U.S. patent application number 17/516998 was filed with the patent office on 2022-05-05 for method for compacting asphalt material.
The applicant listed for this patent is Hamm AG. Invention is credited to Klaus MEINDL, Axel MUHLHAUSEN, Frank STEGNER.
Application Number | 20220136184 17/516998 |
Document ID | / |
Family ID | 1000006008887 |
Filed Date | 2022-05-05 |
United States Patent
Application |
20220136184 |
Kind Code |
A1 |
MUHLHAUSEN; Axel ; et
al. |
May 5, 2022 |
METHOD FOR COMPACTING ASPHALT MATERIAL
Abstract
A method for compacting asphalt material (A) by means of at
least one soil compactor (10) having at least one compactor roller
with a motion generation arrangement assigned to the same,
comprising the measures: a) detection of an asphalt temperature of
the asphalt material (A) to be compacted, b) static compaction of
the asphalt material (A) with a deactivated motion generation
arrangement of the at least one compactor roller, if the asphalt
temperature lies above an upper threshold temperature (O), c)
static compaction of the asphalt material (A) with a deactivated
motion generation arrangement of the at least one compactor roller,
if the asphalt temperature lies below a lower threshold temperature
(U), wherein the upper threshold temperature (O) and/or the lower
threshold temperature (U) is/are set depending on at least one
surroundings parameter (T) influencing the cooling behavior of the
asphalt material to be compacted.
Inventors: |
MUHLHAUSEN; Axel; (Weiden,
DE) ; MEINDL; Klaus; (Barnau, DE) ; STEGNER;
Frank; (Luhe-Wildenau, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamm AG |
Tirschenreuth |
|
DE |
|
|
Family ID: |
1000006008887 |
Appl. No.: |
17/516998 |
Filed: |
November 2, 2021 |
Current U.S.
Class: |
404/122 |
Current CPC
Class: |
E01C 19/255 20130101;
E01C 19/286 20130101; E01C 19/238 20130101 |
International
Class: |
E01C 19/23 20060101
E01C019/23; E01C 19/25 20060101 E01C019/25; E01C 19/28 20060101
E01C019/28 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 3, 2020 |
DE |
10 2020 128 842.5 |
Claims
1. Method for compacting asphalt material by at least one soil
compactor having at least one compactor roller with a motion
generation arrangement assigned to the same, comprising: a)
detecting of an asphalt temperature of the asphalt material to be
compacted, b) statically compacting of the asphalt material with a
deactivated motion generation arrangement of the at least one
compactor roller, if the asphalt temperature lies above an upper
threshold temperature, c) statically compacting the asphalt
material with a deactivated motion generation arrangement of the at
least one compactor roller, if the asphalt temperature lies below a
lower threshold temperature, wherein the upper threshold
temperature and/or the lower threshold temperature is/are set
depending on at least one surroundings parameter influencing the
cooling behavior of the asphalt material to be compacted.
2. Method according to claim 1, wherein the upper threshold
temperature and/or the lower threshold temperature is/are set
depending on at least two surroundings parameters influencing the
cooling behavior of the asphalt material to be compacted.
3. Method according to claim 1, wherein the upper threshold
temperature and/or the lower threshold temperature is/are set
depending on a surroundings temperature as the surroundings
parameter influencing the cooling behavior of the asphalt material
to be compacted.
4. Method according to claim 3, wherein the upper threshold
temperature is increased at a decreasing surroundings temperature,
and/or that the lower threshold temperature is decreased at
decreasing surroundings temperature.
5. Method according to claim 1, wherein the upper threshold
temperature and/or the lower threshold temperature is/are set
depending on a wind speed as the surroundings parameter influencing
the cooling behavior of the asphalt material to be compacted.
6. Method according to claim 5, wherein the upper threshold
temperature is increased at an increasing wind speed, and/or that
the lower threshold temperature is decreased at an increasing wind
speed.
7. Method according to claim 1, wherein the asphalt material to be
compacted is compacted using an activated motion generation
arrangement of at least one compactor roller at an asphalt
temperature lying in an intermediate temperature range, delimited
by the upper threshold temperature and the lower threshold
temperature.
8. Method according to claim 7, wherein, in an upper temperature
range of the intermediate temperature range adjacent to the upper
threshold temperature, the motion generation arrangement of at
least one compactor roller is operated in a motion excitation
operating state with a larger energy input, and that, in a lower
temperature range of the intermediate temperature range adjacent to
the lower threshold temperature, the motion generation arrangement
of at least one compactor roller is operated in a motion excitation
operating state (k) with a lower energy input.
9. Method according to claim 8, wherein the motion generation
arrangement is drivable in a plurality of discrete motion
excitation operating states with different energy inputs, and that
the motion generation arrangement is operated in a motion
excitation operating state with a larger energy input at an asphalt
temperature lying above at least one intermediate threshold
temperature lying in the intermediate temperature range, and is
operated in a motion excitation operating state with a lower energy
input at an asphalt temperature lying below the at least one
intermediate threshold temperature.
10. Method according to claim 9, wherein the motion generation
arrangement is drivable in two motion excitation operating states
with different energy inputs, and that the motion generation
arrangement is operated in a motion excitation operating state with
a higher energy input at an asphalt temperature lying above the
intermediate threshold temperature, and is operated in a motion
excitation operating state with a lower energy input at an asphalt
temperature lying below the intermediate threshold temperature.
11. Method according to claim 8, wherein at least one intermediate
threshold temperature is set depending on at least one surroundings
parameter influencing the cooling behavior of the asphalt material
to be compacted.
12. Method according to claim 11, wherein the intermediate
threshold temperature is set depending on the surroundings
temperature as the surroundings parameter influencing the cooling
behavior of the asphalt material to be compacted.
13. Method according to claim 12, wherein the intermediate
threshold temperature is decreased at a decreasing surroundings
temperature.
14. Method according to claim 11, wherein the intermediate
threshold temperature is set depending on the wind speed as the
surroundings parameter influencing the cooling behavior of the
asphalt material to be compacted.
15. Method according to claim 14, wherein the intermediate
threshold temperature is decreased at an increasing wind speed.
16. Method according to claim 7, wherein the motion generation
arrangement is operable with an energy input continuously variable
between a minimum energy input and a maximum energy input.
17. Method according to claim 16, wherein, for an asphalt
temperature lying at or in the range of the upper threshold
temperature, the motion generation arrangement is operated with a
maximum energy input, and/or that for an asphalt temperature lying
at or in the range of the lower threshold temperature, the motion
generation arrangement is operated with a minimum energy input.
18. Method according to claim 1, wherein the motion generation
arrangement assigned to at least one compactor roller is a
vibration arrangement, and/or that the motion generation
arrangement assigned to at least one compactor roller is an
oscillation arrangement.
19. Method according to claim 18, wherein at least one soil
compactor has two compactor rollers, wherein a vibration
arrangement is assigned to each compactor roller, and/or that at
least one soil compactor has two compactor rollers, wherein a
vibration arrangement is assigned to one of the compactor rollers
and an oscillation arrangement is assigned to the other compactor
roller.
Description
[0001] The present invention relates to a method for compacting
asphalt material.
[0002] In order to compact asphalt material, for example in road
construction, soil compactors are used, among others, which have at
least one compactor roller with a motion generation arrangement
assigned to the same. When the motion generation arrangement is
deactivated, the asphalt material to be compacted is compacted
statically by this type of compactor roller, thus by the weight
load exerted by the compactor roller. When the motion generation
arrangement is activated, additional energy is introduced into the
compactor roller and via the same into the asphalt material to be
compacted due to the excitation of the compactor roller to
oscillate or due to the generation of a deflection movement of the
compactor roller. The deflection movement or oscillation, generated
by the motion generation arrangement, is superimposed on the
rolling movement of the compactor roller during movement of a soil
compactor across the asphalt material to be compacted.
[0003] This type of motion generation arrangement, provided in
assignment to a compactor roller in a soil compactor used to carry
out the method according to the invention, may be designed as a
vibration arrangement, through which an acceleration or force is
exerted on the compactor roller substantially orthogonal to a
rotational axis of the compactor roller. This type of vibration
arrangement may comprise in the interior of the compactor roller an
unbalanced mass arrangement, with a center of mass eccentric to the
unbalanced rotational axis, drivable by an unbalance drive to
rotate about an unbalanced rotational axis. The unbalanced
rotational axis may, for example, correspond to the rotational axis
of the assigned compactor roller. In order to be able to set
different operating states with different energy inputs for this
type of vibration arrangement, and thus to be able to generate
different vibration amplitudes in the assigned compactor roller,
the unbalanced mass arrangement may comprise mass parts movable
with respect to one another, so that the mass acting in the center
of mass is changeable and/or the radial distance of the center of
mass of the unbalanced mass arrangement to the unbalanced
rotational axis is changeable. For example, to change the mass
acting in the center of mass, two mass parts may assume different
angular positions from one another about the unbalanced rotational
axis depending on the direction of rotation of the unbalanced mass
arrangement. Alternatively or additionally, to change the energy
introduced into the compactor roller or into the asphalt material,
the rotational speed of a respective unbalanced arrangement and
thus the vibration frequency may be changed. Compactor rollers with
these assigned vibration arrangements are generally designated as
vibratory rollers. Soil compactors with compactor rollers with
these assigned vibration arrangements are known from DE 10 2016 109
888 A1 and DE 10 2018 132 379 A1. Vibration arrangements are known
from WO 2018/23633 A1 and also CN 201801803 U, which, by changing
the direction of rotation, may be switched between two operating
states with different positions of two mass parts of an unbalanced
mass arrangement to one another, and thus masses acting in a
different center of mass.
[0004] In one alternative embodiment, an oscillation arrangement
may be assigned to this type of compactor roller, by means of said
oscillation arrangement a periodically changing torque is generated
to act on the compactor roller about its rotational axis. This type
of oscillation arrangement may comprise multiple unbalanced mass
arrangements, drivable by an unbalance drive to rotate about
unbalanced rotational axes eccentric to the rotational axis of the
assigned compactor roller. By matching the rotational movement of
the unbalanced mass arrangements about the respectively assigned
unbalanced rotational axes to one another, the periodically
changing torque acting about the rotational axis of the compactor
roller is generated in the circumferential direction. In these
types of oscillation arrangements as well, each unbalanced mass
arrangement may comprise mass parts movable with respect to one
another so that the mass acting in the center of mass and/or the
radial distance of the center of mass of the respective unbalanced
mass arrangement to the unbalanced rotational axis is changeable,
in order to change the energy introduced into the compactor roller
and thus also into the asphalt material to be compacted, or to
change the oscillation amplitude generated in the respective
compactor roller. For example, to change the mass acting in a
respective center of mass of a mass arrangement, two mass parts may
assume different angular positions from one another about the
respective unbalanced rotational axis depending on the direction of
rotation of the unbalanced mass arrangement. Alternatively or
additionally, to change the energy introduced into the compactor
roller or into the substrate, the rotational speed of the
unbalanced mass arrangements and thus the oscillation frequency may
be changed. Compactor rollers having these assigned oscillation
arrangements are generally designated as oscillating rollers. This
type of oscillation arrangement or a soil compactor with a
compactor roller having an oscillation arrangement assigned to the
same is known, for example, from WO 2019/063540 A1. Oscillation
arrangements are known from DE 10 2017 122 371 A1 and DE 10 2015
112 847 A1, in which the oscillation torque or the amplitude of the
oscillation movement is substantially continuously variable. WO
2013/013819 A1 discloses an oscillation arrangement, in which, by
changing the direction of rotation, a switching between operating
states with different oscillation amplitudes is achievable by
displacing mass parts in unbalanced mass arrangements eccentric to
the rotational axis of a compactor roller. By arranging this type
of unbalanced mass arrangement centrally to the rotational axis of
a compactor roller, this could be used as a vibration
arrangement.
[0005] A soil compactor roller, used to carry out the method
according to the invention, has at least one compactor roller with
this assigned motion generation arrangement arranged generally
therein, for example, a motion generation arrangement as is known
from the previously listed prior art. The motion generation
arrangement may be designed as a vibration arrangement or as an
oscillation arrangement. A combination of a vibration arrangement
and an oscillation arrangement in one and the same compactor roller
may also be provided. Furthermore, a soil compactor, used to carry
out the method according to the invention, may have two compactor
rollers, which have the same motion generation arrangements, thus a
vibration arrangement or an oscillation arrangement respectively,
or have different motion generation arrangements, so that a
vibration arrangement is provided in one of the compactor rollers
and an oscillation arrangement is provided in the other compactor
roller.
[0006] It is the object of the present [invention] to provide a
method for compacting asphalt material by means of at least one
soil compactor having at least one compactor roller with a motion
generation arrangement assigned to the same, with which a
compaction state of the asphalt material to be compacted may be
achieved which is substantially unimpaired by external
influences.
[0007] According to the invention, this problem is solved by a
method for compacting asphalt material by means of at least one
soil compactor having at least one compactor roller with a motion
generation arrangement assigned to the same, comprising the
measures: [0008] a) detection of an asphalt temperature of the
asphalt material to be compacted, [0009] b) static compaction of
the asphalt material with a deactivated motion generation
arrangement of the at least one compactor roller, if the asphalt
temperature lies above an upper threshold temperature, [0010] c)
static compaction of the asphalt material with a deactivated motion
generation arrangement of the at least one compactor roller, if the
asphalt temperature lies below a lower threshold temperature,
wherein the upper threshold temperature and/or the lower threshold
temperature are set depending on at least one surroundings
parameter influencing the cooling behavior of the asphalt material
to be compacted.
[0011] In the method according to the invention, it may be
guaranteed by suitable adjustment of the upper threshold
temperature or the lower threshold temperature, depending on the
circumstances which influence the cooling behavior of the asphalt
material, that sufficient time is available for the compacting
measures to be carried out in the course of the method. In
particular, it is ensured by adjusting the upper threshold
temperature or the lower threshold temperature that a compaction
with an activated motion generation arrangement is prevented in a
state of the asphalt material, in which this is not suitable or
logical. Further, by adjusting the upper threshold temperature or
the lower threshold temperature depending on surroundings
conditions, the temperature window, defined between these threshold
temperatures, which takes into account the fact that the asphalt
material gradually cools down, corresponds to a time window that
provides sufficient time in order to be able to compact the asphalt
material using an activated motion generation arrangement, for
example, according to a compaction plan provided for this, between
these threshold temperatures. A state may thus be avoided, in which
this time window is too short, and thus the provided compaction
plan may not be processed or there is a risk that an operator of a
compactor makes mistakes in the operation of the soil compactor,
due to the resulting time pressure.
[0012] An increased precision in the consideration of surroundings
conditions during compaction of asphalt material may be achieved in
that the upper threshold temperature and/or the lower threshold
temperature is/are set depending on at least two surroundings
parameters influencing the cooling behavior of the asphalt material
to be compacted.
[0013] If the upper threshold temperature and/or the lower
threshold temperature is/are set depending on a surroundings
temperature as the surroundings parameter influencing the cooling
behavior of the asphalt material to be compacted, then a factor
substantially influencing the gradual cooling down of the asphalt
material may be taken into consideration.
[0014] In order to maintain the time window to be as large as
possible for processing the asphalt material with an active motion
generation arrangement, while taking the surroundings temperature
into consideration, it is proposed that the upper threshold
temperature is increased at a decreasing surroundings temperature,
and/or that the lower threshold temperature is decreased at a
decreasing surroundings temperature.
[0015] Another parameter substantially influencing the cooling
behavior of asphalt material is wind speed. Therefore, according to
the invention, the upper threshold temperature and/or the lower
threshold temperature may be set depending on a wind speed as the
surroundings parameter influencing the cooling behavior of the
asphalt material to be compacted.
[0016] In order to also maintain the available time window to be as
large as possible for carrying out a compaction process with an
active motion generation arrangement, while taking the wind speed
into consideration, it may be provided that the upper threshold
temperature is increased at an increasing wind speed, and/or that
the lower threshold temperature is decreased at an increasing wind
speed.
[0017] The asphalt material to be compacted may be compacted using
an activated motion generation arrangement of at least one
compactor roller at an asphalt temperature lying in an intermediate
temperature range delimited by the upper threshold temperature and
the lower threshold temperature. Therefore, this may also primarily
be carried out, since, at an asphalt temperature above the upper
threshold temperature, the asphalt material is statically compacted
according to the method according to the invention and therefore,
this is already compacted to an extent that, upon reaching or
dropping below the upper threshold temperature, and thereby at an
always still comparatively warm asphalt material, the activation of
a motion generation arrangement does not disadvantageously
influence the structure of the asphalt material, but instead may
actually cause further compaction.
[0018] In order to be able to use the state, in which the asphalt
material has a sufficient, yet not too high flowability, to
optimally introduce energy, it is proposed that, in an upper
temperature range of the intermediate temperature range adjacent to
the upper threshold temperature, the motion generation arrangement
of at least one compactor roller is operated in a motion excitation
operating state with a larger energy input, and that, in a lower
temperature range of the intermediate temperature range adjacent to
the lower threshold temperature, the motion generation arrangement
of at least one compactor roller is operated in a motion excitation
operating state with a smaller energy input.
[0019] For example, it may be provided that the motion generation
arrangement is drivable in a plurality of discrete motion
excitation operating states with different energy inputs, and that
the motion generation arrangement is operated in a motion
excitation operating state with a larger energy input at an asphalt
temperature lying above at least one intermediate threshold
temperature lying in the intermediate temperature range, and is
operated in a motion excitation operating state with a smaller
energy input at an asphalt temperature lying below the at least one
intermediate threshold temperature.
[0020] This may be achieved in a structurally easy to realize
embodiment of a soil compactor used to carry out a method according
to the invention, in that the motion generation arrangement is
operable in two, that is exactly or only two motion excitation
operating states with different energy inputs, and that the motion
generation arrangement is operated in the motion excitation
operating state with a higher energy input at an asphalt
temperature lying above the intermediate threshold temperature, and
is operated in the motion excitation operating state with a lower
energy input at an asphalt temperature lying below the intermediate
threshold temperature.
[0021] In order to be able to see the cooling behavior of the
asphalt material to be compacted or the circumstances influencing
the same, also when switching between different motion excitation
operating states, it may further be provided that at least one
intermediate threshold temperature is set depending on at least one
surroundings parameter influencing the cooling behavior of the
asphalt material to be compacted.
[0022] For example, the intermediate threshold temperature may be
set depending on the surroundings temperature as the surroundings
parameter influencing the cooling behavior of the asphalt material
to be compacted, wherein this may proceed such that the
intermediate threshold temperature is decreased at a decreasing
surroundings temperature.
[0023] Alternatively or additionally, the intermediate threshold
temperature may also be set depending on the wind speed as the
surroundings parameter influencing the cooling behavior of the
asphalt material to be compacted. For example, the intermediate
threshold temperature may be decreased at increasing wind
speed.
[0024] In one alternative embodiment type of a soil compactor or a
compactor roller, the motion generation arrangement assigned to the
same may be operable with an energy input that is continuously
variable between a minimum energy input and a maximum energy input.
This enables a finely metered adjustment of the energy input to the
changing degree of compaction or to the changing temperature of the
asphalt material. For example, this continuous change of the energy
input may be achieved in that two mass parts of an unbalanced mass
arrangement are continuously displaced with respect to one another
by an assigned actuator in order to thus correspondingly
continuously change the position of the center of mass or the mass
acting in the center of mass of this type of unbalanced mass
arrangement.
[0025] In order to be able to introduce the energy necessary to
achieve the desired degree of compaction of the asphalt material in
this type of embodiment during the cooling down of the asphalt
material, it is proposed that, for an asphalt temperature lying at
or in the range of the upper threshold temperature, the motion
generation arrangement is operated with maximum energy input,
and/or that for an asphalt temperature lying at or in the range of
the lower threshold temperature, the motion generation arrangement
is operated with minimum energy input. The energy input may be
changed between these two states, thus the state with the maximum
energy input and the state with the minimum energy input, for
example, linearly.
[0026] In this context, reference is made to the fact that, in the
meaning of the present invention, a motion generation arrangement
is then in a motion excitation operating state with maximum energy
input, for example, when a maximum motion amplitude is generated at
the assigned compactor roller, and/or the force or acceleration or
the amplitude thereof acting on the compactor roller is maximal.
Equally, in the meaning of the present invention, a motion
generation arrangement is, for example, in a motion excitation
operating state with minimum energy input, when the induced motion
amplitude or the force or acceleration or amplitude thereof acting
on the compactor roller is zero, or a minimal value other than zero
when the motion generation arrangement is operated with a non-zero
minimum value of the energy input. In this respect, a motion
excitation operating state with a minimum energy input of zero may
correspond to a deactivated state of a motion generation
arrangement.
[0027] The at least one motion generation arrangement, assigned to
a compactor roller, may be a vibration arrangement. Furthermore,
the at least one motion generation arrangement, assigned to a
compactor roller, may be an oscillation arrangement.
[0028] If the motion generation arrangement [is] a vibration
arrangement, it is particularly advantageous to induce the change
of the energy input primarily or exclusively by changing the
amplitude of the vibration to be generated or the deflection
movement of a compactor roller, while the vibration frequency, for
example, may be maintained substantially constant, or it may be
changed to adjust to the movement speed of a soil compactor across
the asphalt material to be compacted.
[0029] Furthermore, at least one soil compactor used to carry out
the method according to the invention may have two compactor
rollers, wherein a vibration arrangement is assigned to each
compactor roller. It may also be provided that, at least one soil
compactor used to carry out the method according to the invention
may have two compactor rollers, wherein a vibration arrangement is
assigned to one of the compactor rollers and an oscillation
arrangement is assigned to the other compactor roller.
[0030] The present invention is subsequently described in detail
with reference to the appended figures. As shown in:
[0031] FIG. 1 a soil compactor with two compactor rollers usable
for carrying out a method for compacting asphalt material;
[0032] FIG. 2 a depiction to illustrate the transition between
different operating states of a motion generation arrangement
provided in assignment to a compactor roller depending on the
surroundings temperature;
[0033] FIG. 3 in one part a) the transition between different
operating states for a soil compactor with two vibratory rollers,
and in one part b) the transition between different operating
states in a soil compactor with one vibratory roller and one
oscillation roller;
[0034] FIG. 4 a depiction corresponding to FIG. 2 to illustrate the
transition between different operating states, depending on wind
speed.
[0035] In FIG. 1, a soil compactor, usable to compact asphalt
material A, is generally designated with 10. Soil compactor 10 in
the depicted embodiment is designed with a central compactor frame
12, on which an operator's station 13 is provided for an operator
operating soil compactor 10. A compactor roller 14, 16 is
respectively mounted to be rotatable about a respective roller axis
of rotation on a front end area and on a rear end area of central
compactor frame 12, wherein each of the two compactor rollers 14,
16 is pivotable with respect to central compactor frame 12 about a,
for example, substantially vertical steering axle for steering soil
compactor 10.
[0036] Soil compactor 10 advantageously has a motion generation
arrangement assigned to each of two compactor rollers 14, 16. This
type of motion generation arrangement may be designed as a
vibration arrangement in order to generate a force or acceleration
acting on respective compactor roller 14 or 16 substantially
orthogonal to its respective roller axis of rotation. This type of
vibration arrangement generally comprises an unbalanced mass
arrangement, arranged in the interior of respective compactor
roller 14 or 16 and rotatable about an unbalanced rotational axis,
with a center of mass eccentric to the unbalanced rotational axis,
which may advantageously correspond to the respective roller axis
of rotation. Due to this type of vibration arrangement and the
force or acceleration acting orthogonal to the roller axis of
rotation, a periodic impacting load is exerted on asphalt material
A to be compacted.
[0037] In one alternative embodiment, this type of motion
generation arrangement may be designed as an oscillation
arrangement, by means of which a periodically accelerating, back
and forth oscillation torque is generated [in] respective roller 14
or 16 about its roller axis of rotation. Due to this type of
periodic oscillation movement superimposed on the rotation of a
respective compactor roller 14, 16 during movement of soil
compactor 10 across asphalt material A to be compacted, a walking
or kneading effect is generated, leading to an increase in the
degree of compaction of asphalt material A. This type of
oscillation arrangement may comprise, for example, two unbalanced
mass arrangements with a center of mass, eccentric to the
respective unbalanced rotational axis and rotatable about
respective unbalanced rotational axes, wherein the two unbalanced
rotational axes are eccentric to the roller axis of rotation, for
example, lying diametrically opposite one another with respect to
the roller axis of rotation and parallel to the same.
[0038] Soil compactor 10 may comprise, for example, a vibration
arrangement assigned to each of two compactor rollers 14, 16. In
one alternative embodiment, soil compactor 10 may comprise, for
example a vibration arrangement assigned to one of two compactor
rollers 14, 16 and may comprise an oscillation arrangement assigned
to the other of two compactor rollers 14, 16.
[0039] In particular, if this type of motion generation arrangement
is designed as a vibration arrangement, then this may be operated
in different motion excitation operating states. It is assumed for
the subsequent description that this type of vibration arrangement
may be operated in two motion excitation operating states with
different energy inputs, which is advantageously achieved in that,
at a rotational speed of a respective unbalanced mass arrangement
assumed to be substantially constant, the mass, acting on or
combined with the center of mass, is switchable in the same. This
switching may be induced, for example, by changing the rotational
direction of the unbalanced mass arrangement and a relative
circumferential movement of two mass parts of the unbalanced mass
arrangement caused by this. Depending on the motion excitation
operating state, the vibratory roller in this type of vibration
arrangement may be operated with a larger excitation amplitude g or
with a smaller excitation amplitude k. If the motion generation
arrangement assigned to a compactor roller 14 or 16 is deactivated,
then compactor roller 14 or 16 functions in a static operating
state s, and thus compacts asphalt material A, traveled over by the
same, merely with the static load exerted on this asphalt material
A.
[0040] During spreading of asphalt material A, for example, during
road construction by means of one or more asphalt pavers 18, the
temperature of asphalt material A decreases in the area lying
behind asphalt paver 18 at increasing distance from asphalt paver
18. This means that areas of different distances from asphalt paver
18 have different temperatures. In FIG. 2, the decrease of the
asphalt temperature at increasing distance from asphalt paver 18 is
illustrated by a decreasing thickness of depicted asphalt material
A.
[0041] In order to be able to achieve a desired or optimal
compaction result during compaction of asphalt material A, spread
by asphalt paver 18, while taking into account, for example, a
predetermined compaction plan for a compaction process, one or more
soil compactors 10 work in different operating states in different
temperature ranges. Thus, for example, only static compacting is
used in an area directly following asphalt paver 18, in which
asphalt material A has a comparatively high temperature. This means
that, in this area, one or more motion generation arrangements,
provided in this type of soil compactor 10, are deactivated. If the
asphalt temperature drops below an upper threshold temperature O,
in at least one of compactor rollers 14, 16, one motion generation
arrangement assigned to the same may be activated, in order to
compact already somewhat cooled down asphalt material A not only
using the static load, but also by introducing energy generated by
a motion generation arrangement assigned to one of respective
compactor rollers 14, 16.
[0042] If the asphalt temperature drops below a lower threshold
temperature U, this transitions back into a static operating state
s, since further compaction of asphalt material A is no longer
achievable at an asphalt temperature lying below lower threshold
temperature U, even when operating a motion generation arrangement
and the energy input induced thereby, but instead there is a risk
that the structural integrity of the already compacted and cooled
down asphalt material A is damaged.
[0043] In an intermediate temperature range Z, lying between upper
threshold temperature O and lower threshold temperature U, the
motion generation arrangement assigned to at least one of compactor
rollers 14 or 16 is operated in soil compactor 10 in order to
achieve the desired compaction of asphalt material A in this
intermediate temperature range Z through the additional
introduction of energy. It may thereby be advantageous to work with
a larger energy input at a higher asphalt temperature, whereas
then, when the asphalt temperature has already decreased in
intermediate temperature range Z, it may be worked, for example,
with a lower energy input. In the previously described case, in
which the motion generation arrangement is a vibration arrangement,
which may be operated in two motion excitation operating states g,
k, with a larger energy input, thus a larger amplitude, and a
smaller energy input, thus a smaller amplitude, then the transition
between these two motion excitation operating states may be carried
out at an intermediate threshold temperature M. If the asphalt
temperature drops below this intermediate threshold temperature M,
then the motion excitation operating state is switched from motion
excitation operating state g with the larger amplitude to motion
operating state k with the smaller amplitude. If the asphalt
temperature also drops below lower threshold temperature U, the
motion generation arrangement is transitioned into static
compaction operation, in this case, a vibration arrangement is thus
deactivated.
[0044] The temperature of asphalt material A spread by asphalt
paver 18 depends strongly on surroundings parameters influencing
the cooling behavior of asphalt material A. One of the surroundings
parameters substantially influencing this cooling behavior is
surroundings temperature T. At a low surroundings temperature T,
asphalt material A cools down faster than at a higher surroundings
temperature T. Wind speed W also substantially influences the
cooling behavior of asphalt material A. A higher wind speed W leads
to a significantly stronger energy discharge, and thus to a faster
cooling down of asphalt material A, than a lower wind speed W.
[0045] By taking the surroundings parameter influencing this type
of cooling behavior of asphalt material A into account, the
different threshold temperatures O. M, U may be adjusted in order
to guarantee that sufficient time is available, above all to carry
out a compacting process with additional introduction of energy
into asphalt material A, thus with an activated motion generation
arrangement, for example, to be able to execute a compacting plan
with, for example, a plurality of traverses. This adjustment or
selection of different threshold temperatures O, M, U, depending on
surroundings parameters, is subsequently described in detail with
reference to FIGS. 2 to 4.
[0046] FIG. 2 shows the consideration of surroundings temperature T
as the parameter influencing the cooling behavior of asphalt
material A to be compacted. Three different surroundings
temperatures T.sub.H, T.sub.T and T.sub.M are depicted in FIG. 2.
T.sub.H is a state of a comparatively high surroundings temperature
T, for example, in the range from 30 to 40.degree. C. State T.sub.M
may correspond to an intermediate surroundings temperature T, for
example, in the range from 10 to 20.degree. C., while state T.sub.T
may correspond to a comparatively low surroundings temperature in
the range of less than 10.degree. C.
[0047] It is quite clear in FIG. 2 that upper threshold temperature
O, dropping below which triggers a transition from a static
compaction operation to a compaction operation with additional
energy input, thus a motion excitation operating state, is
increased at decreasing surroundings temperature T. This means
that, at a low surroundings temperature T, working with a larger
amplitude, for example, in motion excitation operating state g, is
begun at a higher asphalt temperature, that at a higher
surroundings temperature T. This leads to the fact that the
temperature window, which is available for the compaction operation
with additional energy input, is extended upward. Likewise, at a
decreasing surroundings temperature T, lower threshold temperature
U is displaced into lower temperatures. This means that, at a
decreasing surroundings temperature T, the transition to a static
compaction operation is delayed, which likewise leads to the fact
that the temperature window available for the operating state with
additional energy input is extended. Due to the extension of the
temperature window lying between threshold temperatures O and U at
decreasing surroundings temperature T, the faster cooling down of
asphalt material A at decreasing surroundings temperature T is
compensated, so that sufficient time is available, also at low
surroundings temperatures, in order to suitably compact asphalt
material A, for example, according to a predetermined compaction
plan. The risk, that due to a time available for this work process
being too short, which places an operator under time pressure, and
thus stress-caused operating errors may occur, may thus be
minimized or excluded.
[0048] It is further clear in FIG. 2 that intermediate threshold
temperature M is also decreased at decreasing surroundings
temperature T. This also means that, to carry out the compaction
operation with a larger energy input or larger amplitude, a larger
temperature window is available, thus compensating for a faster
cooling down, and thus motion excitation operating state g, with a
larger energy input, thus a larger amplitude, which is particularly
important for a suitable compaction of asphalt material A, may be
carried out in the predetermined measure.
[0049] FIG. 3a) illustrates predetermined values for upper
threshold temperature O, intermediate threshold temperature M, and
lower threshold temperature U for a soil compactor 10 with two
compactor rollers 14, 16 designed as vibratory rollers for
different surroundings temperatures or temperature ranges. In each
case, column v respectively shows the operating state to be set for
front compactor roller 14 and column h respectively shows the
operating state to be set for rear compactor roller 16. Three
layers, L1, L2, and L3, correspond to a three-layer structure, with
support layer L1 to be arranged below, binder layer L2 to be
arranged on support layer L1, and cover layer L3 to be arranged
over binder layer L2 and providing the upper side.
[0050] It is clear in FIG. 3a) that, at an asphalt temperature
lying above upper threshold temperature O, both compactor rollers
14, 16 are operated statically, thus, the motion generation
arrangements assigned to the same are deactivated, which is also
the case when the asphalt temperature lies below lower threshold
temperature U. At an asphalt temperature lying in intermediate
temperature range Z, thus between upper threshold temperature O and
lower threshold temperature U, two compactor rollers 14, 16 or the
motion generation arrangements respectively assigned to the same
are operated in motion excitation operating state g with a large
energy input, in motion excitation operating state k with a small
energy input, or statically, depending on whether the asphalt
temperature is above or below intermediate threshold temperature M,
and depending on which of three layers L1, L2, L3 is to be
compacted. It is also clear in FIG. 3a) that different threshold
temperatures O, M, and U are selected for different surroundings
temperatures T or ranges of surroundings temperature T, so that
upper threshold temperature O increases at decreasing surroundings
temperature T, while intermediate threshold temperature M and lower
threshold temperature U decrease at decreasing surroundings
temperature T.
[0051] FIG. 3b) correspondingly illustrates the selection of
different threshold temperatures O, M, and U for a soil compactor
10, in which, for example, a vibration arrangement is assigned to
front compactor roller 14, which is thus a vibratory roller, while
an oscillation arrangement is assigned to rear compactor roller 16,
which is thus an oscillation roller. The same temperature-dependent
tendency of different threshold temperatures O, M, and U is clear
in FIG. 3b). Further, it is also clear that the vibration
arrangement assigned to front compactor roller 14 may be operated
in different motion excitation operating states g and k, depending
on different layers L1, L2, or L3 to be compacted. The oscillation
arrangement assigned to rear compactor roller 16 is operated in
this example only in a motion excitation operating state o, and may
thus be either activated or deactivated. A switching of the
oscillation arrangement between motion excitation operating states
with different energy inputs is not provided in this exemplary
embodiment.
[0052] FIG. 4 illustrates the consideration of wind or of wind
speed W when setting different threshold temperatures O, M, U. Four
different wind states or wind speeds W.sub.0, W.sub.1, W.sub.2 and
W.sub.3 are depicted in FIG. 4. State W.sub.0 is thereby depicted
as a wind-free state, while states W.sub.1, W.sub.2 and W.sub.3
depict states with an increasing wind speed W. A high wind speed W
means a faster cooling down of asphalt material A and thus
influences its cooling behavior in a way similar to a low
surroundings temperature T. Correspondingly, at an increasing wind
speed W and thus an increasingly faster cooling down of asphalt
material A, upper threshold temperature O is increased in order to
transition earlier, that is, at higher temperatures, from static
compaction operation into a compaction operation with additional
energy input. In the example illustrated here of a soil compactor
10 with a compactor roller 14 or 16 with a vibration arrangement
assigned to the same, for example, motion excitation operating
state g with a larger energy input, thus a larger amplitude, may be
entered into upon exceeding the upper threshold temperature.
[0053] intermediate threshold temperature M, at which a switching
is carried out from motion excitation operating state g with a
large energy input to a motion excitation operating state k with a
small energy input, is displaced to lower temperatures at
increasing wind speed, so that the temperature window, available
for carrying out the compaction operation using motion excitation
operating state g with a large energy input, is a correspondingly
larger temperature window compensating for the faster cooling down.
Likewise, lower threshold temperature U, dropping below which
triggers the transition into static compaction operation s, is
displaced to lower temperatures at an increasing wind speed W.
[0054] The consideration of different parameters, to be take into
consideration in the cooling behavior or asphalt material A,
previously described with respect to FIGS. 2 to 4, may be combined
in particularly advantageous ways. Thus, both surroundings
temperature T and also wind speed W may be taken into consideration
in setting threshold values O, M, and U. For example, a base value
for respective threshold temperature O, M, or U may be respectively
selected when taking surroundings temperature T into consideration
on the basis of the tables illustrated in FIG. 3a) or 3b), which
base value may be corrected by taking wind speed W into
consideration, for example, it may be displaced or proportionally
changed by a respectively predetermined temperature amount,
depending on the wind speed. It is also possible to specify a base
value, taking wind speed W into consideration, and adjusting this
base value depending on the surroundings temperature, likewise the
specification of correction values, which depend on wind speed W or
surroundings temperature T and may then be used, for example, in
addition to the specification of a respective threshold
temperature.
[0055] The different values to be considered in the previously
described method, thus the asphalt temperature, surroundings
temperature T, and wind speed W, may be detected by suitable
sensors, known in the prior art, and passed to a control unit in
the form of respective detection signals. For example, the asphalt
temperature may be detected by optical sensors, e.g., infrared
sensors, while the surroundings temperature may be detected by a
conventional temperature sensor, and the wind speed may be detected
by a windmill with a rotational speed sensor assigned to the same.
In the control unit, which may be designed with a microprocessor
with a work program stored or executed therein, these variables may
be processed in the previously described way, and automatically
used to predetermine the suitable operating state for compactor
rollers 14, 16 or the motion generation arrangements assigned to
the same, depending on the temperature that asphalt material A
currently has, which is to be respectively traveled over by soil
compactor 10. The opportunity may thereby be provided for an
operator to intervene in this automatic operation, in that the
threshold temperatures, specified for the respectively prevailing
surroundings conditions, may be additionally displaced, in a
limited temperature range, by the operator in the direction of
higher or lower temperatures.
[0056] Reference is further made to the fact that the previously
described method may also be carried out when, for example, a
vibration arrangement is operable in more than two different motion
excitation operating states, so that multiple intermediate
threshold temperatures may lie between the upper threshold
temperature and the lower threshold temperature, which each depict
a transition between motion excitation operating states with
different energy inputs. This type of motion generation arrangement
may also be designed so that no discrete, thus step-wise change of
the energy input occurs during the transition between different
motion excitation operating states, but instead a continuously
variable adjustment is achieved of the energy introduced into a
respective compactor roller and thus into the asphalt material. For
example, this type of motion generation arrangement may be operated
so that, upon dropping below the upper threshold temperature, it
transitions from the previously carried out static compaction
operation into a compaction operation with a maximum energy input,
thus for example, a maximum excitation amplitude in a vibration
arrangement or oscillation arrangement, and at a decreasing asphalt
temperature, a linearly declining energy input is set, until a
state of minimum energy input is reached upon dropping below the
lower threshold temperature. This state of minimum energy input
may, for example, correspond to a state of a deactivated motion
generation arrangement, or may correspond to a state with a
non-zero energy input.
* * * * *