U.S. patent application number 14/713302 was filed with the patent office on 2017-07-13 for trackless tugger train and method for steering a trackless tugger train.
This patent application is currently assigned to Hamburg Innovation GmbH. The applicant listed for this patent is Hamburg Innovation GmbH, Helmut-Schmidt-Universitat. Invention is credited to Rainer Bruns, Konstantin Krivenkov, Stephan Ulrich.
Application Number | 20170197657 14/713302 |
Document ID | / |
Family ID | 51520302 |
Filed Date | 2017-07-13 |
United States Patent
Application |
20170197657 |
Kind Code |
A9 |
Bruns; Rainer ; et
al. |
July 13, 2017 |
TRACKLESS TUGGER TRAIN AND METHOD FOR STEERING A TRACKLESS TUGGER
TRAIN
Abstract
The subject matter of the invention is a trackless tugger train
(100) having at least one transportation module (10) and at least
two axle modules (11), wherein each transportation module (11) is
arranged between two axle modules (11), wherein each axle module
(11) has a wheel axle (12) and a steering device for steering the
wheel axle (12), wherein the steering devices of the axle module
(11) are embodied in each case in such a way that each steering
device steers the axle module (11) which is assigned to it,
independently of a steering device of another axle module (11).
Inventors: |
Bruns; Rainer; (Hamburg,
DE) ; Ulrich; Stephan; (Hamburg, DE) ;
Krivenkov; Konstantin; (Hamburg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Helmut-Schmidt-Universitat
Hamburg Innovation GmbH |
Hamburg
Hamburg |
|
DE
DE |
|
|
Assignee: |
Hamburg Innovation GmbH
Hamburg
DE
Helmut-Schmidt-Universitat
Hamburg
DE
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20150367885 A1 |
December 24, 2015 |
|
|
Family ID: |
51520302 |
Appl. No.: |
14/713302 |
Filed: |
May 15, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B62D 13/005 20130101;
B62D 12/02 20130101; B62D 53/00 20130101; B62D 13/02 20130101; F16H
1/2854 20130101; B62D 53/005 20130101; B62D 5/0421 20130101; B62D
63/08 20130101; B62D 13/00 20130101 |
International
Class: |
B62D 13/02 20060101
B62D013/02; B62D 63/08 20060101 B62D063/08; F16H 1/28 20060101
F16H001/28; B62D 12/02 20060101 B62D012/02; B62D 53/00 20060101
B62D053/00; B62D 5/04 20060101 B62D005/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2014 |
DE |
102014106928.5 |
Oct 13, 2014 |
DE |
202104104858.8 |
Claims
1. Trackless tugger train (100) having at least one transportation
module (10) and at least two axle modules (11), wherein each
transportation module (10) is arranged between two axle modules
(11), wherein each axle module (11) has a wheel axle (12) and a
steering device for steering the wheel axle (12), wherein each
steering device of an axle module (11) is embodied in each case in
such a way that the steering device steers the axle module (11)
which is assigned to it, independently of a steering device of
another axle module (11).
2. Trackless tugger train (100) according to claim 1, characterized
in that the axle modules (11) each have a first cantilever arm (14)
and a second cantilever arm (15), wherein the first cantilever arm
(14) and the second cantilever arm (15) are connected to the wheel
axle (12) via an articulated connection (16).
3. Trackless tugger train (100) according to claim 2, characterized
in that the articulated connection (16) has at least one vertical
pivoting joint (33, 33a, 33b), wherein the vertical pivoting joint
(33, 33b, 33) has a rotational axis (34) which is embodied
vertically with respect to the longitudinal extent of the
cantilever arms (14, 15).
4. Trackless tugger train (100) according to claim 3, characterized
in that the articulated connection (16) has precisely one vertical
pivoting joint (33), wherein the first cantilever arm (14) and the
second cantilever arm (15) are connected to the one vertical
pivoting joint (33).
5. Trackless tugger train (100) according to claim 3, characterized
in that the articulated connection (16) has a first vertical
pivoting joint (33a) and a second vertical pivoting joint (33b),
wherein the first cantilever arm (14) is connected to the wheel
axle (12) via the first vertical pivoting joint (33a), and wherein
the second cantilever arm (15) is connected to the wheel axle (12)
via the second vertical pivoting joint (33b).
6. Trackless tugger train (100) according to one of claims 2 to 5,
characterized in that the articulated connection (16) has a
horizontal pivoting joint (51), wherein the horizontal pivoting
joint (51) has a rotational axis (54) which extends transversely
with respect to the direction of travel (17) of the tugger train
(100) at least in the case of straight-ahead travel of the tugger
train (100).
7. Trackless tugger train (100) according to one of claims 2 to 6,
characterized in that the steering device is embodied in such a way
that the steering device steers the wheel axle (12) into an
angle-bisecting position between the first cantilever arm (14) and
the second cantilever arm (15).
8. Trackless tugger train (100) according to one of claims 2 to 7,
characterized in that the steering device has at least two
connecting rods (26, 28), wherein a first connecting rod (26) is
connected by a first end to the first cantilever arm (14) and by a
second end to the wheel axle (12), and wherein a second connecting
rod (28) is connected by a first end to the second cantilever arm
(15) and by a second end to the wheel axle (12), wherein the
connecting rods (26, 28) are each guided in a displaceable fashion
in a linear guide (30, 31) by their first end or their second
end.
9. Trackless tugger train (100) according to one of claims 1 to 7,
characterized in that the steering device is embodied in the form
of a gear unit.
10. Trackless tugger train (100) according to claim 9,
characterized in that the gear unit has a first gear wheel (36)
connected to the first cantilever arm (14), a second gear wheel
(37) connected to the second cantilever arm (15), and at least a
third gear wheel (38) connected to the wheel axle (12), wherein the
first gear wheel (36) and the second gear wheel (37) are connected
in a rotationally movable fashion by means of the at least one
third gear wheel (38).
11. Trackless tugger train (100) according to one of claims 1 to 7,
characterized in that the steering device is embodied in the form
of a spring-damper system.
12. Trackless tugger train (100) according to claim 11,
characterized in that the spring-damper system has a first spring
element (42) connected to the first cantilever arm (14) and to the
wheel axle (12), a second spring element (43) connected to the
second cantilever arm (15) and to the wheel axle (12), and at least
one damper element (44, 45, 46, 47).
13. Trackless tugger train (100) according to claim 12,
characterized in that the at least one damper element (44) is
connected to the wheel axle (12) and to the first cantilever arm
(14) or to the second cantilever arm (15).
14. Trackless tugger train (100) according to claim 12,
characterized in that the spring-damper system has three damper
elements (45, 46, 47) which are each connected by a first end to
the wheel axle (12) and by a second end to an attachment frame (48)
connected to the articulated connection (16), wherein a first
damper element (45) and a second damper element (46) are arranged
inclined at an angle<90.degree. with respect to the longitudinal
extent of the wheel axle (12) and are connected to a first side of
the wheel axle (12), and wherein a third damper element (47) is
arranged vertically with respect to the longitudinal extent of the
wheel axle (12) and is connected to a second side of the wheel axle
(12) lying opposite the first side.
15. Trackless tugger train (100) according to one of claims 1 to 7,
characterized in that the steering device has a motor-powered drive
which is controlled by means of an electronic control unit.
16. Trackless tugger train (100) according to one of claims 2 to
14, characterized in that a last axle module (11) when viewed in
the direction of travel (17) of the tugger train (100) is connected
by its first cantilever arm (14) to a transportation module (10)
and by its second cantilever arm (15) to a bogie frame (19) having
at least one wheel (21).
17. Trackless tugger train (100) according to claim 16,
characterized in that a Bissell bogie (50) is arranged between the
last axle module (11) when viewed in the direction of travel (17)
of the tugger train (100) and the bogie frame (19).
18. Trackless tugger train (100) according to claim 17,
characterized in that the Bissell bogie (50) has a connecting rod
(60) which is connected by a first end to the wheel axle (12) of
the last axle module (11) when viewed in the direction of travel
(17), and by a second end, lying opposite the first end, to a wheel
axle (20) of the bogie frame (19).
19. Trackless tugger train (100) according to claim 17,
characterized in that the Bissell bogie (50) has a first connecting
rod (58), a second connecting rod (59) and a guide element (56)
which is mounted in a displaceably movable fashion on the second
cantilever arm (15) of the last axle module (11) when viewed in the
direction of travel (17), wherein the first connecting rod (58) is
connected to the guide element (56) and to the wheel axle (12) of
the last axle module (11) when viewed in the direction of travel
(17), and wherein the second connecting rod (59) is connected to
the guide element (56) and to a wheel axle (20) of the bogie frame
(19).
20. Trackless tugger train (100) according to one of claims 1 to
19, characterized in that at least two transportation modules (10)
are provided in the form of U-shaped supporting frames, wherein the
at least two transportation modules (10) have at their upper ends
at least one outwardly directed supporting arm (61, 62) each with a
coupling element (63, 64), wherein supporting arms (61, 62),
arranged opposite one another, of transportation modules (10) which
are arranged adjacent to one another are coupled to one another in
an articulated fashion by means of the coupling elements (63,
64).
21. Trackless tugger train (100) according to claim 20,
characterized in that the coupling elements (63, 64) of supporting
arms (61, 62) which are arranged opposite one another are connected
to a full-floating axle (65) arranged on the articulated connection
(16).
22. Method for steering a trackless tugger train (100) embodied
according to one of claims 1 to 20, in which method a steering
angle of the steering device of an axle module (11) is adapted to a
trajectory of the trackless tugger train (100).
23. Method according to claim 22, characterized in that in the case
of a travel motion of the trackless tugger train (100) the
adaptation of the steering angle is carried out continuously, at
intervals which follow one another within a short period of
time.
24. Method according to claim 22 or 23, characterized in that in
order to adapt the steering angle an axle centre point of the axle
module (11) to be steered and an axle centre point of the axle
module (11) arranged directly in front thereof, when viewed in the
direction of travel (17) of the trackless tugger train (100) are
determined.
Description
FIELD OF INVENTION
[0001] The present invention relates to a trackless tugger train.
In addition, the invention relates to a method for steering a
trackless tugger train.
BACKGROUND OF THE INVENTION
[0002] Trackless tugger trains can be used, in particular, as
industrial trucks for transportation within a company's premises,
for example. A tugger train usually has at least one transportation
module, preferably two or more transportation modules which are
arranged one behind the other and which can be embodied in such a
way that they can transport loads or goods, in particular
horizontally. In addition, the tugger train generally has a towing
vehicle which is harnessed in front of the first transportation
module when viewed in the direction of travel, in order to tow the
transportation modules and therefore move in a desired direction.
An important objective when configuring a tugger train is that the
transportation modules follow the towing vehicle with the greatest
possible directional stability. Small directional deviations of the
transportation modules, or even none at all if possible, permit
narrow travel lanes of the tugger train, with the result that the
tugger train can be moved safely even on small traffic areas.
Furthermore, the directional stability reduces the risk of
collision accidents, since transportation modules which do not move
in the track of the towing vehicle can quickly collide in bends
with persons or objects located at the edge of the travel lane.
[0003] Various configurations of the running gear units of the
transportation modules are known from the prior art. For example,
the transportation modules can have two main wheels which are
arranged on a wheel axle in a non-pivotable fashion. In addition to
the main wheels, further support rollers, which are embodied as
trailing rollers, can preferably be arranged at the corners of the
transportation module in order to safely support the transportation
module. These support rollers can orient themselves automatically
and therefore usually do not influence the trailing behaviour and
the directional stability significantly. The running gear unit of
these two-wheel or single axle transportation modules is of simple
design and can therefore be manufactured cost-effectively. Since no
device is required to steer the wheels, the running gear unit has a
low level of complexity, as a result of which it requires little
maintenance and is operationally reliable. The disadvantage of this
running gear unit which is arranged directly on the transportation
module is, however, that the axle with the two main wheels has to
be located approximately in the centre of the transportation module
in order to be able to achieve a good trailing behaviour and
therefore a high level of conventional stability of the
transportation module. However, this considerably restricts the
possibilities in terms of loading the transportation modules with
rollable transportation frames. In particular, unless additional
technical aids are used, transportation modules with such running
gear units cannot be loaded on both sides with relatively large
transportation frames whose footprints dimensions correspond
approximately to the width of the transportation modules.
[0004] In order to be able to permit the transportation modules to
be loaded and unloaded on both sides with transportation frames or
other rollable cargo carriers, four-wheeled transportation module
running gear units have been developed for a tugger train in which
in each case two wheels are arranged on one axle. These wheels are
mounted in such a way that they can be pivoted about a vertical
axis using a mechanical or hydraulic steering device. A trackless
tugger train with such a running gear unit is known, for example,
from DE 10 2008 060 801 B3. Steering angles of the wheels are
changed here by the steering device as a function of the angle
between the trailer drawbar and the trailer longitudinal axis. The
individual steering devices are coupled to one another here, for
example, via a linkage, with the result that the steering angles of
the front wheels correspond in value to the steering angles of the
rear wheels. It is disadvantageous here that the steering movement
of the front axle wheels has to be transmitted to the rear wheels
by reversing the direction. This is difficult, in particular, when
the transportation modules are to be loaded and unloaded on both
sides with rollable transportation frames. For this purpose, an
embodiment of the transportation modules is used which is referred
to as a U-frame and whose supporting frame has, when viewed from
the side, the shape of a gantry which is open at the bottom. The
pillars of this gantry are supported here by the two wheel axles.
The transmission of the steering lock from the front axle to the
rear axle is particularly costly here, since the movement has to be
transferred over relatively large distances and experiences a
plurality of directional deflections. The technical expenditure on
implementation for such a tugger train is therefore very high, as a
result of which both the manufacturing costs and the maintenance
requirements are high.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is therefore to make
available a trackless tugger train which is distinguished by good
loadability, good trailing behaviour with low directional
stability, and by ease of manufacture with a low level of technical
complexity. In addition, an object of the present invention is to
make available a method for steering a trackless tugger train, by
means of which particularly good dimensional stability of the
trackless tugger train can be achieved.
[0006] This object is achieved with the features of the independent
claims. Advantageous developments of the invention are specified in
the dependent claims.
[0007] According to the invention, a trackless tugger train is
provided which has at least one transportation module and at least
two axle modules, wherein each transportation module is arranged
between two axle modules. Each axle module has a wheel axle and a
steering device for steering the wheel axle. Each steering device
of an axle module is embodied in each case in such a way that the
steering device steers the axle module which is assigned to it,
independently of a steering device of another axle module.
[0008] In the tugger train according to the invention, both the
wheel axle and the steering device are arranged on the axle module
and not on the transportation module. The tugger train is therefore
constructed from an articulated-belt-like system of alternatingly
arranged axle modules and transportation modules and is thus not
constructed from transportation modules or trailers which are
coupled to one another in an arrangement one behind the other. The
tugger train can have a transportation module, preferably a
plurality of transportation modules which are arranged one behind
the other, wherein the transportation modules can have load-pick-up
devices by means of which the transportation modules can pick up
loads or goods to be transported. The axle modules support the
weight of the transportation modules and of the loads or goods to
be transported on the ground via the wheel axle to which preferably
two wheels are attached. Each axle module has, in addition to the
wheel axle, a steering device which orients the wheel axle in such
a way that the directional deviations during the customary travel
maneuvers are as small as possible or tend towards zero. The
steering devices of the individual axle modules are not coupled or
connected to one another but instead the steering device of each
axle module operates independently of the steering devices of the
other axles modules. The steering devices of the axle modules are
therefore not operatively connected to one another in the tugger
train according to the invention. As a result of the fact that the
steering devices of the axle modules are not coupled to one another
or are not operatively connected, there is also no connection
provided, for example in the form of a linkage, between the
individual steering devices or axle modules, which otherwise would
have to be guided by means of the transportation modules and
therefore can impede the loadability of the transportation modules.
By contrast, the transportation modules of the tugger train
according to the invention are not restricted in their loadability,
with the result that the transportation modules can be loaded from
both sides with rollable transportation frames without difficulty.
In addition, the technical complexity during the manufacture of
such a tugger train according to the invention is also reduced,
since there is no need to form or produce a connection, which is
costly in terms of construction and which is to be mounted, between
the individual axle modules or the steering devices of the axle
modules. As a result of the fact that according to the invention
each steering device of an axle module operates or acts
independently of other steering devices of other axle modules, it
is also not necessary to transmit information and/or energy from
the towing vehicle to the axle modules or from one axle module to
another.
[0009] The axle modules have, in addition to the wheel axle and the
steering device, in each case preferably a first cantilever arm and
a second cantilever arm, wherein the first cantilever arm and the
second cantilever arm are preferably connected, in particular
indirectly or directly, to the wheel axle via an articulated
connection. The two cantilever arms, which can also be embodied as
supporting frames, serve as connecting means between the axle
modules and the transportation modules or the towing vehicle. By
means of the first cantilever arm, for example, a transportation
module can be attached, with its rear side directed opposite to the
direction of travel, to the axle module. In the case of the axle
module which is arranged as the first one in the tugger train, the
towing vehicle can be attached with its rear side by means of the
first cantilever arm. By means of the second cantilever arm, for
example a transportation module can be attached, with its front
side directed in the direction of travel, to the axle module. The
cantilever arms are preferably embodied from a rigid material. In
an attached state of the transportation modules or of the towing
vehicle to, in each case, a cantilever arm, the connection between
the cantilever arms and the transportation modules or the towing
vehicle is embodied in a rigid fashion, with the result that a
movement between a cantilever arm and a transportation module or a
towing vehicle is prevented. As result of this rigid connection,
all the operating forces and torques which occur can be transmitted
between the respective axle module and the respective
transportation module. In order to be able to exchange the
transportation modules and/or to be able to make the tugger train
shorter or longer, the cantilever arms are preferably configured in
such a way that the transportation modules or the towing vehicle
can easily be released from the cantilever arms and also attached
again. As a result, the tugger train can be adapted to changing
operating conditions and requirements without a large amount of
expenditure.
[0010] In order, in particular, to permit cornering of the tugger
train, the first cantilever arm and the second cantilever arm are
preferably connected to the wheel axle by means of an articulated
connection. By means of this articulated connection, the first
cantilever arm can be rotated relative to the second cantilever
arm, and vice versa, with the result that the transportation
modules which are attached to the cantilever arms can follow the
cornering of the towing vehicle. The cantilever arms are connected
to the respective wheel axle of an axle module via the articulated
connection, with the result that a defined rotational movement
between, in each case, a cantilever arm and the wheel axle can be
made possible.
[0011] The articulated connection preferably has a least one
vertical pivoting joint, wherein the vertical pivoting joint
preferably has a rotational axis which is embodied vertically with
respect to the longitudinal extent of the cantilever arms. The one
vertical pivoting joint or the plurality of vertical pivoting
joints, which are preferably embodied in the form of a shaft,
permit a relative movement of the two cantilever arms of an axle
module with respect one another. As a result of the rotational axis
of the vertical pivoting joints, a lateral rotational movement of
the two cantilever arms of an axle module vertically with respect
to the longitudinal extent of the cantilever arms can be made
possible, with the result that the tugger train can travel through
bends. The vertical pivoting joint or vertical pivoting joints are
preferably embodied in a rigid fashion with a high degree of
strength so that the vertical pivoting joints can transmit tensile
forces, the weight forces of the transportation modules and of the
loads to be transported and tilting moments which can arise in the
case of cornering as a result of the centrifugal forces and when
the centre of gravity is off-centre.
[0012] The articulated connection can have, for example, precisely
one vertical pivoting joint, wherein the first cantilever arm and
the second cantilever arm are then preferably connected to the one
vertical pivoting joint. If a single vertical pivoting joint to
which both cantilever arms of an axle module are attached is
provided, the steering movement of the wheel axle can be
simplified, since the wheel axle can then be steered without moving
the transportation modules which are connected to the corresponding
axle module.
[0013] Alternatively it is, however, also possible for the two
cantilever arms of an axle module not to be connected directly to
the wheel axle via a common vertical pivoting joint, but instead
for the articulated connection to have a first vertical pivoting
joint and a second vertical pivoting joint, wherein the first
cantilever arm is preferably connected to the wheel axle via the
first vertical pivoting joint, and wherein the second cantilever
arm is connected to the wheel axle via the second vertical pivoting
joint. The two vertical pivoting joints can be arranged here, for
example, on a plate which is fixedly connected to the wheel axle,
and can be connected to the wheel axle and also to one another via
this plate.
[0014] Furthermore, it is possible for the articulated connection
to have a horizontal pivoting joint, wherein the horizontal
pivoting joint preferably has a rotational axis which extends
transversely with respect to the direction of travel of the
trackless tugger train, in particular in the case of straight-ahead
travel of the tugger train. The horizontal pivoting joint can be
arranged in the first cantilever arm itself or between the first
cantilever arm and the wheel axle or in the second cantilever arm
itself or between the second cantilever arm and the wheel axle. The
rotational axis of the horizontal pivoting joint can permit a
downward and upward rotational movement of the cantilever arms
about the horizontal pivoting joint, as result of which a travel
motion of the tugger train for example over an uneven piece of
ground such as, for example, travelling on a ramp with a gradient,
can be compensated.
[0015] In order to be able to achieve an optimum steering movement
of the transportation modules with very high directional stability,
the steering device is preferably embodied in such a way that the
steering device steers the wheel axle into an angle-bisecting
position between the first cantilever arm and the second cantilever
arm. Accordingly, there is preferably provision that a first, front
steering angle between the first cantilever arm and the wheel axle
and that a second, rear steering angle between the second
cantilever arm and the wheel axle are adjusted to an essentially
equally large position by the steering device. The steering device
is therefore preferably embodied in such a way that it can
correspondingly adjust or orient the wheel axle in such a way that
the wheel axle can be placed, even during cornering, in a position
in which the first, front steering angle is of the same size as the
second, rear steering angle. The steering device can be composed of
a mechanical, hydraulic, pneumatic, electromagnetic or
electric-motor-powered system for steering the wheel axle.
[0016] For example, the steering device can have at least two
connecting rods, preferably embodied in a rigid fashion, wherein a
first connecting rod can be connected by a first end to the first
cantilever arm and by a second end to the wheel axle, and wherein a
second connecting rod can be connected by a first end to the second
cantilever arm and by a second end to the wheel axle, wherein the
connecting rods can each be guided in a displaceable fashion in a
linear guide by their first end or their second end. As a result of
the arrangement of these at least two connecting rods which are
guided in a linear fashion on one side, a steering device with
simple mechanical kinematics can be formed, in which the first,
front steering angle and the second, rear steering angle are always
of the same size and therefore the wheel axle is always oriented in
the direction of the angle-bisector between the two cantilever
arms. With such a steering device, the two steering angles are
forcibly set as a function of the angle, also known as the bend
angle, between the first cantilever arm in the second cantilever
arm. Such a steering device is distinguished by a simple design, as
a result of which the manufacturing costs and also the expenditure
on maintenance are low. In addition, such a steering device is also
distinguished by low susceptibility to faults. In order to be able
to increase the rigidity of such a steering device, it may also be
preferred for said steering device to have four connecting rods,
wherein a third connecting rod is connected, like the first
connecting rod, by a first end to the first cantilever arm and by a
second end to the wheel axle, and wherein a fourth connecting rod
is connected, like the second connecting rod, by a second end to
the wheel axle, wherein the third and the fourth connecting rods
can also each be guided in a displaceable fashion in a linear
guide, by their first end or their second end.
[0017] A steering device with simple mechanical kinematics in which
the first, front steering angle and the second, rear steering angle
are always of the same size, and therefore the wheel axle is always
oriented in the direction of the angle-bisector between the two
cantilever arms, can also be embodied in such a way that the
steering device is embodied in the form of a gear unit. The gear
unit permits a 1:1 transmission ratio, by means of which the wheel
axle can be brought into an angle-bisecting position between the
first cantilever arm and the second cantilever arm. By means of the
gear unit, a rotational movement of the first cantilever arm, for
example in the clockwise direction, can be transformed into a
rotational movement of the second cantilever arm in the
anti-clockwise direction, and vice versa.
[0018] The gear unit can have a first gear wheel connected to the
first cantilever arm, a second gear wheel connected to the second
cantilever arm, and at least a third gear wheel connected to the
wheel axle, wherein the first gear wheel and the second gear wheel
can be connected in a rotationally movable fashion by means of the
at least one third gear wheel. The gear wheels can be embodied
here, for example, in the form of bevel gears which are arranged so
as to engage one in the other.
[0019] In addition it is also possible for the steering device to
be embodied in the form of a spring-damper system. By means of a
spring-damper system, particularly good directional stability of
the transportation modules can be obtained in the case of both
steady-state and dynamic driving maneuvers. In addition, a
spring-damper system is distinguished by a simple mechanical
design.
[0020] The spring-damper system preferably has a first spring
element connected to the first cantilever arm and the wheel axle, a
second spring element connected to the second cantilever arm and
the wheel axle, and at least one damper element. The spring
elements can be embodied, in particular, as linear spring elements
or as torsion or torsional springs. The spring elements are
preferably embodied in such a way that they can produce a resulting
torque which the wheel axle orients in the direction of the
angle-bisector between the first cantilever arm and the second
cantilever arm.
[0021] In order to be able to achieve a high level of directional
stability even in the case of dynamic driving maneuvers, such as
entering a bend or exiting a bend, at least one damper element is
preferably provided in addition to the two spring elements. The
damper element can be connected to the wheel axle and to the first
cantilever arm or to the second cantilever arm. The damper element
is preferably embodied in such a way that it can generate a force
or a torque which depends on the value and the direction of the
speed at which the length or the angle of the damper element can be
changed. The force or the torque of the damper element always
preferably acts counter to the direction of movement here. As a
result, delayed steering of the wheel axle is made possible. In the
case of dynamic driving maneuvers it is advantageous if the first,
front steering angle rotates more quickly than the second, rear
steering angle. This can be achieved in that the first cantilever
arm rotates more quickly with respect to the wheel axle than the
second cantilever arm with respect to the wheel axle, wherein the
speed of the rotational movement of the second cantilever arm with
respect to the wheel axle can be damped or reduced by means of the
damper element.
[0022] There is preferably provision that the damper element is
embodied in such a way that the effect of the damper element can be
changed as a function of the velocity of the respective wheel axle,
as a result of which the influence of the velocity on the
directional stability can be reduced or even entirely eliminated.
The velocity of a wheel axle, i.e. the speed of the centre of the
wheel axle, can be determined from locally available movement
variables, for example the rotational speed of the wheels of the
wheel axle.
[0023] In order to be able to adapt the steering behaviour of the
tugger train to the respective operating conditions, the damper
element can also be embodied in an adjustable fashion. This permits
a user to optimize the directional stability or the trailing
behaviour of the transportation modules of the tugger train in the
case of cornering by adjusting the damper element.
[0024] In the case of a spring-damper system there is particularly
preferably provision that the spring-damper system has three damper
elements which are each connected by a first end to the wheel axle
and by a second end to an attachment frame connected to the
articulated connection, wherein a first damper element and a second
damper element are preferably arranged inclined at an angle of
<90.degree. with respect to the longitudinal extent of the wheel
axle and are connected to a first side of the wheel axle, and
wherein preferably a third damper element is arranged vertically,
preferably at an angle of 90.degree., with respect to the
longitudinal extent of the wheel axle, and is connected to a second
side of the wheel axle lying opposite the first side. As a result
of this embodiment of the spring-damper system, particularly good
directional stability can be achieved during cornering.
[0025] Furthermore, it is possible for the steering device to have
a motor-powered drive which can be controlled by means of an
electronic control unit. With such a steering device, the wheel
axle of an axle module can be steered using the motor-powered
drive, wherein the motor-powered drive, also referred to as a
motor-powered servo-drive, of each steering device of an axle
module can be controlled by the electronic control unit as a
function of the time profiles of the velocity and of the steering
angle of the towing vehicle or as a function of the time profiles
of the velocity and of the steering angle of the axle module
travelling directly ahead thereof. The steering devices of the
individual axle modules operate independently of one another, are,
as it were, autonomous, and are therefore not connected to one
another or not operatively connected to one another. The
motor-powered drive of a steering device preferably has a motor for
generating a mechanical actuating power and a gear unit for
adapting actuation travel and an actuation torque or an actuation
force. The motor-powered drive of the steering device can form a
type of steering angle-correction device. Open-loop or closed-loop
control of the motor-powered drive can be performed by the
electronic control unit in such a way that the axle centre point of
the axle module which is to be adjusted or steered follows as
precisely as possible the trajectory of the axle centre point of
the axle module arranged immediately ahead of the latter, when
viewed in the direction of travel of the tugger train. For this
purpose, the current position of the axle centre point of the axle
module which is to be adjusted or steered and the trajectory of the
axle centre point of the axle module which is arranged directly
ahead of the latter when viewed in the direction of travel of the
tugger train are determined. In order to determine the axle centre
points or the coordinates of the axle centre points, state
variables and/or movement variables such as the accelerations
and/or the speeds at two different points on the wheel axle of the
axle module, the rotational acceleration of the wheel axle about
its vertical axis which extends perpendicularly with respect to the
direction of travel of the tugger train, the rotational speeds of
the two wheels of an axle module, the wheel loads or wheel contact
forces and/or the angles between the wheel axle and the cantilever
arm, arranged ahead of or behind the latter, of the axle module can
be determined. These state variables and/or movement variables can
be measured locally at the corresponding axle module, with the
result that a data-transmitting connection between the individual
axle modules via lines or by radio is not necessary. However, it is
alternatively also possible that the determination of the state
variables and/or movement variables of the axle module which is to
be adjusted or steered can be carried out by communication with the
axle module which is arranged directly ahead of the latter when
viewed in the direction of travel of the tugger train. If the axle
centre points of the respective axle modules are determined, the
distance between the axle centre point of the axle module which is
to be adjusted or steered and the axle centre point of the axle
module which is arranged directly ahead of the latter when viewed
in the direction of travel of the tugger train can be obtained. If
the distance between the axle centre points is known, variables
which are required for the steering control of the wheel axle of
the axle module to be steered can be determined by means of this
data and by means of suitable algorithms, with the result that the
steering angle of the axle module which is to be adjusted or
steered can be changed in such a way that the axle centre point of
the axle module which is to be adjusted or steered is steered again
to the trajectory which is provided. A mathematical model of
movement dynamics of the entire tugger train can be stored in the
electronic control unit and can be used to calculate the optimum
steering angles of the individual wheel axles at any point in time.
The steering angles which are obtained in the process can be set,
for example, by means of a controlled electric-motor-powered
steering drive. For this purpose, the actual steering angles are
preferably measured continuously and the measured signals are fed
back to the controller of the steering device. As a result of the
fact that this process, and therefore the correction of the
steering angle of an axle module, preferably takes place
continuously, at short intervals, optimum directional stability or
optimum trailing behaviour of the tugger train can be achieved by
means of such as steering device without directional deviations on
the trajectory of the tugger train.
[0026] The steering device requires energy for the determination or
measurement of the state variables and/or movement variables, for
the electronic control unit and for the motor-powered drive. The
required energy can be made available, for example, by the towing
vehicle in an electrical, pneumatic or hydraulic form and can be
transmitted to the individual axle modules by means of electric
leads, such as cables. Alternatively it is also possible that the
required energy can be made available from the rotational movement
of the respective wheels of the axle modules, for example by using
an electric generator, with the result that the required energy is
generated at the respective axle module itself. So that energy can
be made available, at least temporarily, even when the tugger train
is stationary, in this embodiment each axle module preferably has
an energy accumulator.
[0027] A last axle module when viewed in the direction of travel of
the tugger train is connected by its first cantilever arm
preferably to a transportation module and by its second cantilever
arm preferably to a bogie frame having at least one wheel. The last
axle module when viewed in the direction of travel forms the
termination of the tugger train. Behind the last axle module when
viewed in the direction of travel, there is no further
transportation module arranged which could serve to orient the
wheel axle of the last axle module. In order to be able to
compensate this, a bogie frame is preferably arranged behind the
last axle module, which bogie frame is connected to the second
cantilever arm. The bogie frame which can have one wheel, or else
can also be embodied as a wheel axle with two wheels, is connected
to the second cantilever arm either so as to be rotatable about a
rotational axis in a vertical direction with respect to the
longitudinal extent of the second cantilever arm, like the wheel
axle of the last axle module with respect to the second cantilever
arm, or fixedly or rigidly.
[0028] In order to be able to ensure directional stability of the
entire tugger train during steady-state circular travel of the
tugger train, there is preferably provision that a Bissell bogie is
arranged between the last axle module when viewed in the direction
of travel of the tugger train and the bogie frame. The arrangement
of a Bissell bogie is advantageous, in particular, when the length
of the second cantilever arm of the last axle module, which is
arranged between the articulated connection of the last axle module
and the bogie frame, is greater than or smaller than half the
distance between two axle modules which are arranged one behind the
other and between which a transportation module is arranged.
[0029] The Bissell bogie can preferably have a connecting rod which
is connected by a first end to the wheel axle of the last axle
module and by a second end, lying opposite the first end, to a
wheel axle of the bogie frame.
[0030] Furthermore it is also possible that the Bissell bogie has a
first connecting rod, a second connecting rod and a guide element
which is mounted in a displaceably movable fashion on the second
cantilever arm of the last axle module when viewed in the direction
of travel, wherein the first connecting rod can be connected to the
guide element and to the wheel axle of the last axle module, and
wherein the second connecting rod can be connected to the guide
element and to a wheel axle of the bogie frame.
[0031] If the steering device has a motor-powered drive and an
electronic control unit, a bogie frame and a Bissell bogie are no
longer necessary.
[0032] Furthermore, at least two transportation modules can be
provided in the form of U-shaped supporting frames, wherein the at
least two transportation modules preferably have at their upper
ends at least one outwardly directed supporting arm each with a
coupling element, wherein supporting arms, arranged opposite one
another, of transportation modules which are arranged adjacent to
one another are preferably coupled to one another in an articulated
fashion by means of the coupling elements. The coupling elements of
supporting arms which are arranged opposite one another can be
connected to a full-floating axle arranged on the articulated
connection.
[0033] The object according to the invention is also achieved by
means of a method for steering a trackless tugger train which is
embodied and developed as described above and in which a steering
angle of the steering device of an axle module is adapted to a
trajectory of the tugger train. Particularly good directional
stability of the tugger train can be achieved over the length of
the tugger train by adapting the steering angle of the steering
device of each axle module of the tugger train, in which the
individual axle modules follow a trajectory of the tugger train as
precisely as possible. In this context, the steering angle for each
steering device is set independently of the steering angles of the
other steering devices of the other axle modules, with the result
that each steering device of the individual axle modules operates
autonomously with respect to the steering devices of the other axle
modules and can be readjusted according to a corresponding
calculation process. In order to set the steering angle, each
individual steering device preferably has a motor-powered drive and
an electronic control unit.
[0034] In order to increase the directional stability further,
there is preferably provision that during a travel motion of the
tugger train, the adaptation of steering angle is carried out
continuously, at intervals which follow one another within a short
period of time. In this context, the steering angle during a travel
motion of the tugger train is preferably determined again
repeatedly at defined time intervals which follow one another in
short succession, with the result that the steering angle of a
steering device of an axle module can be corrected continuously
during the entire travel motion of the tugger train, and
correspondingly adapted to the trajectory of the tugger train.
[0035] In order to adapt the steering angle, an axle centre point
of the axle module to be steered and an axle centre point of the
axle module arranged directly ahead thereof, when viewed in the
direction of travel of the tugger train, are preferably determined.
In order to determine the axle centre points or the coordinates of
the axle centre points, state variables and/or movement variables
such as the accelerations and/or the speeds at two different points
on the wheel axle of the axle module, the rotational acceleration
of the wheel axle about its vertical axis extending perpendicularly
with respect to the direction of travel of the tugger train, the
rotational speeds of the two wheels of an axle module, the wheel
loads or wheel contact forces and/or the angles between the wheel
axle and the cantilever arm of the axle module arranged ahead of or
behind said wheel axle can be determined. These state variables
and/or movement variables can be measured locally at the
corresponding axle module, with the result that a data-transmitting
connection between the individual axle modules via leads or by
radio is not necessary. However, it is alternatively also possible
for the state variables and/or movement variables of the axle
module which is to be adjusted or steered to be determined by
communication with the axle module which is arranged immediately
ahead thereof when viewed in the direction of travel of the tugger
train. If the axle centre points of the respective axle modules are
determined, the distance between the axle centre point of the axle
module which is to be adjusted or steered and the axle centre point
of the axle module which is arranged directly ahead thereof when
viewed in the direction of travel of the tugger train can be
obtained. If the distance between the axle centre points is known,
variables required for the steering control of the wheel axle of
the axle module to be steered can be determined by means of this
data and by means of suitable algorithms, with the result that the
steering angle of the axle module which is to be adjusted or
steered can be changed in such a way that the axle centre point of
the axle module which is to be adjusted or steered is steered again
to the trajectory which is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Further measures which improve the invention are presented
in more detail below together with the description of preferred
exemplary embodiments of the invention with reference to the
figures. In the drawings:
[0037] FIG. 1 shows a schematic illustration of a trackless tugger
train according to the invention,
[0038] FIG. 2 shows a schematic illustration of a detail of the
tugger train which is shown in FIG. 1 and which has three axle
modules and two transportation modules,
[0039] FIG. 3 shows a schematic illustration of an axle module of a
tugger train as shown in FIG. 1,
[0040] FIG. 4 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0041] FIG. 5 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0042] FIG. 6 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0043] FIG. 7 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0044] FIG. 8 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0045] FIG. 9 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0046] FIG. 10 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0047] FIG. 11 shows a schematic illustration of a last axle module
of a tugger train as shown in FIG. 1 and has a bogie frame arranged
behind it,
[0048] FIG. 12 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0049] FIG. 13 shows a further schematic illustration of an axle
module of a tugger train as shown in FIG. 1,
[0050] FIG. 14 shows a schematic illustration of geometry of
steady-state circular travel of a tugger train embodied according
to one possible embodiment,
[0051] FIG. 15 shows a schematic illustration of a connection of a
last axle module with a bogie frame in a tugger train as shown in
FIG. 14,
[0052] FIG. 16 shows a schematic illustration of geometry of
steady-state circular travel of a tugger train embodied according
to a further possible embodiment,
[0053] FIG. 17 shows a schematic illustration of a connection of a
last axle module with a bogie frame in a tugger train as shown in
FIG. 16,
[0054] FIG. 18 shows a schematic illustration of geometry of
steady-state circular travel of a tugger train embodied according
to a further possible embodiment,
[0055] FIG. 19 shows a schematic illustration of a connection of a
last axle module to a bogie frame in a tugger train as shown in
FIG. 18, and
[0056] FIG. 20 shows a schematic illustration of a detail of the
tugger train which is shown in FIG. 1 and has three axle modules
and two transportation modules according to a further
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0057] FIG. 1 is a schematic view of a trackless tugger train 100.
The tugger train 100 has a plurality of transportation modules 10,
here five, arranged one behind the other. Each transportation
module 10 is arranged between two axle modules 11.
[0058] The axle modules 11 each have a wheel axle 12 with two
wheels 13 arranged thereon. Furthermore, each axle module 11 has a
first cantilever arm 14 and a second cantilever arm 15, wherein the
cantilever arms 14, 15 are connected to one another approximately
centrally along the longitudinal extent of the wheel axle 12 via an
articulated connection 16, with the result that the cantilever arms
14, 15 can be rotated relative to one another.
[0059] In the case of an axle module 11 which is arranged between
two transportation modules 10, the first cantilever arm 14 is
connected to a front transportation module 10 when viewed in the
direction of travel 17, and the second cantilever arm 15 is
connected to a rear transportation module 10, when viewed in the
direction of travel 17. The first axle module 11, when viewed in
the direction of travel 17, and the last axle module 11, when
viewed in the direction of travel 17, are exceptions to this. In
the case of the first axle module 11 when viewed in the direction
of travel 17, the first cantilever arm 14 is connected to a towing
vehicle 18 which tows the tugger train 100. The second cantilever
arm 15 is connected to the first transportation module 10 of the
tugger train 100. In the case of the last axle module 11 when
viewed in the direction of travel 17, the first cantilever arm 14
is connected to the last transportation module 10 of the tugger
train 100. The second cantilever arm 15 of the last axle module 11
when viewed in the direction of travel 17 is connected to a bogie
frame 19 which, in the embodiment shown here, is formed by a wheel
axle 20 with two wheels 21, wherein the wheel axle 20 of the bogie
frame 19 has a shorter length than the wheel axles 12 of the axle
modules 11.
[0060] Each axle module 11 has, in addition to its wheel axle 12
and the two cantilever arms 14, 15, a steering device (not
illustrated in FIG. 1.). The steering device is shown in various
embodiments in FIGS. 4-10. The steering devices of the axle modules
11 are each embodied in such a way that each steering device steers
the axle module 11 which is assigned to it, independently of a
steering device of another axle module 11. The steering devices of
the individual axle modules 11 are not coupled or connected to one
another, but instead the steering device of each axle module 11
operates independently of the steering devices of the other axle
modules 11, with the result that the steering devices of the
individual axle modules 11 are not operatively connected to one
another.
[0061] FIG. 2 shows a detail of a tugger train 100 with two
transportation modules 10 which are arranged one behind the other
and which are each arranged between two axle modules 11. The
transportation modules 10 are each embodied in the form of U-shaped
supporting frames which can be loaded and unloaded with
transportation loads from both sides without any impediments. The
transportation modules 10 have for this purpose suitable devices
for picking up the loads. For example, in each case one or more
angular profiles 49 can be arranged as load pickup means at lower
ends of the transportation modules 10 which are directed towards
the underlying surface, as shown in FIG. 2.
[0062] Each transportation module 10 has two connecting elements
22, 23, wherein the front connecting element 22 when viewed in the
direction of travel 17 is rigidly connected to the second
cantilever arm 15 of an axle module 11 arranged ahead of the
transportation module 10, and wherein the rear connecting element
23 when viewed in the direction of travel 17 is rigidly connected
to the first cantilever arm 14 of an axle module 11 which is
arranged behind the translation module 10, with the result that no
rotational movement is possible between the cantilever arms 14, 15
and the connecting elements 22, 23, for example when the tugger
train 100 is cornering. In order to be able to release the
transportation modules 10 from the axle modules 11 again, the
connections of the connecting elements 22, 23 to a respective
cantilever arm 14, 15 are embodied in a releasable fashion. In
order to increase the stability, the connecting elements 22, 23 are
embodied in a wedge shape in the embodiment shown here.
[0063] In the embodiment of the transportation modules 10 in the
form of U-shaped supporting frames, very high forces act on the
transportation modules 10, since the entire tensile force is
transmitted by the towing vehicle 18 via each transportation module
10 with peak loads and torques. As a result, high bending torques
occur in the transportation modules 10 which are embodied in the
form of U-shaped supporting frames. In order to reduce the forces
and torques acting on the transportation modules 10, an alternative
embodiment to FIG. 2 is shown in FIG. 20.
[0064] FIG. 20 shows, like FIG. 2, a detail of a tugger train 100
with two transportation modules 10 which are arranged one behind
the other and which are each arranged between two axle modules 11.
On the transportation modules 10, in each case an outward directed
supporting arm 61, 62 is arranged at their upper ends. At the free
ends of the supporting arms 61, 62, in each case a coupling element
63, 64 is arranged, for example, in the form of a hinge. The two
supporting arms 61, 62, lying opposite one another, of
transportation modules which are arranged adjacent to one another
are coupled to one another in an articulated fashion via the
coupling elements 63, 64 in that the coupling elements 63, 64
engage one in the other, for example. The coupling elements 63, 64
are in turn connected to a full-floating axle 65 which is arranged
on the articulated connection 16. The full-floating axle 65 extends
perpendicularly with respect to the direction of travel 17 starting
from the articulated connection 16 and extending to the coupling
elements 63, 64. The full-floating axle 65 forms a rotational axis
between the transportation modules 10 which are arranged adjacent
to one another, concentrically with respect to the vertical axis of
the articulated connection 16. By means of the articulated
connection of the transportation modules 10 to one another at their
upper ends by means of the supporting arms 61, 62 of the coupling
elements 63, 64 and the full-floating axle 65, the forces acting on
the transportation modules 10 can be passed on directly to the
other transportation modules 10, while bypassing the steering
device of the axle modules 11, and can therefore be distributed
uniformly among all the transportation modules 10.
[0065] FIG. 3 shows a schematic illustration of an axle module 11,
with a wheel axle 12 on which two wheels 13 are arranged, and with
a first cantilever arm 14 and a second cantilever arm 15 connected
to the first cantilever arm 14 via an articulated connection 16.
The longitudinal axes 24, 25 of the two cantilever arms 14, 15
which are connected to the wheel axle 12 by the articulated
connection 16 form a bending angle .gamma. of the axle module 11.
In the case of straight-ahead travel of the tugger train 100, the
bending angle .gamma.=180.degree.. In the case of left-handed
cornering, the bending angle .gamma. is <180.degree., as is
shown in FIG. 3. And in the case of right-handed cornering, the
bending angle .gamma. is >180.degree..
[0066] The position of the wheel axle 12 divides the bending angle
.gamma. into a first, front steering angle .alpha..sub.v, which is
formed between the wheel axle 12 and the first cantilever arm 14 or
the longitudinal axis 24 of the first cantilever arm 14, and into a
second, rear steering angle .alpha..sub.h, which is formed between
the wheel axle 12 and the second cantilever arm 15 or the
longitudinal axis 25 of the second cantilever arm 15, with the
result the following is true:
.gamma.=.alpha..sub.v+.alpha..sub.h.
[0067] FIGS. 4 to 7 show embodiments of a steering device in which
the two steering angles .alpha..sub.v and .alpha..sub.h are always
of the same magnitude. The steering device is therefore embodied in
such a way that it steers the wheel axle 12 in such a way that the
wheel axle 12 is always oriented in the direction of the
angle-bisector of the bending angle .gamma., wherein the
angle-bisector is defined in such a way that in the angle-bisector
the steering angles .alpha..sub.v and .alpha..sub.h are of the same
magnitude.
[0068] FIGS. 4 and 5 show an embodiment of a steering device in
which the steering device is embodied in the form of a scissor
mechanism. The steering device is embodied in the embodiment shown
here from four connecting rods 26, 27, 28, 29, which are each
guided by one of their ends in a linear guide 30, 31. A first and a
third connecting rod 26, 28 are each connected by a first end to
the first cantilever arm 14 and by a second end to the wheel axle
12. A second and a fourth connecting rod 27, 29 are each connected
by a first end to the second cantilever arm 15 and by a second end
to the wheel axle 12. The attachment of the connecting rods 26, 27,
28, 29 to the cantilever arms 14, 15 is embodied in each case in a
positionally fixed fashion, with the result that the connecting
rods 26, 27, 28, 29 cannot be displaced along the cantilever arms
14, 15. However, the attachment of the connecting rods 26, 27, 28,
29 to the cantilever arms 14, 15 is embodied in an articulated
fashion, with the result that the connecting rods 26, 27, 28, 29
can be pivoted about the attachment point on the cantilever arms
14, 15, for example when the tugger train 100 is cornering. In
contrast, the connecting rods 26, 27, 28, 29 are guided in the
linear guide 30, 31 on the wheel axle 12 in a linear fashion, with
the result that the connecting rods 26, 27, 28, 29 can be displaced
along the longitudinal extent of the wheel axle 12.
[0069] The linear guides 30, 31 each extend to the right and left
when viewed from the centre of the wheel axle 12, wherein a first
linear guide 30 extends to the left of the articulated connection
16, when viewed in the direction of travel 17, in the direction of
the wheel 13, and a second linear guide 31 extends to the right of
the articulated connection 16, when viewed in the direction of
travel 17, in the direction of the wheel 13. The linear guides 30,
31 have, in the wheel axle 12, groove-shaped or slot-shaped
cut-outs 35, in each of which a sliding element 32 of the linear
guides 30, 31 is guided. On the sliding elements 32, in each case
two of the connecting rods 26, 27, 28, 29 are attached by means of
a pivoting joint connection, wherein the first and second
connecting rods 26, 28 are attached together on a sliding element
32 of the first linear guide 30 by means of a pivoting joint
connection, and wherein the third and fourth connecting rods 27, 29
are attached together on a sliding element 32 of the second linear
guide 31 by means of a pivoting joint connection.
[0070] The articulated connection 16 has here a vertical pivoting
joint 33, wherein the first cantilever arm 14 and the second
cantilever arm 15 are connected to the vertical pivoting joint 33.
The vertical pivoting joint 33 has a rotational axis 34 which is
embodied vertically with respect to the longitudinal extent or
vertically with respect to the longitudinal axis 24, 25 of the
cantilever arms 14, 15, with the result that when the tugger train
100 is cornering the cantilever arms 14, 15 can be pivoted about
the vertical pivoting joint 33, which is embodied in the form of a
shaft, or about the rotational axis 34 of the vertical pivoting
joint 33, as is indicated in FIG. 5. During cornering, the
corresponding connecting rods 26, 27, 28, 29 are displaced in the
linear guide 30, 31 in such a way that by means of the connecting
rods 26, 27, 28, 29 the corresponding cantilever arm 14, 15 is
pivoted to the side necessary for cornering.
[0071] FIGS. 6 and 7 show an embodiment of a steering device in
which the steering device is embodied in the form of a gear
unit.
[0072] The gear unit has a first gear wheel 36, a second gear wheel
37, a third gear wheel 38 and a fourth gear wheel 39, wherein all
the gear wheels 36, 37, 38, 39 are embodied here as toothed wheels,
in particular as bevel gears. The first gear wheel 36 is connected
to the first cantilever arm 14 by a connecting element 40, wherein
the first gear wheel 36 forms a drive wheel. The second gear wheel
37 is connected to the second cantilever arm 15 via a connecting
element 41, wherein the second gear wheel 37 forms a drive wheel.
The first gear wheel 36 and the second gear wheel 37 are arranged
parallel to one another on the vertical pivoting joint 33 of the
articulated connection 16. The third gear wheel 38 and the fourth
gear wheel 39, which are arranged lying opposite one another, are
each connected to the wheel axle 12 or the frame of the wheel axle
12. The third gear wheel 38 and the fourth gear wheel 39 are each
arranged between the first gear wheel 36 and the second gear wheel
37, with the result that, for example, a rotational movement of the
first gear wheel 36 can be transmitted to the second gear wheel 37
via the third and fourth gear wheels 38, 39. As a result of the
fact that in the embodiment of the gear unit shown here two gear
wheels 38, 39 are provided which are connected to the wheel axle 12
and are arranged between the first gear wheel 36 and the second
gear wheel 37, force can be applied symmetrically to the wheel axle
12 or to the frame of the wheel axle 12 when there is a rotational
movement of the gear wheels 36, 37, 38, 39.
[0073] The gear unit forms a type of "minus gear unit" which has a
gear stage. A rotational movement of the first cantilever arm 14,
for example in the clockwise direction, can be transformed into a
rotational movement of the second cantilever arm 15 in the
anti-clockwise direction, and vice versa, by means of the gear
wheels 36, 37, 38, 39 which engage one in the other. The 1:1
transmission ratio of the gear unit, which is implemented by the
same pitch circle diameters of the first gear wheel 36 embodied as
a drive wheel and the second gear wheel 37 embodied as an output
wheel, permits the wheel axle 12 to be steered into an
angle-bisecting position between the first cantilever arm 13 and
the second cantilever arm 15, with the result that the first, front
steering angle .alpha..sub.v corresponds to the second, rear
steering angle .alpha..sub.h.
[0074] FIGS. 8 to 10 show embodiments of the steering device as a
spring-damper system.
[0075] In the embodiment shown in FIG. 8 of a spring-damper system,
a first spring element 42 is arranged between the wheel axle 12 and
the first cantilever arm 14. A second spring element 43 is arranged
between the wheel axle 12 and the second cantilever arm 15. Both
the first spring element 42 and the second spring element 43 are
embodied here as linear springs. In addition, a damper element 44
is arranged between the wheel axle 12 and the second cantilever arm
15, parallel to the second spring element 43. As a result of the
damper element 44, when the tugger train 100 is cornering the
second cantilever arm 15 is rotated more slowly with respect to the
wheel axle 12 than the first cantilever arm 14. The first, front
steering angle .alpha..sub.v therefore changes more quickly during
cornering than the second, rear steering angle .alpha..sub.h, but
the spring-damper system also operating in such a way that even
when there is a temporarily different magnitude of the first, front
steering angle .alpha..sub.v compared to the second, rear steering
angle .alpha..sub.h, the steering device attempts to steer the
wheel axle 12 into an angle-bisecting position between the first
cantilever arm 14 and the second cantilever arm 15.
[0076] In the case of straight-ahead travel of the tugger train
100, i.e. when the bending angle .gamma.=180.degree., the spring
elements 42, 43 are in a force equilibrium. In contrast, when the
tugger train 100 is cornering, one of the spring elements 42, 43 is
stressed and the other spring element 42, 43 is relaxed, with the
result that an imbalance in forces is brought about, but the spring
elements 42, 43 attempt to compensate this imbalance in forces
again as quickly as possible in that the wheel axle 12 is steered
again into an angle-bisecting position between the first cantilever
arm 14 and the second cantilever arm 15.
[0077] FIGS. 9 and 10 show an embodiment of a steering device as a
spring-damper system in which a first spring element 42 is also
connected to the wheel axle 12 and to the first cantilever arm 14,
and a second spring element 43 is connected to the wheel axle 12
and to the second cantilever arm 15. The two spring elements 42, 43
are embodied here as torsion or torsional springs which are
arranged on the vertical pivoting joint 33 of the articulated
connection 16. In addition, the spring-damper system shown in FIGS.
9 and 10 has three damper elements 45, 46, 47, which are each
connected by a first end to the wheel axle 12 and by a second end
to an attachment frame 48 connected to the second cantilever arm
15. The attachment frame 48 is embodied essentially in a U shape
when viewed from above in a plan view. A first damper element 45
and a second damper element 46 are arranged inclined at an angle
<90.degree. with respect to the longitudinal extent of the wheel
axle 12 and are connected to a first left-hand side, when viewed in
the direction of travel 17, of the wheel axle 12. A third damper
element 47 is arranged at an angle of approximately 90.degree. and
therefore vertically with respect to the longitudinal extent of the
wheel axle 12, and is connected to a second right-hand side, when
viewed in the direction of travel, of the wheel axle 12, lying
opposite the first side.
[0078] The two spring elements 42, 43 which are arranged axially
with respect to one another and with respect to the vertical
pivoting joint 33 permit the wheel axle 12 to be steered into an
angle-bisecting position between the first cantilever arm 14 and
the second cantilever arm 15. However, the angle-bisecting position
is to be reached with a delay in the case of cornering in order to
achieve the highest possible directional stability. When entering
the bend it is therefore advantageous if the second, rear steering
angle .alpha..sub.h is larger for a defined time than the first,
front steering angle .alpha..sub.v. When exiting the bend it is
advantageous if the second, rear steering angle .alpha..sub.h is
smaller for a defined time than the first, front steering angle
.alpha..sub.v. This type of delay in the splitting of the angle is
implemented by using the linear damper elements 45, 46, 47. The
specific arrangement and position of the damper elements 45, 46,
47, as shown in FIGS. 9 and 10, permits the kinematics of the axle
modules 11 to be utilized to "switch off" the damping effect
depending on the position of the wheel axle 12. As result, an ideal
trailing behaviour and a high level of directional stability of the
tugger train 100 is implemented over a large number of driving
maneuvers.
[0079] When entering a bend, the first cantilever arm 14 is
deflected outwards, as a result of which the first spring element
42 is stressed. A difference in torque between the first spring
element 42 and the second spring element 43 which results from this
forces the wheel axle 12 to move, wherein the wheel axle 12 is
delayed in its movement or rotational movement by the damper
elements 45, 46, 47. If the size of the first, front steering angle
.alpha..sub.v increases, the effect of the damper elements 45, 46,
47 decreases owing to reducing differences in torque in the spring
elements 42, 43 and the additional effect of the kinematics, until
an angle-bisecting position of the wheel axle 12 is reached again,
at which position the first, front steering angle .alpha..sub.v is
equal to the second, rear steering angle .alpha..sub.h.
[0080] FIG. 11 shows once more an illustration of a detail of a
connection of a bogie frame 19 to the last axle module 11 of the
tugger train 100. The bogie frame 19, in particular the wheel axle
20 of the bogie frame 19, can, like the wheel axle 12 of the last
axle module 11, be rotated in relation to the second cantilever arm
15, about a rotational axis vertically with respect to the
longitudinal extent of the second cantilever arm 15. Steering
kinematics, here in the form of a Bissell bogie 50, are embodied
between the wheel axle 12 of the last axle module 11 and the bogie
frame 19 or the wheel axle 20 of the bogie frame 19 in such a way
that the bogie frame 19 is rotated with respect to the cantilever
arm 15 with an equally large angle to the wheel axle 12 of the last
axle module 11, but in the opposite direction. In the case of the
axle module 11 shown in FIG. 12, the articulated connection 16
additionally has a horizontal pivoting joint 51 which is arranged
here in the second cantilever arm 15 itself, with the result that
the second cantilever arm 15 is divided into two component elements
52, 53 which are movable with respect to one another. The
horizontal pivoting joint 51 is embodied here in the form of a
shaft which is arranged transversely with respect to the
longitudinal extent or longitudinal axis 25 of the second
cantilever arm 15. The horizontal pivoting joint 51 therefore has a
rotational axis 54 which, at least in the case of straight-ahead
travel of the tugger train 100, extends transversely with respect
to the direction of travel 17 of the tugger train 100 or extends
transversely with respect to the longitudinal axis 24, 25 of the
respective cantilever arm 14, 15 on which the horizontal pivoting
joint 51 is arranged.
[0081] The distance a between the horizontal pivoting joint 51 and
the wheel axle 12 is preferably embodied as small as possible. In
the embodiment shown in FIG. 12, the distance a>0. It is
particularly preferred if the distance a=0, wherein the horizontal
pivoting joint 51 between the respective cantilever arm 14, 15 and
the wheel axle 12 would preferably be embodied in the form of a
Cardan joint.
[0082] FIG. 13 shows a further embodiment of an axle module 11 in
which the articulated connection 16 has not only a vertical
pivoting joint but a first vertical pivoting joint 33a and a second
vertical pivoting joint 33b. The first cantilever arm 14 is
connected indirectly to the wheel axle 12 via the first vertical
pivoting joint 33a, and the second cantilever arm 15 is connected
indirectly to the wheel axle 12 via the second vertical pivoting
joint 33b, wherein the first vertical pivoting joint 33a and the
second vertical pivoting joint 33b are arranged on a common plate
55, which is in turn fixedly connected to the wheel axle 12.
[0083] Further possible embodiments of a connection of the last
axle module 11, when viewed in the direction of travel 17 of the
tugger train 100, to the bogie frame 19 are shown in FIGS. 15, 17
and 19.
[0084] As is shown by means of FIGS. 14, 16 and 18, the method of
operation of the steering kinematics for the bogie frame 19 depends
on the length ratio of the length L.sub.I, which constitutes the
distance between the articulated connection 16 of the last axle
module 11 and the bogie frame 19, and therefore the length of the
second cantilever arm 15 of the last axle module 11, and the length
L.sub.v, which constitutes the distance between the last axle
module 11 and an axle module 11 which is arranged ahead of the last
axle module 11 when viewed in the direction of travel 17.
[0085] Given a length ratio of L.sub.I>0.5 L.sub.v, the bogie
frame 19 or the wheel axle 20 of the bogie frame 19 should be
steered in the opposite direction to the last axle module 11 or the
last wheel axle 12 of the last axle module 11, in order to be able
to ensure directional stability of the entire tugger train 100 in
the case of steady-state cornering of the tugger train 100.
[0086] FIG. 14 shows a boundary case in which a length ratio of
L.sub.I=L.sub.v is formed.
[0087] FIG. 15 shows possible counter-steering of the bogie frame
19 in the case of a length ratio of L.sub.I=L.sub.v, as is shown in
FIG. 14. For this, a Bissell bogie 50 is arranged between the last
axle module 11 and the bogie frame 19. The wheel axle 20 of the
bogie frame 19 can be rotated relative to the second cantilever arm
15 of the last axle module 11, with the result that the steering
angle .alpha..sub.I of the bogie frame 19 can be changed. The
steering angle .alpha..sub.I of the bogie frame 19 is stretched
between the second cantilever arm 15 and the wheel axle 20 of the
bogie frame 19.
[0088] The Bissell bogie 50 has a guide element 56 which is
displaceably guided along the longitudinal extent of the second
cantilever arm 15 of the last axle module 11. The second cantilever
arm 15 has a cut-out 57 in the form of an elongated hole which
extends in the longitudinal direction of the second cantilever arm
15, wherein the guide element 56 is mounted in a displaceably
movable fashion in the cut-out 57. The guide element 56 is embodied
here in the form of a plate. The guide element 56 is connected to
the wheel axle 12 of the last axle module 11 via a first connecting
rod 58. The guide element 56 is connected to the wheel axle 20 of
the bogie frame 19 via a second connecting rod 59. The second
connecting rod 59 is mounted on an end section of the guide element
56 which is embodied opposite an end section of the guide element
56 at which the first connecting rod 58 is mounted on the guide
element 56.
[0089] With the Bissell bogie 50 it is possible to ensure that the
steering angle .alpha..sub.I of the bogie frame 19 is of the same
size as the rear steering angle .alpha..sub.h which is stretched
between the wheel axle 12 of the last axle module 11 and the second
cantilever arm 15. As a result of the fact that a ratio of the
steering angles of .alpha..sub.I=.alpha..sub.h can be set with the
Bissell bogie 50, directional stability of the entire tugger train
can be ensured in the case of steady-state circular travel of the
tugger train 100.
[0090] FIG. 16 shows a further embodiment in which a length ratio
of L.sub.i=0.5 L.sub.v is formed. Given this length ratio, the
wheel axle 20 of the bogie frame 19 should be constantly oriented
perpendicularly with respect to the second cantilever arm 15 of the
last axle module 11, with the result that a steering angle
.alpha..sub.I of 90.degree. is formed. As is illustrated in FIG.
17, for this purpose the bogie frame 19 or the wheel axle 20 of the
bogie frame 19 can be fixedly or rigidly connected to the second
cantilever arm 15. Given a length ratio of L.sub.I=0.5 L.sub.v a
ratio of the steering angles of .alpha..sub.I=.alpha..sub.h can
also be set as result of this, so that directional stability of the
entire tugger train can also be ensured here given steady-state
circular travel of the tugger train 100.
[0091] FIG. 18 shows a further embodiment in which a length ratio
of L.sub.I<0.5 L.sub.v is formed. Given such a length ratio, the
wheel axle 20 of the bogie frame 19 should be steered in the same
direction as the wheel axle 12 of the last axle module 11 when
viewed in the direction of travel 17 of the tugger train 100, as is
shown in FIG. 19, in order to ensure directional stability of the
entire tugger train during steady-state circular travel of the
tugger train 100. In order to achieve this, a connecting rod 60,
which forms a Bissell bogie 50, is preferably arranged between the
wheel axle 12 of the last axle module 11 and the wheel axle 20 of
the bogie frame 19, which connecting rod 60 is mounted in an
articulated fashion on the wheel axle 12 of the last axle module 11
and on the wheel axle 20 of the bogie frame 19. The Bissell bogie
50 is therefore formed only by a connecting rod 60 in this
embodiment.
[0092] The distance between the articulated connection of the
connecting rod 60 and the wheel axle 12 of the last axle module 11
and the articulated connection 16 is larger than the distance
between the articulated connection of the connecting rod 60 and the
wheel axle 20 of the bogie frame 19. As a result, the angle between
the wheel axle 12 and the second cantilever arm 15 is always larger
than the angle between the cantilever arm 15 and the wheel axle 20
of the bogie frame 19, with the result that in the case of
steady-state circular travel of the tugger train 100 directional
stability of the entire tugger train and, in particular, of the
last axle module 11 and of the bogie frame 19 can also be ensured
here.
[0093] The connecting rod 60 is guided along a side of the second
cantilever arm 15, with the result that the connecting rod 60 does
not pass over or overlap or cross the second cantilever arm 15.
[0094] The invention is therefore not restricted in its embodiment
to the preferred exemplary embodiments specified above. Instead, a
number of variants which make use of the illustrated solutions even
in embodiments of basically different type are conceivable. All of
these features and/or advantages, including structural details,
spatial arrangements and method steps, which can be found in the
claims, the description or the drawings, can be essential to the
invention both per se as well as in the extremely wide variety of
combinations.
LIST OF REFERENCE NUMBER
[0095] 100 tugger train [0096] 10 transportation module [0097] 11
axle module [0098] 12 wheel axle [0099] 13 wheel [0100] 14 first
cantilever arm [0101] 15 second cantilever arm [0102] 16
articulated connection [0103] 17 direction of travel [0104] 18
towing vehicle [0105] 19 bogie frame [0106] 20 wheel axle [0107] 21
wheel [0108] 22 connecting element [0109] 23 connecting element
[0110] 24 longitudinal axis [0111] 25 longitudinal axis [0112] 26
first connecting rod [0113] 27 third connecting rod [0114] 28
second connecting rod [0115] 29 fourth connecting rod [0116] 30
linear guide [0117] 31 linear guide [0118] 32 sliding element
[0119] 33 vertical pivoting joint [0120] 33a vertical pivoting
joint [0121] 33b vertical pivoting joint [0122] 34 rotational axis
[0123] 35 cut-out [0124] 36 first gear wheel [0125] 37 second gear
wheel [0126] 38 third gear wheel [0127] 39 fourth gear wheel [0128]
40 connecting element [0129] 41 connecting element [0130] 42 first
spring element [0131] 43 second spring element [0132] 44 damper
element [0133] 45 damper element [0134] 46 damper element [0135] 47
damper element [0136] 48 attachment frame [0137] 49 angular profile
[0138] 50 Bissell bogie [0139] 51 horizontal pivoting joint [0140]
52 component element [0141] 53 component element [0142] 54
rotational axis [0143] 55 plate [0144] 56 guide element [0145] 57
cut-out [0146] 58 connecting rod [0147] 59 connecting rod [0148] 60
connecting rod [0149] 61 supporting arm [0150] 62 supporting arm
[0151] 63 coupling element [0152] 64 coupling element [0153] 65
full-floating axle
* * * * *