relative the frame 20. The dump body 30 further rests on the frame 20 at a guiding plate portion 22, which will be further described in relation to FIG. 3. Further, the tilting arrangement 40, with one of the side's tilting actuators 41 is clearly sown in FIG. 2. The tilting actuator 41 is in one end attached to the frame 20 and in the other end to the dump body 30. Further, the tilting actuator may be extended so that the dump body's opposite end portion 33 is elevated. Preferably, the tilting arrangement 40 comprise two tilting actuators 41 arranged at different sides of the dump body to ensure a stable tilting, and to spread the load on two actuators enabling a lower dimension of the tilting actuators for the same load.

[0097] As is also clearly shown in FIGS. 1 and 2, the working machine 1 extends in at least a longitudinal direction L, a vertical direction V and a transversal direction T. The longitudinal direction L is parallel to an intended direction of travel of the working machine 1. Further the transversal direction T is perpendicular to each one of the vertical direction V and the longitudinal direction L. That is, the transversal direction T is parallel to the general extension of the propulsion axles 10. These directions are intended to be interpreted relative the working machine, and should not be interpreted as being dependent of the vehicle's orientation.

[0098] Further, the electrical control arrangement 75 is illustrated in the side view of FIG. 2. The placement of the electrical control arrangement 75 should only be considered to be an example. It is preferably arranged between the two working machine axles 10 and coupled to the frame 20, but the exact placement may be chosen in so that it is functionally placed in the environment which the working machine is to be used. Having the electrical control arrangement 75 on the outside of the frame, so that it is accessible from the side of the vehicle gives that advantage that both maintenance is facilitated and that any transceiving unit in the control arrangement, sending and/or receiving information may obtain a better signal and/or range. However, it would be possible to place the electrical control arrangement 75 transversally central on the working machine, i.e. under the dump body 30.

[0099] The dump body 30 of the working machine may further be designed so that the working machine 1 can assume a position relative to a second working machine of the same type, in which position the dump bodies at least partly overlap in at least the longitudinal or transversal direction. Generally, overlap of the dump bodies may be obtained on any side of the working machines 1. For instance, the overlap may be obtained along the longitudinal sides or the transversal sides of the working machines 1. For example, the above overlap may be at least 2%, preferably at least 5%, more preferred at least 8% of the load receiving length of the open load receiving area 31 in said longitudinal direction L.

[0100] Further, in FIG. 3 the working machine is shown in a front view, in one embodiment of the invention. In the front view, the working machine 1 is illustrated from one of the transversal sides, and more specifically from the side called the opposite side 3, being the side opposite of the load dumping side 2. The frame 20 is coupled to the propulsion axle 10, via the suspension arrangement 50 allowing the frame 20 to move relative the propulsion axle 10 in the vertical plane. Further, the propulsion axle comprises two opposing end portions 12, 13 each having a propulsion hub (not shown) coupled the propulsions means 60, i.e. the wheels in this embodiment. Further, the dump body 30 rests on the working machine frame 20 at a guiding plate portion 22. The dump body 30 comprise a load supporting end portion 35, which cooperates with a guiding plate portion 22 and works as a guiding means for guiding the dump body towards a transversally centred position during a pivotal downward movement of the dump body relative the frame. The formation of these guiding plate portions and load supporting end portions may be formed with an angle to a horizontal plane, i.e. with a vertical inclination. Further, the tilting arrangement 40 is clearly shown having two tilting actuators 41 arranged on each longitudinal side of the dump body. The tilting actuators 41 are attached to the dump body 30 at its top portion in a rotational coupling 42. Further, the tilting actuator may be extended so that the dump body's opposite end portion 33 is inclined. Finally, FIG. 3 illustrates that the propulsion axle is equipped with an electrical engine 70 being drivably coupled to a drive shaft inside the propulsion axle (thus not shown) and mounted onto the illustrated front side 16 of the elongated main body 11, said front side 16 facing away from a centre of the working machine 1 in the transversal direction. This is further illustrated in the subsequent figures. In FIGS. 1-3 the electrical engine 70 and gear box 80 are hidden by the engine cover 90, and is thus only noted with a dashed line in FIG. 3.

[0101] In FIG. 5 and FIG. 6 a working machine 201 according to one embodiment is shown. In FIG. 5 a side view showing the first and second propulsion axle suspension arrangements 250, 250′ of the working machine 201 is shown, and in FIG. 6 a side view of the working machine 201 of FIG. 5 in a load dumping sate is shown. The configuration shown in FIGS. 5 and 6 is applicable to the working machine 1 shown in FIGS. 1-3. Moreover, as the working machine 201 in FIGS. 5 and 6 comprises the same or similar features and components as the working machine 1 in FIGS. 1-3, similar reference numerals are used for corresponding features, but with the addition of “200”.

[0102] In FIG. 5, a working machine having a first side 203 and a second side 202 arranged opposite to the first side 203 is shown, the second side 202 being a load dumping side 202. The working machine 201 comprises a dump body 230 for receiving a load, a working machine frame 220 for supporting the dump body 230, and at least one tilting actuator 241 connecting the working machine frame 220 and the dump body 230 such that, in a load dumping state, the dump body 230 is tiltable by means of the at least one tilting actuator 241 in order to discharge the load from the dump body 230 (as shown in FIG. 6).

[0103] The working machine 201 further comprises a first propulsion axle 210 arranged in the first side 203 of the working machine 201, and a second propulsion axle 210′ arranged in the second side 202 of the working machine 201. A first propulsion axle suspension arrangement 250 is arranged between the first propulsion axle 210 and the working machine frame 220; and a second propulsion axle 250′ suspension arrangement arranged between the second propulsion axle 210′ and the working machine frame 220.

[0104] As shown in FIG. 5, the second propulsion axle suspension arrangement 250′ comprises at least one projection arm 251′ extending from the second propulsion axle 210′ towards the working machine frame 220, and a suspension cushion 252′ arranged between the projection arm 251′ and the working machine frame 220. The suspension cushion 252′ is configured to suspensionally take up a load, up to a threshold load.

[0105] Turning now to FIG. 6 showing the same working machine 201 as in FIG. 5, but in a state where the tilting actuator 241 has tilted the dump body 230 into the load dumping state.

[0106] The dump body 230 comprises a first end portion 233 and a second end portion 232 arranged on the opposite side to the first end portion 233, the second end portion 232 being a load dumping end portion 232 which is pivotally arranged to the working machine frame 220 (e.g. by means of an attachment means). The tilting actuator 241 is connected to the dump body 230 in such a way that in the load dumping state, the first end portion 233 of the dump body 230 is lifted.

[0107] As clearly shown in FIG. 6, the suspension cushion 252′ is configured in such a way that the load from the working machine frame 220 to the second propulsion axle suspension arrangement 250′ exceeds the threshold load, when the working machine 201 is in its load dumping state. Thus, in FIG. 6, the load from the working machine frame 220 is taken up mainly by the at least one projection arm 251′. Hereby, the connection between the working machine frame 220 and the second propulsion axle suspension arrangement 250′ is made stiff.

[0108] Stated differently, the second propulsion axle suspension arrangement 250′ has a second propulsion axle damping characteristics, wherein in the load dumping state the second propulsion axle damping characteristics is adapted to make the second propulsion axle suspension arrangement 250′ stiff. In other words, in the load dumping state, the second propulsion axle damping characteristics is zero or close to zero.

[0109] As also shown in FIG. 6, the first propulsion axle suspension arrangement 250 is different from the second propulsion axle suspension arrangement 250′. Thus, the damping characteristic of the first propulsion axle suspension arrangement is different from the second propulsion axle damping characteristics. Typically, the first propulsion axle suspension arrangement 250 has a greater suspension ability compared to the second propulsion axle suspension arrangement 250′.

[0110] Turning back to FIG. 5, the working machine 201 further comprises a first linkarm arrangement 215 pivotably connecting the first propulsion axle 210 with the working machine frame 220 such that the roll axis RA1 of the first propulsion axle 210 relative the working machine frame 220 is comprised in the first linkarm arrangement 215. Correspondingly, the working machine 201 further comprises a second linkarm arrangement 215′ pivotably connecting the second propulsion axle 210′ with the working machine frame 220 such that the roll axis RA2 of the second propulsion axle 210′ relative the working machine frame 220 is comprised in the second linkarm arrangement 215′. As shown in FIG. 5, the first and second linkarm arrangements 215, 215′ are positioned above the first and second propulsion axles 210, 210′, respectively. Thus, the respective roll axis RA1, RA2 is positioned above the first and second propulsion axles 210, 210′, respectively. As also shown in FIG. 5, the two roll axis RA1, RA2 coincides, and the coinciding roll axis is positioned horizontally above the respective upper ends of the first and second propulsion hubs.

[0111] Now the position of the respective roll axis RA1, RA2 above the respective first and second propulsion axles 210, 210′, will be described in more detail. The position of the roll axis RA1 of the first propulsion axle 210 may be described as follows: a ratio of a first parameter A defined as the shortest distance between the center of the first propulsion axle 210 and the roll axis RA1 of the first propulsion axle 210, and a second parameter B defined as the shortest distance between the center of the first propulsion axle 210 and the ground G is between 0.35 and 1.0, preferably between 0.55 and 0.75, and more preferably between 0.65 and 0.75. That is A/B is between 0.35 and 1.0, preferably between 0.55 and 0.75, and more preferably between 0.65 and 0.75. Defined differently, the shortest distance between the center of the first propulsion axle 210 and the roll axis RA1 of the first propulsion axle 210 (i.e. parameter A) is between 200 mm and 500 mm, preferably between 300 mm and 400 mm.

[0112] Correspondingly, the position of the roll axis RA2 of the second propulsion axle 210′ may be described as follows: a ratio of a third parameter C defined as the shortest distance between the center of the second propulsion axle 210′ and the roll axis RA2 of the second propulsion axle 210′, and a fourth parameter D defined as the shortest distance between the center of the second propulsion axle 210′ and the ground G is between 0.35 and 1.0, preferably between 0.55 and 0.75, and more preferably between 0.65 and 0.75. That is C/D is between 0.35 and 1.0, preferably between 0.55 and 0.75, and more preferably between 0.65 and 0.75. Defined differently, the shortest distance between the center of the second propulsion axle 210′ and the roll axis RA2 of the second propulsion axle 210′ (i.e. parameter C) is between 200 mm and 500 mm, preferably between 300 mm and 400 mm.

[0113] As only a side view of the working machine 201 is shown in FIGS. 5 and 6, only one projection arm 251′ and only on suspension cushion 252′ etc are shown. However, according to one embodiment, the opposite side of the working machine 201 to what is shown in FIGS. 5 and 6, comprises the same, or identical, components as shown in FIGS. 5 and 6 (e.g. a respective projection arm, suspension cushion etc.)

[0114] Turning now to FIG. 4 showing a perspective view of a portion of the working machine 1, 201. The configuration shown in FIG. 4 s applicable to the working machine 1 shown in FIGS. 1-3, and/or the working machine 201 shown in FIGS. 5-6. Thus, corresponding features and components in the working machine 1, 201 of FIGS. 1-3 and 5-6 are given similar reference numerals.

[0115] In FIG. 4, a working machine frame 120 and one propulsion axle 110 having an elongated main body 111 comprising a first end portion 112, a second end portion 113 and a center portion 111C arranged between said first and second end portions 112, 113, is shown. Each one of the first second end portions 112, 113 is here equipped with a respective propulsion hub 114 for driving a working machine propulsion means such as e.g. a wheel. The elongated main body 111 has a main body length MBL extending from said first end portion 112 to said second end portion 113.

[0116] Also shown in FIG. 4 is a propulsion axle suspension arrangement 150 arranged between said working machine frame 120 and said propulsion axle 110. The propulsion axle suspension arrangement 150 of FIG. 4 may for example be used as the first propulsion axle suspension arrangement 250 in FIGS. 5 and 6. Note than in FIG. 4, a portion of the working machine frame 120 covering the suspension arrangement 150 from above is removed for clarity reasons. The propulsion axle suspension arrangement 150 comprises a first suspension device 151 and a second suspension device 152 arranged on opposite sides of a center C of the elongated main body 111, each one of said first and second suspension devices 151, 152 is holding a suspension fluid (not shown).

[0117] As can be seen in FIG. 4, the first and second suspension devices 151, 152 are arranged in the center portion 111C of the elongated main body 111. In FIG. 4, the center portion is centrally arranged on said elongated main body 111, and is delimited to be closer to, but not higher than, 50% of the main body length MBL.

[0118] As also shown in FIG. 4, the propulsion axle suspension arrangement 150 further comprises a fluid communication path 153 configured to enable suspension fluid communication between said first suspension device 151 and said second suspension device 152. Thus, fluid may be exchanged by the first and second suspension device 151, 152 via said fluid communication path 153. In FIG. 4, the fluid communication path 153 is passively unregulated. In other words, according to such embodiments, there are no vents or valves regulating the flow of fluid through said fluid communication path 153.

[0119] Preferably, the propulsion axle suspension arrangement 150 of FIG. 4 is at least partly pneumatically driven. Thus, in such embodiments said first suspension device 151 is a first air bellow 151, and said second suspension device 152 is a second air bellow 152.

[0120] In FIG. 4, a linkarm arrangement 115 is pivotably connecting said propulsion axle 110 with said working machine frame 120. The linkarm arrangement 115 comprises two linkarms 115A, 115B, and a propulsion axle connection hub 119, each one of said two linkarms 115A, 115B has a respective propulsion axle end portion connected to the propulsion axle connection hub 119, and a respective frame end portion connected to said working machine frame 120. The two linkarms 115A, 115B is in

[0121] FIG. 4 forming a V-shaped link. Hereby, the linkarm arrangement prevents the propulsion axle to be pivoted in an undesired direction.

[0122] The roll axis RA of the propulsion axle relative the working machine frame is comprised in said linkarm arrangement 115. As the linkarm arrangement 115 is positioned above said center portion 111C of said elongated main body 111, the roll axis RA (and roll center) of the propulsion axle 110 is positioned above said center portion 111C of said elongated main body 111. In FIG. 4, the roll axis RA (and roll center), as well as at least a part of the linkarm arrangement 115, such as the propulsion axle connection hub 119, is centrally positioned between said first and said second suspension devices 151, 152.

[0123] The positioned of the roll axis RA above the propulsion axle 110 can be defined differently. For example, the roll axis may be defined as being positioned above the respective upper ends 114A of the first and second propulsion hubs 114.

[0124] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.