WO2009049821A1

WO2009049821A1 - Soil-tamping device having adaptive drive regulation

Info

Publication number: WO2009049821A1
Application number: PCT/EP2008/008536
Authority: WO
Inventors: Michael Steffen
Original assignee: Wacker Neuson Se
Priority date: 2007-10-12
Filing date: 2008-10-09
Publication date: 2009-04-23
Also published as: DE102007048980A1; EP2212477B1; EP2212477A1; CN101821456A; US20100284743A1

Abstract

A tamping device comprises a drive motor (4) which, via a spring mechanism (8), drives a soil contact element (3) for compacting the soil. A detection device (11, 12) records the speed of rotation of the drive motor (4). An evaluation device (13) evaluates the dynamic response of the speed of rotation and recognizes an aperiodic response. A control device prompts a change in the speed of rotation of the motor if an aperiodic response has been recognized.

Description

description

Ground ramming device with adaptive drive control

The invention relates to a ramming device for soil compaction.

Such a tamping device, hereinafter also referred to as rammer, is known in various embodiments, such. B. from DE 44 45 188 Al or DE 197 39 743 A l.

The basic principle is based on the fact that a rotational movement of a drive motor is converted into an oscillating linear motion, which via a spring system to a ground contact element, for. B. a padfoot is transmitted. The rammer has an upper mass, which u.a. the drive motor, a part of a crank mechanism, housing elements and bearings. A lower mass is movably coupled to the upper mass via a spring device, which has the ground contact element for soil compaction. The crank mechanism converts the rotational movement of the drive motor into a linear reciprocating motion, which is transmitted by the spring device, in particular via a two-sided spring system, to the lower mass and thus to the ground contact element. An example of the spring device is shown in DE 197 39 743 Al.

The movement of the crank mechanism imposes a periodic, oscillating movement on the ground contact element. This periodic movement is also ideally maintained during soil compaction. Then the soil can be compacted very effectively.

However, it has been found that rammers can usually only be optimally designed for a specific soil structure or rigidity, so that with some soil structures the periodic movement can be achieved at least approximately and thus an effective compaction can be realized, while in other soils of a no longer periodic behavior can be condensed only limited. So it comes z. Example, before a rammer on uncompressed, compaction-willing soil uniformly compacts the soil, while he falls with increasing soil density "out of step". This can be z. As a result, two strokes of the padfoot are followed by an idle blow because the spring-mass system formed by the rammer and the ground is no longer in synchronization. A blanking occurs especially when such a large recoil force acts on the lower mass in the previously effective impact that the entire rammer so is printed high above the ground that in the subsequent cycle, the ground contact plate can no longer reach the ground

In an asynchronous, aperiodic operation, the passive system (O bermasse, Fuhrungshandgπff) reacts with high amplitudes, which can lead to the loss of controllability of the rammer. The operator is burdened with the leadership of the rammer high, while the device only with low Effectiveness works The hand-arm accelerations reach high values, which reduces the useful life of the device

FIGS. 5 and 6 show examples of the synchronous, periodic operation (FIG. 5) and an asynchronous, aperiodic operation (FIG. 6) of a ramming machine. In each case, the amphetics courses are over time for the padfoot belonging to the lower mass, the body belonging to the upper mass and The harmonic movements of foot, crankcase and handle are clearly visible in the periodic operation shown in Figure 5, while the asynchronous operation shown in Figure 6 leads to a stochastic movement behavior of the components of the rammer

The invention has for its object to provide a tamping device with a gleichmaßiges, periodic work is possible even with different soil structures

The object is achieved erfmdungsgemaß by tamping devices according to claims 1 and 3 Advantageous embodiments of the invention are defined in the dependent claims

In a known manner, a tamping device has a drive motor, an upper mass receiving the drive motor, a lower mass movably coupled to the upper mass via a spring device, which comprises a ground contact element for ground compaction, and a movement transmission device for transmitting a drive motion from the drive motor and generating one Furthermore, a detection device is provided for detecting a measurement parameter for the dynamic behavior of at least one component of the tamping device. An evaluation device serves to evaluate the dynamic behavior and to detect an aperiodic behavior. Einπchtung can be displayed that the Aperiodisches behavior is detected by the evaluation

As a component of the stamping device, various subregions and components are conceivable, such as the motor shaft, a crankshaft belonging to the crank mechanism, connecting rod, upper mass housing, padfoot with ground contact element, guide handle, etc

Thus, during the operation of the tamping device, a measuring parameter is permanently recorded which serves as a criterion for the dynamic behavior of the relevant component, but possibly also of the entire tamping device. Ideally, the measuring parameter should correspond to the periodic excitation by the movement transmission device, ie, for example, a crank drive However, if the evaluation device determines that the measurement parameter and thus the actual dynamic behavior deviate from a substantially uniform, eg sinusoidal, periodic behavior, this is considered as a criterion for an aperiodic behavior. It is concluded that the operation The rammer is then informed about the display device that an aperiodic behavior is present

Static or dynamic rules can be stored in the evaluation device for defining recommendations for action for the user, in particular as to how he should change the rotational speed of the drive motor in order to reduce aperiodic behavior. The evaluation device is capable of statically or dynamically depending on a suitable action recommendation The operator can be informed in this way to increase or decrease the speed in order to achieve at least approximately periodic behavior of the rammer and thus a synchronous interaction between rammer and ground again

In one variant, the tamping device has a control device for changing at least one dynamic parameter of at least one of the components of the tamping device if an aperiodic behavior is detected by the evaluation device. It is not necessary for the operator to be informed about the aperiodic behavior and control measures how, for example, a change in the speed, takes hold. automatically automatically takes appropriate measures to achieve a periodic, synchronous behavior again in the case of an aperiodic behavior. If the control device carries out these measures continuously or with very short time intervals, the operator will not notice this at all

Of course, it is also possible to provide a display device in this variant in order to inform the operator that an aperiodic behavior is detected by the evaluation device. The change of the dynamic parameter or execution of the control measures can, however, also take place without the operator The display device is then not required

The vibration behavior of the rammer can be determined by a suitable measurement parameter which is selected from the group of rotational speed of the drive motor, load impacts on a motor shaft of the drive motor, speed of the motion transmission device, movement behavior of the respective monitored component, relative movement between the upper mass and the lower mass, acceleration of the respective Component, acceleration of the upper mass, acceleration of the lower mass, acceleration of a guide handle attached to the upper mass, rotational angle between the Fuhrungshandgπff and the upper mass

The load impacts on the motor shaft of the drive motor cause a change in the engine speed, which can be detected relatively easily. The bumps result from a pulsating power consumption of the ramming system and lead to a periodic change in the engine speed The speed changes are with regular force exchange of the padfoot (ground contact element) As the engine speed changes periodically, the evaluation assumes a proper operation If, however, occur deviations from the periodic change, so therefore aperiodic behavior is detected, the appropriate measures are taken

In addition or as an alternative to the rotational speed, it is also possible to detect and evaluate the movement behavior or the acceleration of a respectively suitable component of the rammer. In addition, it may be expedient to also detect and evaluate the angle of rotation of the guide handle relative to the upper mass In a simple embodiment, it is sufficient to detect only one measurement parameter. Depending on the desired accuracy, however, it may also be expedient to evaluate a plurality of measurement parameters, for example also by a plurality of sensors (speed sensor, acceleration sensor, etc.) in order to obtain the most accurate possible image of the movement behavior to get the rammer

The dynamic parameter is selected from the group speed of the drive motor, torque of the drive motor, spring stiffness of the spring device between see upper mass and lower mass, and damping properties of a arranged between the upper mass and lower mass damping device

A change in the speed of the drive motor will be the easiest way to influence the dynamic behavior of the tamping device. The speed can either be changed manually by the operator if the display device gives him a corresponding recommendation for action Drive motor change in a suitable manner when aperiodisches behavior is detected

Alternatively or additionally, the spring stiffness of the upper mass and the lower mass coupling spring device can be changed Corresponding facilities for this are known from many areas of engineering, eg from the automotive industry. It is also possible to intervene in the steamer's steaming system In general, the spring device also damping properties, which can be changed z by controllable active Dampfungsglieder between the upper mass and the lower mass

Likewise, alternatively or additionally, it is possible to adjust the amplitude or amplitude of the ground contact element, ie in particular the jumping height of the padfoot. This is possible, for example, by adjusting the transmission behavior of the movement transmission device. For example, the crank radius of the tamping drive can be adjusted in order to adjust the stroke for to change the excitation of the spring system used for the motion transmission

Likewise, it is possible to change the oscillation frequency of the ground contact element. For example, the transmission ratio between the drive motor and the movement transmission device can be adjusted, so that a frequency change of the stomp motion takes place at the same engine speed. Of course, both the engine speed and the transmission ratio can be changed to change the overall vibration frequency.

The possibilities mentioned for determining the dynamic parameter can be taken individually or in combination. It is possible that the measures can work in the same direction, but also in the opposite direction. So it is e.g. conceivable that the crank radius is reduced and at the same time the engine speed or stamping frequency is increased

An aperiodic behavior can be detected, in particular, if the correspondingly provided measurement parameter deviates from an ideal periodic behavior beyond a predetermined extent. The ideal periodic behavior should be set in such a way that it can be easily achieved in the normal, efficient operation of the rammer. Deviations within the scope of the given measure are permissible for this ideal periodic behavior. Only when the tolerance range is exceeded, an aperiodic behavior is assumed, so that the appropriate measures are taken.

In one embodiment, the drive motor is a gasoline engine, wherein the variable speed as a dynamic parameter is a nominal or limit speed.

To regulate the nominal or limit speed in gasoline engines mechanical and electronic speed controllers are used, which from the engine speed an effect on performance and speed-determining assemblies (carburetor throttle or Zundkennfeld in internal combustion engines) generate so as not to increase the engine speed above the predetermined limit speed let or keep at the specified rated speed. Depending on the load, the opening of the carburetor throttle, the ignition angle and the duty cycle of the ignition is adjusted so that the speed control difference is minimal.

Analogously, by the way, the drive motor can also be an electric motor, which, for example. having an electronic speed controller in the form of a voltage or frequency controller.

The above-mentioned in connection with the gasoline engine controller in conventional rammer drive motors work statically. Your map is determined by design of the Fhehgewichte, the springs, etc. or by specifications of Zundkennfeldes and serves to maintain a certain speed. A manual or adaptive variation of the level of the regulated limit speed (and thus the tπebsfrequenz the rammer) in the prior art, neither manually nor electronically available

In contrast, in the mentioned embodiment, the limit speed can be changed to thereby influence the drive frequency of the rammer

The gasoline engine may include a map-controlled ignition device, wherein the speed of the gasoline engine by the ignition device by means of a variation of a Zundzeitpunkts is to be kept constant at the value of the limit speed constant

The control device can be designed such that upon detection of aperiodic behavior of the motor shaft, a change in the rotational speed of the drive motor is effected according to predetermined rules

The rules can be stored in the evaluation device, for example in the form of specifications which prescribe a specific control measure when the aperiodic behavior occurs, as well as through characteristic curves, characteristic diagrams and / or predetermined operating points on characteristic curves or characteristic diagrams

Thus, if an aperiodic behavior has been recognized, are to be taken by the control device in this evaluation, this can mean a slow linear increase or decrease of the limit speed of the drive motor Likewise, specific operating points on the respectively associated characteristic curve or It is possible, for example, to specify, in addition to the normal operating point, three to five alternative operating points, which are set in sequence by the control device in order to test whether the oscillation behavior It has been found that in most cases an improvement in the periodic tampering behavior can be achieved

These and other advantages and features of the invention will be explained in more detail below by way of example with the aid of the accompanying figures

1 shows an example of a rammer according to the invention,

FIG. 2 is a mechanical equivalent image of the rammer of FIG. 1; FIG. 3 is a schematic representation of the structure of the stamping device;

4 shows a two-dimensional characteristic diagram for a gasoline engine tamper;

5 shows the vibration behavior of components of a rammer during synchronous-periodic operation; and

Fig. 6 shows the movement behavior of the components in asynchronous aperiodic operation.

Fig. 1 shows a typical rammer in side view, with an upper mass 1 and a lower mass 2, which comprises a pestle foot 3 serving as a ground contact element. To the upper mass 1 includes a drive motor 4, which is designed as a gasoline engine. In addition, a guide handle 5 is elastically attached to the upper mass 1, on which the operator can guide the rammer and carries a fuel tank 6.

Inside a belonging to the upper mass 1 housing 7 is arranged in a known manner, a crank mechanism which converts the rotational movement of the drive motor 4 in an oscillating linear motion, via a spring system, not shown, per se known spring system to the lower mass 2 and finally to the padfoot third is transmitted.

Fig. 2 shows the rammer in a simplified schematic representation, where there is also a the upper mass 1 with the lower mass 2 coupling spring device 8 is located.

In Fig. 3, the rammer is shown again simplified in the form of the drive motor 4, which drives a connecting rod 10 via a crankshaft 9, whose linear reciprocating motion is transmitted via the spring means 8 to the lower mass 2.

The rotational movement or rotational speed of the crankshaft 9, which in the example shown is at the same time a motor shaft 4a of the drive motor 4, is detected by a rotational speed sensor 11. Of course, embodiments are also conceivable in which the motor shaft 4 a of the drive motor 4 initially drives a transmission which is finally coupled to the crankshaft 9. Likewise, the information about the speed behavior can also be obtained by monitoring the ignition etc. Thus, a control processor of the ignition system of the drive motor 4 can be used to obtain information about the speed behavior of the motor shaft 4a or the crankshaft 9 The aim is to detect and observe the change in the speed in the drive train due to the load impacts occurring when working with the rammer

It is therefore not absolutely necessary to provide a separate speed sensor 11

The corresponding measurement signal from the rotational speed sensor 11 or alternative information is supplied to a detection device 12 which detects the dynamic behavior of the crankshaft 9 or the motor shaft 4a

Corresponding information is transmitted by the detection device 12 to an evaluation device 13, which recognizes an aperiodic behavior by evaluating the dynamic behavior. If the evaluation device 13 recognizes the aperiodic behavior of the rammer as shown by way of example in FIG. 6, it can display this via a display device 14 they pass on the information to a control device 15 which controls a ignition system 16 of the drive motor 4 in accordance with predetermined rules in order to change the rotational speed. By changing the rotational speed, a changed dynamic behavior of the rammer is achieved, which in the ideal case results in an improvement of the periodic behavior. so that a movement behavior shown by way of example in FIG. 5 can be achieved

Instead of the control device 15, it is also possible merely to inform the operator by the display device 14 that an aperiodic behavior has been determined. If necessary, the operator can be given action recommendations on what measures he should take to reduce the aperiodic behavior two LEDs labeled "plus" and "minus" encourage the operator to increase or decrease the speed by operating the throttle lever

FIG. 4 shows various characteristic curves or two-dimensional characteristic diagrams which define the ignition time as a function of the engine speed. In a range from 0 to approximately 3,700 rpm, the engine maps are designed identically in the operating range which is important for operation between 3,700 and 5,000 rpm four maps are spread by corresponding characteristics and thus define a different behavior.

The evaluation device 13 or the control device 15 either selects predetermined operating points within a characteristic field or for different characteristic fields, which can be set upon detection of an aperiodic behavior. Optionally, by automatically "trying out" different operating points or by tracing the characteristics, the dynamic behavior of the rammer can be changed until an improvement in the periodic behavior is achieved.

An ignition map controlled on this basis is suitable e.g. for two-stroke engines in which the limit speed of the engine is maintained by varying the ignition timing. The sole input variable, the period of the mounted on the crankshaft fan wheel is used with magnet, from the magneto electric signals are obtained, which are used as a criterion for the speed and replace the signal of a speed sensor 1 1, so that can be dispensed with.

From the electric signals obtained from the magneto ignition engine speed and the current angular position of the crankshaft 9 is obtained relative to the top dead center of a piston in the engine 4. In a suitable two-dimensional characteristic diagram according to FIG. 4, the angle specification of the ignition process takes place relative to the top dead center of the engine 4.

With the help of the adaptive influence on the drive speed of the drive motor 4 of the rammer an adaptation of the rammer is effected to its environment. This leads to optimal work results and a smooth running even on more compacted soils. The hand-arm vibrations are thereby reduced while the maneuverability of the rammer is improved even in cohesive soils.

Claims

claims

1 . Stamper, with a drive motor (4); a drive motor (4) receiving the upper mass (1); a lower mass (2) movably coupled to the upper mass (1) via a spring device (8) and having a ground contact element (3) for soil compaction; a motion transmission means (9) for transmitting a drive motion from the drive motor (4) and generating a periodic motion of the ground contact element (3); - Detection means (1 1, 12) for detecting a measurement parameter for the dynamic behavior of at least one component of the tamping device; an evaluation device (13) for evaluating the dynamic behavior and recognizing an aperiodic behavior; and with - a display device (14) for indicating that an aperiodic behavior is detected by the evaluation device (13).

2. tamping device according to claim 1, characterized in that in the evaluation device (13) rules are deposited, for defining recommendations for action for a user, how to change the speed of the drive motor (4) to reduce the aperiodic behavior; a recommendation for action is selected by the evaluation device (13) as a function of the recognized aperiodic behavior; and that the selected action recommendation is displayed by the display device (14).

3. Stamper, with a drive motor (4); a drive motor (4) receiving the upper mass (1); - One with the upper mass (1) via a spring means (8) movably coupled lower mass (2) having a ground contact element (3) for soil compaction; a movement transmission device (9) for transmitting a drive movement from the drive motor (4) and generating a periodic movement of the ground contact element (3); a detection device (1 1, 12) for detecting a measurement parameter for the dynamic behavior of at least one component of the stamping device; an evaluation device (13) for evaluating the dynamic behavior and recognizing an aperiodic behavior; and with a control device (15) for changing at least one dynamic parameter of at least one of the components of the tamping device if an aperiodic behavior is detected by the evaluation device (13).

4. tamping device according to claim 3, characterized by a display device (14) for indicating that an aperiodic behavior is detected by the evaluation device (13).

5. tamping device according to one of claims 1 to 4, characterized in that the measurement parameter is selected from the group

Rotational speed of the drive motor (4);

Load impacts on a motor shaft (4a) of the drive motor (4);

Rotational speed of the movement transmission device (9); - movement behavior of the component concerned;

Relative movement between upper mass (1) and lower mass (2);

Acceleration of the component concerned;

Acceleration of the upper mass (1);

Acceleration of the lower mass (2); Acceleration of a guide handle (5) attached to the upper mass (1);

Angle of rotation between the guide handle (5) and the upper mass (1).

6. tamping device according to one of claims 1 to 5, characterized in that the dynamic parameter is selected from the group

Rotational speed of the drive motor (4);

Torque of the drive motor (4);

Spring stiffness of the spring device (8) between the upper mass (1) and lower mass (2); Damping properties of a damping device arranged between upper mass (1) and lower mass (2);

Amplitude of the ground contact element (3);

Oscillation frequency of the ground contact element (3).

7. stamping device according to one of claims 1 to 6, characterized in that an aperiodic behavior is detected when the measurement parameter deviates beyond a predetermined amount of an ideal periodic behavior.

8. tamping device according to one of claims 1 to 7, characterized in that the drive motor (4) is a gasoline engine; and that the variable speed that can be changed as a dynamic parameter is a nominal or limit speed.

9. tamping device according to claim 8, characterized in that the gasoline engine (4) comprises a map-controlled ignition device; and that - the speed of the gasoline engine (4) is to be kept constant by the ignition device by means of a variation of an ignition timing substantially at the value of the nominal or limit speed.

10. tamping device according to one of claims 1 to 9, characterized in that the control device (15} is designed such that upon detection of aperiodic behavior of the motor shaft (4a) causes a change in the speed of the drive motor (4) according to predetermined rules becomes.

1 1. Tamping device according to one of claims 1 to 10, characterized in that in the evaluation device (13) are deposited as rules:

Defaults to take a predetermined control action when the aperiodic behavior occurs; Characteristics; Maps; and / or - predetermined operating points on characteristic curves or maps.