Hydraulically steered transport vehicle, preferably with variable width and track width Description
The invention relates to a hydraulically steered transport vehicle, in particu- lar with variable width and track width, which has a chassis with at least two steering axles, wherein the chassis comprises two chassis portions, which each carry a row of running gears which are arranged one behind the other — each with at least one wheel rotation arrangement which can preferably be adjusted transversely relative to a vertical longitudinal centre plane of the transport vehicle, wherein at a transverse side of the transport vehicle a cou- pling apparatus with a pivotable coupling element is arranged, via which the transport vehicle can be coupled to a towing or pushing vehicle which moves — the transport vehicle.
DE 10 2012 024 247 B4 of the applicant describes a generic transport vehi- cle showing the preamble of Claim 1, with variable width and track width, which comprises a chassis with at least one steering axle.
The chassis com- prises two chassis parts which each carry a row of wheel rotation arrange- ments arranged one behind the other and which are adjustable transversely to a vertical longitudinal centre plane of the transport vehicle.
The wheel rota- tion arrangements of each chassis portion are connected by longitudinal tie rods.
Between the two rows of wheel rotation arrangements, only a single longitudinally adjustable transverse tie rod is arranged which connects two wheel rotation arrangements of the or one of the steering axles and the length of which is adjustable by a dimension corresponding to the dimension of the enlargement or reduction of the width and track width.
The transverse tie rod connects two steering levers, which are each articulated between two adjacent wheel rotation arrangements on one of the two chassis portions.
For adjusting the width and the track width of the transport vehicle known from the previously mentioned publication it is necessary to configure the trans-
verse tie rod so as to be longitudinally adjustable and, with each change of the width of the known vehicle, to adapt the length thereof.
From DE 20 2013 011 633 Ul claiming the priority of the aforementioned patent it is known, further, to use a drawbar with the transport vehicle de- scribed above, which is coupled to the chassis of the transport vehicle.
For this purpose, the drawbar comprises a coupling part which can be rigidly connected to a coupling element of the chassis.
This coupling part has two elements, which with respect to one another can be pivoted about a vertical — pivot axis, and four hydraulic cylinders, which are arranged on both sides of the longitudinal centre plane of the transport vehicle in pairs between the aforementioned elements.
The first element of these two aforementioned elements is pivotable with respect to a drawbar part of the drawbar about an axis which is parallel to the ground.
The second of the two aforementioned elements comprises a vertical plate, which can be brought to lie against the front face of the coupling element of the chassis and which can be coupled to the coupling element by screw connection.
The hydraulic cylinders each comprise a piston rod articulated on the first element and a cylinder tube articulated on the second element.
After the coupling, the hydraulic cylin- — ders are hydraulically connected to a hydraulic steering circuit of steering axles of the transport vehicle, in order to also ensure in this way a desired turning angle of the drawbar between the two aforementioned elements.
From US 4,221,398 A, a transport vehicle in the form of a drawbar trailer and of a lowbed trailer with multiple steering axles is known, the width and track width of which can be enlarged or reduced when required, in that two chassis portions, which each carry a row of wheel rotation arrangements, are moved apart or together transversely to the travelling direction or to a verti- cal longitudinal centre plane of the transport vehicle.
There, the wheel rota- tion arrangements of each steering axle are steered independently of one another by means of separate steering cylinders, which are arranged in each of the two chassis portions.
Thus, however, an excessive quantity of steering cylinders for the steering are required on the one hand and on the other hand it cannot be ensured that during the steering, the steering angle of the two wheel rotation arrangements of each steering axle and thus the turning an- gles of the associated wheels or wheel pairs are identical. For steering the two wheel rotation arrangements of the two chassis portions, two control cylinders are provided, the piston-side end of which is arranged in each case on the corresponding chassis portion and the ring-side end of which on a cross member pivotably connecting the two chassis portions. A pivot movement of the drawbar thus causes a cylinder of one of the two con- trol cylinders to be extended and the other cylinder retracted. The two con- trol cylinders are each connected to corresponding steering cylinders via hydraulic lines. A piston-side end of each of the two steering cylinders is articulated on the corresponding chassis portion and a ring-side end of these steering cylinders is each connected to a first end of a steering lever, where- in each of these two steering levers, via its second end, is connected to the corresponding wheel rotation arrangement. A first hydraulic line of the con- trol cylinder on the left in the travelling direction leads from the piston-side outlet of this cylinder to a piston-side inlet of the steering cylinder on the — right in the travelling direction. In a corresponding manner, a piston-side outlet of the right control cylinder is connected to a piston-side inlet of the left steering cylinder. A further hydraulic line leads from the ring-side outlet of the left steering cylinder to the ring-side inlet of the right steering cylin-
der. The known transport vehicle, apart from the steering axle described above, additionally comprises a central steering axle and a rear steering axle each with a wheel rotation arrangement. The steering lever of each chassis portion of the front steering axle is in each case connected via a longitudinal tie rod to a first end of a steering lever of the central steering axle and the respectively second ends of these steering levers are coupled via a mechani- cal connection to the corresponding wheel rotation arrangement. A third longitudinal tie rod in each case leads from the respectively second of these two steering levers to a first end of the two levers of the steering axle, which in turn are mechanically connected via corresponding tie rods to the wheel rotation arrangements of the rear steering axle.
A second end in each case of the two steering levers of the rear steering axle is connected to a piston rod of further steering cylinders, the respectively other end of which is connect- ed to a rear cross member.
A further hydraulic line leads from the ring-side outlet of the left control cylinder to the ring-side inlet of the right rear steer- ing cylinder and in a corresponding manner a ring-side outlet of the front right control cylinder is connected to a ring-side inlet of the left rear steering cylinder.
A further hydraulic line connects the piston-side outlets of these two steering cylinders.
Disadvantageous with this known steering is that with the measures described in the aforementioned publication, only one steering circuit can be formed which can also generate only a low steering force.
It is therefore the object of the present invention to further develop a transport vehicle of the type mentioned at the outset in such a manner that with a simple configuration of the transport vehicle according to the inven- tion a steering with at least two steering circuits that are separate from one another with a higher steering force materialises.
This object is achieved through the transport vehicle according to the inven- tion in that the coupling apparatus has at least four control cylinders, where- in at least two control cylinders are connected with their ring-side end via piston rods at a first side of the pivotable coupling element and with their piston-side end to the coupling apparatus and at least two control cylinders with their ring-side end via piston rods to a second side of the pivotable coupling element and with their piston-side end to the coupling apparatus, that the first chassis and the second chassis each have a steering cylinder, wherein a first steering cylinder is articulated on a first wheel rotation ar-
rangement and a second steering cylinder in each case on a second wheel rotation arrangement in such a manner that in each case a piston-side end of the corresponding steering cylinder is connected at the chassis and a ring-
side end, via a corresponding piston rod, engages on the steering element of the corresponding wheel rotation arrangement, and that in each case a pis- ton-side connection opening of a control cylinder is connected to a piston- side connection opening of the steering cylinder assigned to this control cyl- 5 inder and a ring-side connection opening of this steering cylinder to a ring- side connection opening of this control cylinder via corresponding hydraulic lines.
The measures according to the invention have the advantage that a steering device for a transport vehicle with at least two active steering circuits is thereby created, which is also characterised in that an increased steering force is achieved in a simple manner.
The measures according to the inven- tion bring about that the piston-side outlets of the control cylinders are al- ways connected to the piston-side inlets of the corresponding steering cylin- ders; the steering of the active chassis thus takes place via the piston surface of the control cylinders and the steering cylinders.
Thus, the maximum hy- draulic and thus also mechanical steering force to be applied is advanta- geously achieved.
Here it is advantageous that the annular surfaces of the control cylinders and the annular surfaces of the steering cylinders are con- nected, which results in a stabilisation and synchronisation of the respective steering circuit.
A further advantage is that through the measures according to the invention a two-circuit steering is formed, which is characterised by an increased steering security: if for example the piston-side hydraulic con- nection between a steering cylinder and a control cylinder is interrupted, the steering unit continues to be maintained through the ring-side hydraulic con- nection.
Jackknifing of the transport vehicle through such a defect is thus effectively counteracted.
Thus, the transport vehicle according to the inven- tion can (according to the legal reguirements applicable in Germany at this time) be driven with a speed of up to 80 km/h.
A further advantage is that the coupling apparatus does not have to be directly mounted to the transport vehicle and be mechanically connected to the steering moving the chassis of this transport vehicle.
Through the described hydraulic control of the steer-
ing, adapters or longitudinal members for example can be advantageously coupled-in between the coupling apparatus and the chassis of the transport vehicle according to the invention without integrated steering and bridged by means of suitable hydraulic lines in order to reach the steering hydraulics of — the transport vehicle.
A further advantage of the measures according to the invention is that the steering device according to the invention is suitable in an advantageous manner for transport vehicles with fixed and in particular for transport vehicles with variable width.
An advantageous further development of the invention provides that at least one control cylinder of the steering of the transport vehicle according to the invention arranged on a first side of the chassis is hydraulically connected to a steering cylinder arranged on the same side of the chassis.
A further advantageous further development of the invention provides that the transport vehicle according to the invention is variable in its width and/or its track width.
According to an advantageous further development of the invention, this is achieved in that the two chassis portions can be dis- placed in the transverse direction relative to one another.
Further advantageous further developments of the invention are the subject matter of the subclaims.
Further details and advantages of the invention can be taken from the exem-
plary embodiment, which is described in the following by way of the fig- ures.
There:
Figure 1 shows a perspective representation of an exemplary em- bodiment of a transport vehicle,
Figure 2 shows a plan view of the exemplary embodiment of Fig-
ure 1,
Figure 3 shows a plan view of the front part of the transport vehi- cle of Figures 1 and 2 without transport surface in a first position of a drawbar,
Figure 4 shows a plan view of the front part of the transport vehi- cle of Figures 1 and 2 without transport surface in a sec- ond position of the drawbar, Figure 5 shows a perspective view of a drawbar coupling element, Figure 6 shows a plan view of the drawbar coupling element of Figure 5, Figure 7 shows a front view of the drawbar coupling element of Figure 5, Figure 8 shows a lateral view of the drawbar coupling element, Figures 9 and 10 show a schematic representation of a first variant of the two steering circuits of the transport vehicle, Figure 11 shows a schematic representation of a second variant of the two steering circuits of the transport vehicle, and
Figure 12 shows a schematic representation of the steering ar- rangement with a widened transport vehicle.
In Figures 1 to 4, an exemplary embodiment of a transport vehicle generally designated 1, which has two vehicle modules 2a and 2b which are mechani- cally coupled to one another, is illustrated.
Each of the two vehicle modules 2a, 2b comprises a number of chassis 10, wherein at least two and as — ac-
tive — chassis 10a, 10a' and 10b, 10b' are formed.
To the person skilled in the art it is evident from the following description that the steering discussed in the following is not limited to the configuration of the transport vehicle 1 with two vehicle modules 2a and 2b that are mechanically coupled to one another, which is shown in Figures 1 and 2. It is rather also possible to pro- vide more than two vehicle modules 2a, 2b or — as shown in Figures 3 and 4 — only a single vehicle module 2a.
It is only required that the overall transport vehicle 1 has at least two actively steered chassis 10a, 10a' and 10b, 10b', wherein it is not required that the actively steered chassis 10a, 10a', 10b, 10b' are arranged in the same vehicle module 2a, 2b.
In the de- scribed exemplary embodiment, it is exemplarily assumed that the first chas- sis 10a and 10a' of the first vehicle module 2a are the or one of the front axle lines and the second actively steered chassis 10b, 10b' the or one of the rear axle lines of the first vehicle module 2a.
Obviously it is also possible that the actively steered chassis 10b, 10b' is one of the axle lines of the second vehicle module 2b, for example the or one of the rear axle lines of the sec- ond vehicle module 2b.
Each of the two vehicle modules 2a, 2b is preferentially adjustable in its — width and thus track width, wherein it should also be noted here in turn that this adjustability of at least one of the two vehicle modules 2a, 2b is advan- tageous, but not mandatorily reguired.
In the following it is assumed that the vehicle modules 2a, 2b have a variable width and track width.
To the person skilled in the art it is easily evident which changes the said person has to perform when this advantage should not be realised, i.e. when one or more vehicle modules 2a, 2b are configured to be non-variable with respect to their width and track width.
For this purpose it is provided that a chassis 3 of one or two vehicle modules 2a, 2b comprises a first and a second chassis portion 4a and 4b which in a manner known per se are variable with respect to their spacing, so that through a suitable displacement movement in a direction extending trans-
versely to the vehicle longitudinal direction the spacing of the two chassis portions 4a, 4b relative to one another can be changed.
This can take place for example through cross members, as described in DE 10 2012 024 247 B4, or through a scissor connection, as explained in DE 10 2014 009 036 B4 for example.
In the described exemplary embodiment it is provided that be- tween the two chassis portions 4a, 4b an intermediate member 5 of suitable width is replaceably inserted.
This intermediate member 5 also has the ad- vantage that it reinforces the chassis 3 and thus ensures a substantially greater stiffness of same.
Thus it is possible in an advantageous manner to transport with the described transport vehicle 1 greater payloads than is the case with a vehicle not having such a structure.
On a front transverse side of the chassis 3 of the vehicle module 2a a cou- pling apparatus 20 — here a drawbar coupling apparatus — with a steering element, here with a drawbar 21, is provided, which will still be explained in detail in the following.
A drive device 7, which is likewise known and is thus not explained in any more detail, is coupled to a rear transverse side of the second vehicle module 2b.
For the sake of a clear representation, Figures 3 and 4 now show the first vehicle module 2a, the second vehicle module 2b is constructed accordingly.
From Figures 3 and 4 it is evident that the two active chassis 10a, 10a' and 10b and 10b' as well as all further chassis 10 are also configured so as to be — passively — steerable.
Each chassis 10, 10a, 10a’, 10b, 10b' comprises a wheel rotation arrangement 11a, 11a' and 11b, 11b' in each case, wherein the first wheel rotation arrangements 11a, 11b are rotatably arranged in the first chassis portion 4a and the second wheel rotation arrangements 11a’, 11b' in the second chassis portion 4b.
The configuration of such wheel rotation ar- rangements 11a—11b' is known and need therefore not be described in more — detail again.
Each wheel rotation arrangement 11a, 11b and 1la', 11b' has in each case a steering element 12a and 12b respectively preferentially config- ured as steering lever, wherein the steering elements 12a and the steering elements 12b of the first and of the second chassis portion 4a and 4b respec- tively are each connected to one another through longitudinal tie rods 13a and 13b respectively.
Such a design is described in DE 10 2012 024 247 B4 and therefore does not likewise have to be explained in detail.
In order to now convert a pivot movement of the drawbar 21 into a pivot and thus steering movement of the wheel rotation arrangements 1la-11b', it is provided in the described exemplary embodiment that — as described in the following — the drawbar 21 pressurizes control cylinders 30a-30d of the coupling apparatus 20, and these control cylinders 30a—30d are connected to steering cylinders 40a—40d articulated on the chassis portions 4a, 4b via hy- draulic lines shown in Figures 9 to 11 and still described in more detail fur- ther down below.
The control cylinders 30a-30d are still explained in the following by way of the description of the coupling apparatus 20. As is evi- dent from Figures 3 and 4, the first steering cylinder 40a articulated at the piston-side end on the first chassis portion 4a engages at the ring-side with a first side of a first steering element 14a of a steering unit 14, here embodied as steering plate, which is connected with the steering element 12a, here configured as steering lever, of the wheel rotation arrangement 11a of the — first chassis 10a via a longitudinal tie rod 13a and to the steering element 12a of the wheel rotation arrangement 11a situated adjacently via a further longitudinal tie rod 13a.
In a corresponding manner, the steering cylinder 40b likewise articulated with its piston-side end on the second chassis por- tion 4b engages on a second side of the steering element 14a of the steering — unit 14 and via a longitudinal tie rod 13b on the steering element 12b of the chassis 10a’. In a corresponding manner, the third and fourth steering cylin- ders 40c and 40d engage with their ring-side ends on a respective side of a steering element 14b, here configured as steering plate, of a further steering unit 14' on the steering elements 12a and 12b of the wheel rotation arrange- ments 11a and 11b respectively of the second chassis 10b, 10b'.
These steering cylinders 40a—40d are now controlled by the control cylin-
ders 30a—30d of the coupling apparatus 20, which is shown in Figures 5 to 8.
The coupling apparatus 20 comprises a crossbar 23, which can be fastened to the chassis 3 via two coupling elements 24a and 24b.
Further, a coupling apparatus 25 that is known per se and therefore not described again in more detail is provided, to which the drawbar 21 can be fastened and pivoted along a joint 26. The first control cylinder 30a is articulated on the crossbar
23 on the piston side and with its piston rod 31a engages on the coupling apparatus 25. In a corresponding manner, the second control cylinder 30b in
— turn is articulated on the crossbar 23 with its piston-side end and its piston rod 31b is connected to the coupling apparatus 25 in an articulated manner.
The further control cylinders 30c and 30d in turn act with their piston-side ends on the crossbar 24 and their piston rods 31c and 31d are articulated on the coupling apparatus 25. Each control cylinder 30a-30d comprises a pis-
— ton-side connection opening 32a—32d and a ring-side connection opening 33a—33d, to which the hydraulic lines shown in Figures 9 to 11 are connect-
ed, which extend to the steering cylinders 40a—40d as described in the fol- lowing: in Figure 9, a first variant is shown, which is characterised in that the chassis 10a, 10a' of the first axle line and the further chassis 10 coupled
— to these via longitudinal tie rods 13a, 13b and the chassis 10b, 10b' as well as the chassis 10 coupled to these chassis 10b, 10b' via the second longitudi-
nal tie rods 13a', 13b' are articulated in the opposite directions of rotation -
as evident from Figure 10. The piston-side connection opening 32a of the first control cylinder 30a is connected via a hydraulic line 35a to a piston-
— side connection opening 42a steering cylinder 40a.
In a corresponding man- ner, the piston-side connection opening 32b of the second control cylinder
30b is connected via a hydraulic line 35b to a piston-side connection open-
ing 42b of the steering cylinder 40b.
The ring-side connection opening 33a and 33b respectively of the first and of the second control cylinder 30a and
30b respectively is connected to a ring-side connection opening 43a and 43b respectively of the steering cylinder 40a and 40b respectively via a hydraulic line 36a and 36b respectively.
In a corresponding manner, the piston-side connection openings 32c and 32d of the control cylinders 30c and 30d are connected via hydraulic lines 35c, 35d to piston-side connection openings 42c, 42d of the steering cylinders 40c and 40d of the chassis 10b and 10b' respectively.
The ring-side connection openings 33c and 33d respectively of the control cylinders 30c and 30d respectively are connected via hydraulic lines 36c and 36d respectively to the ring-side connection openings 43c, 43d of the steering cylinders 40c, 40d.
When the drawbar 21 — as shown in Figures 3 and 4 — is now articulated from its central, neutral position (see Figure 3) into its, seen in the travelling direction, left position (see Figure 4), the piston rods 31a and 31c of the con- trol cylinders 30a and 30c are retracted, so that a hydraulic medium flowing in the hydraulic lines 35a and 35c respectively exits from the piston-side connection openings 32a and 32c respectively and in each case flows via a corresponding hydraulic line 35a and 35c respectively to the piston-side connection openings 42a and 42c respectively of the steering cylinders 40a and 40c respectively.
This causes the piston rods 41 of the steering cylinders 40a and 40c respectively to be extended so that the wheel rotation arrange- ment 11a of the chassis 10a and thus the wheel rotation arrangements 11a' of — the chassis 10a' of second chassis component 4b — as is evident from Figures 4 and 10 — are rotated in the anticlockwise direction.
At the same time, hy- draulic medium flows via the ring-side connection openings 33a and 33c of the steering cylinders 40a and 40c via corresponding hydraulic lines back to the ring-side connection openings 33a and 33c respectively of the first and of the third control cylinder 30a and 30c respectively.
The piston rods 41 of the steering cylinders 40b and 40d — as is evident from a comparison of Figures 9 and 10 — are retracted.
The wheel rotation ar- rangements 11b and 11b' of the chassis 10b and 10b' thus pivot in the clock- — wise direction, i.e. opposite to the direction of rotation of the chassis 10a and 10a".
Since — as described above — a first group of chassis 10 is connected via lon- gitudinal tie rods 13a, 13a' to the steering elements of the chassis 10a, 10a’, the chassis 10 of this first group of chassis 10 also pivot in the same direc- tion with the pivot and thus steering movement of the chassis 10a, 10a’. This applies in a corresponding manner to the chassis 10 to be assigned to a sec- ond group of chassis 10, which are connected via longitudinal tie rods 13b, 13b' to the chassis 10b, 10b'. When the drawbar 21 is now pivoted in its opposite direction, i.e. seen in the travelling direction to the right, the flow relationships are correspondingly reversed.
This is clearly evident to the person skilled in the art and need therefore not be described in more detail.
With the described transport vehicle 1 it is thus provided that for each pair of interacting control cylinders and steering cylinders 30a, 40a and 30b, 40b respectively of a first steering circuit respectively 30c, 40c and 30d, 40d respectively of a second steering circuit are formed.
This has the advantage that compared with the transport vehicles known from the prior art increased steering forces can thus be achieved in a simple manner.
In Figure 11, a second variant of the configuration of the two steering cir- cuits of the transport vehicle 1 is shown.
As is evident from this figure, it is achieved by the configuration of the steering circuits described in the fol- lowing that the chassis 10 of the first group of chassis, i.e. those chassis 10 which are connected via longitudinal tie rods 13a, 13b to the actively steered chassis 10a, 10a', and the second group of chassis 10, i.e. those chassis 10, which are connected to the actively steered chassis 10b, 10b' via longitudinal tie rods 13a’, 13b', are articulated in a same direction upon a pivot movement of the drawbar 21.
As is evident from Figure 11, the routing of the hydraulic lines of the first steering circuit corresponds to that of the first variant shown in Figures 9 and 10. In the second variant according to Figure 12, the line routing of the hydraulic lines of the second steering circuit is then "mirrored". Now, the hydraulic lines emanating from the control cylinders 30c, 30d are not routed to the steering cylinders 40c and 40d respectively arranged on the same side of the transport vehicle 1. The hydraulic lines of the control cylinder 30c are routed to the corresponding openings of the steering cylinder 40d and the hydraulic lines of the control cylinder 30c to the steering cylinder 40c.
Figure 12 now shows a particularly advantageous configuration of the steer- ing elements 14a and 14b respectively of the first and the second steering unit 14 and 14' respectively, configured as steering plates, which makes pos- sible a simple adjustment of the width of the transport vehicle 1. It is pro- vided that the steering elements 14a and 14b are not embodied in one part — as in the schematic representations of Figures 9 to 11 — but that the steering elements 14a and 14b respectively each comprise two separate steering ele- ment parts 14a’, 14a" and 14b', 14b" respectively, which are each connected by a transverse tie rod 15. Through a simple change of the length of the transverse tie rods 15, the width of the transport vehicle 1 and consequently the track width can be easily adjusted.
In the description described above, it is assumed that the transport vehicle 1 is variable in its width and its track width in that the two chassis portions 4a and 4b can be displaced in the transverse direction relative to one another.
However, it is evident from the above description to the person skilled in the art that the described steering cannot only be employed in transport vehicles 1 with variable width.
In summary it should be noted that through the described measures a steer- ing device for a transport vehicle 1 that is suitable in particular for transport — vehicles with variable width, but not limited to these, having at least two active steering circuits is created, which is characterised in that in a simple manner an increased steering force is achieved.
In an advantageous manner this is easily achieved in that for each active steering circuit, i.e. both for the chassis 10a, 10a' and also for the chassis 10b, 10b' a separate hydraulic cir- cuit is formed in each case.
This is achieved in that a pair of interacting con- trol cylinders 30a and 30b as well as 30c and 30d only pressurize a pair of interacting steering cylinders 40a and 40b as well as 40c and 40d with hy- draulic fluid.