EP2242590B1 - Unbalance exciter with one or more rotatable unbalances - Google Patents

Description

TECHNICAL AREA

The invention relates to a method for operating a machine with an unbalance exciter with one or more rotatable imbalances and a machine for carrying out the method according to the preambles of the independent claims.

STATE OF THE ART

Unbalance exciters with rotatable imbalances are used to generate time-varying excitation forces and are used in many areas of technology, for example in vibration conveyors, in vibrating screens, in compactors such as vibratory plates and vibratory rollers, in vibratory rams and in vibration-excited drilling and milling machines. The currently known monofrequent unbalance exciters, in which all imbalances rotate at the same speed, can basically be classified according to the excitation principle in the circular oscillator and the directional oscillator. Monofrequency circular oscillators produce an exciter force which is temporally variable only with regard to their direction. Monofrequency directional oscillators generate an exciter force, the amount of which changes with time along with its effective direction, such that seen over a full rotation of the imbalance masses two excitation force maxima are formed with opposite directions of action. While the circular oscillator manages with a rotating imbalance mass, the directional oscillator system requires at least two counter-rotating unbalanced masses. Since such unbalance exciters generate in each case in opposite directions of action the magnitude equal excitation force components that is with them when used in compactors and rams depending on whether work must be carried out in on-load operation or operation with temporary lifting of the tool from the work surface is permitted or desired.

In addition to the widespread monofrequency unbalance exciters and bifrequent unbalance exciters are known in which the time-varying excitation force is generated by superimposing the excitation force of a rotating at a basic speed first imbalance mass with the exciter force of a phase in phase with twice the speed rotating second imbalance mass. These unbalance exciters generate an exciter force with a single maximum force in a particular direction.

The documents SU 1 119 738 A . GB 1 439 455 . EP 0 411 349 A1 . DE 10 2005 009 095 A1 and US 2,309,172 disclose various types of multi-frequency unbalance exciters.

In practice, such bifrequent unbalance exciters have been proven in vibratory rams for sheet piles, where they can be generated with significantly greater ramming forces than comparable monofrequenten unbalance exciters. In other applications, however, especially in vibratory plates and vibratory rollers for soil and asphalt compaction, could be achieved with the known bifrequenten unbalance exciters only small improvements in compression performance over monofrequently energized Vessichtungsgeräten, which is why in the light of the much higher apparatus engineering effort to use such imbalance exciters in the Compaction technology has been largely dispensed with. Out EP 0 411 349 A1 is a soil compacting device with a bifrequenten unbalance exciter known.

PRESENTATION OF THE INVENTION

It turns the task, a method for operating a machine with a multi-frequency unbalance exciter and to provide a tool coupled to the unbalance exciter for vibrational excitation to act on a working surface, which achieves an optimization of the movement of the tool or the force exerted by the tool on the working surface and thus the working power of the machine.

Another object is to provide a machine for carrying out the method, which can be used to ensure that the machine is always operated in a good range or in the optimum range, i. always a relatively large or the maximum possible force can be transferred from the tool to the work surface.

These objects are achieved by the subject-matter of the independent claims.

Accordingly, a first aspect of the invention relates to a method for operating a machine comprising an unbalance exciter with one or more rotatable imbalance masses for generating a multi-frequency time-varying excitation force. For a single imbalance mass, it performs several superimposed rotations, e.g. can be rotationally rectified or rotationally opposite. In the case of a plurality of imbalance masses, these preferably each perform a single rotation, wherein it is provided that identical and / or opposite directions of rotation are used.

The excitation force is generated by the superposition of a basic exciter force, which is time-variable with a fundamental frequency, with one or more additional excitation forces which are time-variable with additional frequencies greater than the fundamental frequency. In this case, the unbalance exciter is designed such that the phase position between the time-varying basic excitation force and at least one of the time-varying auxiliary excitation forces is adjustable, preferably continuously.

Furthermore, the machine comprises a tool coupled to the unbalance exciter for the purpose of vibrational excitation for acting on a work surface.

According to the invention, the machine is operated in such a way that the tool, which is excited to vibrate with the unbalance exciter, acts as intended on a working surface, that is, performs a work as intended. In this case, the vibration response of the tool to the vibration excitation of the unbalance exciter and / or the course of the working surface reaction force is determined and compared this or with a desired target vibration response or a desired target working surface reaction force profile. How the vibration response or the working surface reaction force profile can be determined by measurement is known to the person skilled in the art and therefore need not be explained in more detail here.

Furthermore, the phase position between the time-varying basic excitation force and at least one of the time-varying additional excitation forces for changing the total excitation force and thus the vibration excitation is set such that a vibration response of the tool or a progression of the working surface reaction force results, which or which an improved and preferably the greatest possible match has the desired vibration response and the desired working surface reaction force curve.

In this way, an optimization of the movement of the tool or the force exerted by the tool on the work surface and thus the performance of the machine is achieved.

In a preferred embodiment of the method according to the invention, the phase position between the time-variable basic exciter force and at least one of the time-varying additional excitation forces is set or changed during operation of the machine, which enables interruption-free operation and preferably as automatic control intervention with a renewed one Comparison of the resulting vibration response or the resulting course of the working surface reaction force with the desired vibration response or the target working surface reaction force course takes place.

In a further preferred embodiment of the method, the phase position is adjusted such that a vibration response of the tool or a work surface reaction force curve results, at which or which the quotient of the maximum amplitude of the vibration response of the tool in the tool working direction and the maximum amplitude of the vibration response of the tool in the direction opposite to the tool working direction or the quotient of the maximum force of the work surface reaction force curve in the tool working direction and the maximum force of the work surface reaction force curve in the direction opposite to the tool working direction for given frequencies and amplitudes of the basic and additional exciter forces. In this way it can be ensured that the machine is operated at all times in a good or optimal range, that is always a relatively large or the maximum force is transmitted from the tool to the work surface.

In yet another preferred embodiment of the method, the phase position, the frequency and / or the amplitude of the basic exciter force and / or one or more of the additional excitation forces are preferably adjusted independently of one another such that a vibration response of the tool or a progression of the working surface reaction force results in which the maximum amplitude of the vibration response of the tool in a direction opposite to the pressing direction of the tool against the working surface or the maximum force of the working surface reaction force course in a direction opposite to the pressing direction of the tool on the working surface does not exceed a certain maximum value, for preventing a temporary loss of contact between the tool and the work surface when intended operation. This is, as already mentioned, particularly important in vibratory rollers for the compaction of asphalt, since these must be operated in on-load operation in order to reliably prevent a temporary lifting of the roller from the asphalt surface to be compacted.

In yet another preferred embodiment of the method, the resonant frequency of the machine-tool-work surface system during normal operation is determined in particular continuously and set the fundamental frequency in particular continuously to a frequency slightly above the determined resonant frequency, preferably to a frequency typically in the range between 105% and 130%, preferably between 110% and 120% of the determined resonant frequency. This results in the advantage that the fundamental frequency can be kept selectively in a range slightly above the resonance frequency, which allows a further performance optimization.

In yet another preferred embodiment of the method, the determination of the vibration response and / or the working surface reaction force curve and optionally the resonance frequency, the comparison with a desired target vibration response and / or a desired working surface reaction force curve and the adjustment of the phase position and optionally the Frequency and / or amplitude carried out automatically by means of a machine control, preferably continuously during operation of the machine. This can be ensured at any time operation with optimal operating parameters.

A second aspect of the invention relates to a machine comprising an unbalance exciter with one or more rotatable imbalance masses for generating a multi-frequency time-varying excitation force. In the case of a single imbalance mass, this performs several superimposed rotations which, for example, are rotationally rectified or rotationally opposite. In the case of a plurality of imbalance masses, these preferably each perform a single rotation, wherein it is provided that identical and / or opposite directions of rotation are used.

The excitation force is generated by the superposition of a basic exciter force, which is time-variable with a fundamental frequency, with one or more additional excitation forces which are time-variable with additional frequencies greater than the fundamental frequency. In this case, the unbalance exciter is designed such that the phase position between the time-varying basic exciter force and at least one of the time-varying additional excitation forces during operation is adjustable, preferably continuously.

Furthermore, the machine comprises a tool coupled to the unbalance exciter for the purpose of vibrational excitation for acting on a work surface.

Also, the machine comprises means for determining the vibration response of the tool to the vibration excitation of the unbalance exciter during normal operation of the machine and / or means for determining the course of the working surface reaction force during normal operation of the machine, which consists of a superposition of the from the vibration response of the tool and the oscillating mass of which results in the resulting movement force course of the tool with the exciter force profile of the exciter (s) and the static weight force of the machine

The means for determining the vibration response of the tool typically comprise acceleration sensors and a computer-aided processing unit which evaluates the signals supplied by the sensors. This makes it possible, the effects of a change in the phase angle between the basic excitation force and the at least one additional excitation force, which leads to a change in the resulting total exciter force leads to objectively assessing the vibration response of the tool, ie its course of motion, and thus to specifically influence this important operating parameter by deliberately adjusting the phase position.

In soil compaction machines, the working surface reaction force is also referred to as the soil reaction force.

The means for determining the progression of the work surface reaction force typically comprise acceleration sensors, positional sensors for rotating imbalances and a computer-aided processing unit which evaluates the signals supplied by the sensors. This makes it possible to objectively assess the effects of a change in the phase position between the basic excitation force and the at least one additional excitation force, which leads to a change in the resulting total excitation force on the force exerted by the tool on the work surface and thus optimize this force and thus the Performing work of the machine by targeted adjustment of the phase position.

In addition, the machine additionally comprises a machine controller, by means of which the phase position between the basic excitation force and the at least one additional excitation force is automatically and preferably continuously adjustable during operation such that a vibration response of the tool or a progression of the working surface reaction force results, in which or which the quotient of the maximum amplitude of the vibration response in the tool working direction and the maximum amplitude of the vibration response in the direction opposite to the tool working direction or the quotient of the maximum force of the course of the working surface reaction force in the tool working direction and the maximum force of the course of the working surface reaction force in the direction opposite tool working direction is maximum for given frequencies and amplitudes of the fundamental and auxiliary excitation forces.

This can ensure that the machine is always operated in a good range or in the optimum range, i. always a relatively large or the maximum possible force can be transferred from the tool to the work surface.

The machine is preferably a vibration-activated drilling machine, road milling machine or tunneling machine, a vibration rammer or a soil compaction machine, in particular a vibrating plate or a vibrating roller. In such machines, the advantages of the invention are particularly evident.

In a preferred embodiment of the machine, the unbalance exciter is designed such that at least one of the additional exciter forces is time-variable with an additional frequency corresponding to an integer multiple of the fundamental frequency, preferably with a frequency corresponding to twice the fundamental frequency. It has been shown that at integer frequency ratios the greatest performance gains are possible.

In yet another preferred embodiment of the machine, the unbalance exciter is designed in such a way that it has separate imbalance masses for generating the basic excitation force and the additional exciter forces, which each perform separate rotational movements. Such solutions are based on relatively simple and proven design principles and can also be retrofitted to existing multi-wave unbalance exciters.

In an alternative embodiment of the machine, the unbalance exciter is designed in such a way that, in order to generate the basic exciter force and at least one of the additional excitation forces, it has a common imbalance mass, which has at least two superimposed rotational movements performs. Such a construction method has as potential advantages a compact design, a simple phase position adjustment and minimum bearing speeds.

It may be preferred that the unbalance exciter has a counterweight, which reduces the imbalance generated by the imbalance mass in the rotation with the fundamental frequency and thus reduces the basic exciter force. This makes it possible to influence the relationship between the basic exciter force and the or the additional excitation forces by structural measures in many areas. In yet another preferred embodiment of the machine, the unbalance exciter is designed such that the fundamental frequency and / or the additional frequencies are preferably infinitely adjustable, preferably during operation. Usually, their ratio to each other is fixed, i. that a change in the fundamental frequency automatically leads to a corresponding change in the additional frequencies, as is the case with a forced coupling via gears. However, it is also intended to allow variable frequency ratios for specific applications.

In yet another preferred embodiment of the machine, the unbalance exciter is designed in such a way that the amplitude of the basic exciter force and / or the amplitude of one or more of the additional excitation forces are preferably infinitely adjustable, and to advantage during operation. Moreover, it is further preferred that the amplitudes are adjustable independently of the respective exciter frequency, e.g. by the center of gravity of the respective unbalanced mass is changed by the center of rotation or by superimposing equally fast and gleichsinning rotating imbalances.

Through these measures, a further optimization of the compaction performance is possible, in particular continuously and automatically during operation.

Further, it is advantageous that the machine comprises a machine control, by means of which the phase position, the frequency and / or the amplitude of the basic exciter force and / or one or more of the additional exciter forces are automatically and preferably continuously adjustable during operation such that a vibration response of the tool, or a progression of the work surface reaction force, yields at or the maximum amplitude of the vibrational response in a direction opposite to the pressing direction of the tool on the work surface or the maximum force of the work surface reaction force path in a direction opposite to the pressing direction of the tool against the work surface does not exceed a certain maximum value to prevent temporary loss of contact between the tool and the work surface during normal operation. This is particularly important in vibratory rollers for the compaction of asphalt, which must be operated in on-load operation, since a temporary lifting of the roller from the asphalt surface to be compacted would lead to poor surface quality (chatter marks), which should be avoided.

In yet another preferred embodiment, the machine also has means for in particular continuous determination of the resonance frequency of the machine-tool-work surface system during normal operation. These means typically comprise acceleration sensors, sensors for position detection of the pathogen (s) and a computer-aided processing unit which evaluates the signals supplied by the sensors and are preferably together with means for determining the vibration response of the tool and / or for determining the course of the working surface. Reaction force formed.

It is further preferred that the machine further comprises a machine control, with which the fundamental frequency automatically and preferably continuously is adjustable during operation to a frequency slightly above the determined resonant frequency, preferably to a frequency in the range between 105% and 130%, more preferably between 110% and 120% of the determined resonant frequency. This results in the advantage that the fundamental frequency can be kept continuously in a range slightly above the resonance frequency, which enables further performance optimization.

BRIEF DESCRIPTION OF THE DRAWINGS

• die Figuren 1 und 2 zwei grundlegende Konstruktionsprinzipien für Unwuchterreger;
• Fig. 3 eine perspektivische Prinzipdarstellung eines Unwuchterregers gemäss dem in Fig. 2 gezeigten Konstruktionsprinzips;
• Fig. 4 eine Seitenansicht einer erfindungsgemässen Vibrationswalze;
• Fig. 5 eine perspektivische Draufsicht auf den Unwuchterreger der Vibrationswalze aus Fig. 4;
• Fig. 6 einen Längsschnitt durch den Unwuchterreger aus Fig. 5;
• Fig. 7 eine Prinzipdarstellung der Phasenverstellung des Unwuchterregers aus den Figuren 5 und 6;
• die Figuren 8a bis 8d die Position der rotierenden Unwuchten und den Verlauf der Erregerkraft des Unwuchterregers, die Schwingungsantwort der Walzen sowie den Verlauf der Bodenreaktionskraft beim schwingungsantwortoptimierten Betrieb der Grabenwalze aus Fig. 4;
• die Figuren 9a bis 9d die Phasenlage der rotierenden Unwuchten und den Verlauf der Erregerkraft des Unwuchterregers, die Schwingungsantwort der Walzen sowie den Verlauf der Bodenreaktionskraft bei einem bodenreaktionskraftoptimierten Betrieb der Grabenwalze aus Fig. 4;
• Fig. 10 eine perspektivische Draufsicht auf einen Unwuchterreger gemäss der Prinzipdarstellung in Fig. 3;
• die Figuren 11a und 11b die Position der Unwuchtmasse des Unwuchterregers aus Fig. 10 in verschiedenen Winkelpositionen der Grundrotation bei zwei verschiedenen Phasenlagen; und
• Fig. 12 eine Draufsicht auf das Unterteil einer mit zwei Unwuchterregern gemäss Fig. 10 ausgerüsteten Vibrationsplatte.

Further embodiments, advantages and applications of the invention will become apparent from the dependent claims and from the following description with reference to FIGS. Showing:

• the Figures 1 and 2 two basic design principles for unbalance exciters;
• Fig. 3 a perspective schematic representation of an imbalance exciter according to the in Fig. 2 shown construction principle;
• Fig. 4 a side view of an inventive vibration roller;
• Fig. 5 a perspective top view of the unbalance exciter of the vibratory roller Fig. 4 ;
• Fig. 6 a longitudinal section through the unbalance exciter Fig. 5 ;
• Fig. 7 a schematic diagram of the phase adjustment of the unbalance exciter from the Figures 5 and 6 ;
• the FIGS. 8a to 8d the position of the rotating imbalances and the course of the exciter force of the unbalance exciter, the vibration response of the rollers and the course of the ground reaction force in the vibration-response optimized operation of the trench roller Fig. 4 ;
• the FIGS. 9a to 9d the phase of the rotating imbalances and the course of the exciter force of the unbalance exciter, the vibration response of the rollers and the course of the floor reaction force in a ground reaction force optimized operation of the trench roller Fig. 4 ;
• Fig. 10 a perspective plan view of an unbalance exciter according to the schematic diagram in Fig. 3 ;
• the Figures 11a and 11b the position of the imbalance mass of the unbalance exciter Fig. 10 in different angular positions of the basic rotation at two different phase angles; and
• Fig. 12 a plan view of the lower part of a with two unbalance exciters according Fig. 10 equipped vibration plate.

WAYS FOR CARRYING OUT THE INVENTION

Two basic design principles for unbalance exciters for a machine according to the invention are described in US Pat Figures 1 and 2 shown in perspective.

This in Fig. 1 The operating principle shown is based on the use of two rotating shafts 1, 2, each carrying an imbalance weight 3 and synchronized about parallel axes of rotation r1, r2 around, for example via a toothed belt or a toothed belt 4, are driven at different speeds f1, f2. In this case, the phase position between the two rotating shafts 1, 2 is adjustable, for example via a differential gear fifth

This in Fig. 2 The operating principle shown is based on the use of a single guided mass 3, which performs two superimposed rotations. The mass 3 is rotated at a first rotational speed f1 spaced around a first rotational axis r1, simultaneously rotating at a second rotational speed f2, which is greater than and synchronized with the first rotational speed f1, about a second rotational axis r2, which in turn is rotated rotated at the first rotational speed f1 and at a fixed distance about the first rotational axis r1. Due to the second superimposed rotation, the distance changes the mass 3 to the first axis of rotation r1 running. The rotation about the second axis of rotation r2 is caused by the fact that a component carrying the mass 3 and rotatable about the second axis of rotation r2 with a toothed wheel 6 engages with a fixed toothed wheel 7 arranged concentrically with the first axis of rotation r1 and unrolls on its outer circumference. The phase position between the first and the second rotation can be changed by rotating the gear 7 concentric with the first axis of rotation r1.

Fig. 3 shows a perspective schematic representation of a further developed unbalance exciter according to the in Fig. 2 shown construction principle. As can be seen, the unbalance exciter on a crankshaft-like main body 8 which is rotatably mounted about two end-mounted bearing pin 10 about a first axis of rotation r1 and connected to a drive motor 9, with which it is drivable at a first speed f1. The crank pin is formed by a shaft 11 which carries an imbalance weight 3. The shaft 11 is rotatably supported at its ends about a second axis of rotation r2. At one end, the shaft 11 has a projection with a pinion 6, which runs on the outer circumference of a fixed and concentric with the rotation axis r1 of the main body 8 gear 7. As can be seen, upon rotation of the main body 8 about the first axis of rotation r1, the shaft 11 with the imbalance mass 3 attached thereto is rotated at a fixed distance about the axis of rotation r1. In this case, due to the running of the pinion 6 on the circumference of the gear 7, the shaft 11 is simultaneously rotated about the second axis of rotation r2, so that the imbalance weight 3 performs a movement of two superimposed rotations. As a result of the different circumferences of pinion gear 6 and 7 shaft 11 rotates here with a speed f2, which is greater than the input speed f1 of the main body 8. To adjust the phase angle between the two Rotations about the axes of rotation r1, r2 around the gear 7 by means of an actuating lever 12 and an associated drive, such as a hydraulic cylinder 13, around its center and thus around the first axis of rotation r1 around a certain angle α are rotated.

Fig. 4 shows a side view of a trench roller according to the invention with an unbalance exciter, which according to the construction principle Fig. 1 realized. The trench roller consists of an undercarriage 14 with the rollers 15 and the unbalance exciter 16 and a superstructure 17 with the drive motor (not shown), which is isolated in terms of vibration with respect to the undercarriage.

Fig. 5 shows a perspective top view of the unbalance exciter of the trench roller Fig. 4 , The unbalance exciter 16 has two imbalance waves (not visible) arranged one above the other, which are respectively rotated about their own axes of rotation r1, r2. At one end of the unbalance exciter 16, a hydraulic motor 9 is arranged, with which the lower imbalance shaft with the fundamental frequency f1 can be rotated about the rotation axis r1.

A longitudinal section through the unbalance exciter Fig. 5 is in Fig. 6 shown. As can be seen here, the two unbalanced shafts 1, 2 of the unbalance exciter 16, which carry the imbalance masses 3, rotatably coupled to each other via a toothed belt transmission comprising a lower toothed belt pulley 18, an upper toothed belt pulley 19 and a toothed belt 4, such that the upper unbalanced shaft 2 with rotation of the lower imbalance shaft 1 with the fundamental frequency f1 zwangsssynchron and in the same direction with a frequency f2, which corresponds to twice the fundamental frequency f1, is driven.

As in synopsis with Fig. 7 can be seen, which shows the principle of the toothed belt coupling between the two unbalanced shafts 1, 2 greatly simplified, the phase position of the rotations f1, f2 of the two shafts 1, 2 can be adjusted to each other that an arrangement of two auxiliary pulleys 28a, 28b, their bearings are interconnected by a bridge 29, in a direction V transverse to a straight line through the centers of rotation of the lower 18 and the upper toothed belt pulley 19 by means of a drive, for example a hydraulic cylinder 13, is moved. By this displacement, the ratio of the free timing belt length between the upper and lower timing pulleys 18, 19 on the load side (side where the auxiliary pulley 28b engages the timing belt 4) changes to the free timing belt length between the lower and upper timing pulleys 18, 19 on the load-free side (side on which the auxiliary pulley 28a engages the toothed belt 4), so that the lower and the upper pulley 18, 19 and thus the unbalanced shafts 1, 2 are rotated relative to each other. In order for the toothed belt 4 to form the largest possible angle of wrap on the lower and upper pulleys 18, 19, which is desirable for keeping the tooth load as low as possible, pulleys 30 are additionally provided here, which can also serve as tension rollers. Likewise, however, it is also provided to form the bridge 29 as a clamping element, which in operation additionally pushes the two auxiliary pulleys away from one another and against the toothed belt 4 with a specific prestressing force.

Fig. 8a shows the upper and the lower unbalance shaft of the unbalance exciter from the Figures 5 and 6 during rotation with a first phase position to each other. As can be seen, the imbalance masses of the two unbalanced shafts 1, 2 in the illustrated situation have a twist angle φ of 105 ° with respect to one another. In this phase position, the unbalanced shafts 1, 2 generate the in Fig. 8b shown exciter force curves (excitation force Ferr in kN over the time t shown), which together give the total exciter force curve (not shown). In accordance with the operation of the trench roller according to Fig. 4 with this unbalance exciter on sandy soil resulting vibration response of the rollers (oscillation amplitude the rollers Amp in mm over the time t shown) is in Fig. 8c and the resulting progression of the floor reaction force (floor reaction force Frea in kN over time t) in FIG Fig. 8d ,

As can be seen, results in this phase on sandy soil an oscillation response of the rollers 15, in which the quotient of the maximum amplitude Amp of the vibration response of the rollers in the working direction (in this direction of gravity) to the maximum amplitude Amp of the vibration response of the rollers in the direction opposite Working direction is maximum. It is therefore a vibration-optimized operation of the trench roller, wherein in the present case, as from Fig. 8d shows a Bodenreaktionskraftverlauf results, which has approximately the same magnitude of maximum force both in the working direction of the rollers and opposite.

The FIGS. 9a to 9d show representations like the FIGS. 8a to 8d with the difference that here there is a second phase position of the unbalanced shafts, in which the imbalance masses of the two unbalanced shafts 1, 2 in the illustrated situation have a twist angle φ of only 15 ° to each other. As if from a comparison of Fig. 9b With Fig. 8b can be seen, the courses of the excitation forces Ferr are shifted accordingly, so that a different total exciter force curve (not shown) results.

Like from the FIGS. 9c and 9d can be seen, results in this phase on sandy soil an oscillation response of the rollers 15, in which both in the working direction of the rollers and opposite result practically equal magnitude vibration amplitudes, while a Bodenreaktionskraftverlauf sets, in which the quotient of the maximum force of the course the floor reaction force in the working direction to the maximum force of the course of the floor reaction force in the direction opposite to the working direction is maximum. It So here is a ground reaction force optimized operation of the trench roller.

Fig. 10 shows a perspective top view of an unbalance exciter, which according to the construction principle Fig. 2 according to the concept Fig. 3 realized. As can be seen, here the main body 8 has two circular disks 20, which can be rotated about their center around a first axis of rotation r1. The bearings are not visible here. At a position on its circumference, the discs 20 each form a bearing point 21, on each of which one of the ends of an imbalance shaft consisting of a shaft 11 and an imbalance mass 3 is rotatably mounted about a second axis of rotation r2. At these bearing points opposite circumferential positions, the discs 20 counterweights 31, which reduce the imbalance generated by the imbalance masses 3 during rotation with the fundamental frequency about the first axis of rotation r1 and thereby deliberately reduce the Grunderregerkraft such that during normal operation, a certain ratio between the Basic excitation force and the additional excitation force is present.

At one of its ends, the shaft 11 has a pinion 6, which runs on the outer circumference of a stationary during operation, with the rotation axis r1 of the main body 8 and with the center of the discs 20 concentric gear 7. As can be seen, as the main body 8 is rotated about the first axis of rotation r1, the shaft 11 with the imbalance mass 3 attached thereto is rotated at a fixed distance about the axis of rotation r1. At the same time as a result of the running of the pinion 6 on the circumference of the gear 7, the shaft 11 is rotated about the second axis of rotation r2. As a result of the different circumferences of pinion 6 and gear 7, the shaft 11 rotates here with a speed f2, which corresponds to twice the drive speed f1. For adjusting the phase angle between the two rotations about the axes of rotation r1, r2 around the gear 7, for example by means of a rack (not shown) to be rotated about its center and thus about the first axis of rotation r1 around.

The Figures 11a and 11b schematically show the position of the imbalance mass of the unbalance exciter Fig. 8 in different angular positions with respect to the basic rotation at two different phase angles, wherein Fig. 11a shows a first phase position and Fig. 11b a second, compared to the first rotated by 45 ° phase angle. As can be seen, the imbalance weight 3 in each case performs a rotation of 180 ° about the second rotation axis r2 around a first rotation axis r1 at a basic rotation of the exciter of 90 ° about the second rotation axis r1 and a resulting total rotation of 270 °.
Fig. 12 shows a schematic plan view of the lower part of a two unbalance exciters 16 according to Fig. 10 equipped vibration plate. The upper part with the drive motor is not shown. The housing 27 of the exciter assembly is rigidly connected to the work plate 26 of the vibrating plate. The discs 20 of the unbalance exciter 16 are rotatably mounted about the first axis of rotation r1 and each unbalance exciter 16 via a central sleeve 22 torsionally rigidly interconnected. One of the two sleeves 22 is penetrated by an axle (not shown), which carries the gear 7 and connects it with an external gear 24. The unbalanced masses 3 of both unbalance exciters 16 are carried by a common shaft 11, which carries the pinion 6 at a central position, which runs on rotation of the unbalance exciter 16 on the circumference of the gear 7. On one side of the arrangement, the drive of the unbalance exciter 16 via a pulley 23 and on the other hand, the rotation of the gear 7 for the purpose of adjusting the phase position via a rack 25 which engages the gear 24.

Claims (17)

1. Method for operating a machine comprising an unbalance exciter with one or more rotatable unbalances (3) for generating a time-varying multiple-frequency excitation force which is generated by overlapping a time-varying base excitation force of a base frequency (f1) with one or more additional time-varying excitation forces of additional frequencies (f2) which are greater than the base frequency, wherein the phase between the base excitation force and at least one of the additional excitation forces is adjustable particularly continuously and further comprising a tool (15, 26) for acting on a working surface, which is coupled to the unbalance exciter for vibration stimulation, comprising the step

   a) operating the machine such that the tool (15, 26) stimulated to vibrate by the unbalance exciter (16) acts on a working surface in operation as intended, the method being characterized by the steps

   b) determining the vibration response of the tool to the vibration stimulation of the unbalance exciter (16) or of the course of the working surface reaction force in operation as intended;

   c) comparing the determined vibration response of the tool (15, 26) with a desired target vibration response or of the determined working surface reaction force course with a desired target working surface reaction force course; and

   d) adjusting the phase between the base excitation force and at least one of the additional excitation forces for varying the vibration excitation such that a vibration response of the tool (15, 26) results, which has an improved, particularly an as great as possible match with the target vibration response or that a working surface reaction force course results, which has an improved, particularly an as great as possible match with the target working surface reaction force course.
2. Method according to claim 1, characterized in that the phase is adjusted during operation.
3. Method according to one of the preceding claims, characterized in that the phase is adjusted in such a way that a vibration response of the tool (15, 26) or a working surface reaction force course results, for which the ratio between the maximum amplitude of the vibration response of the tool in tool working direction and the maximum amplitude of the vibration response of the tool in a direction opposite to the tool working direction or the ratio between the maximum force of the working surface reaction force course in working direction of the tool and the maximum force of the working surface reaction force course in a direction opposite to the working direction of the tool for given frequencies (f1, f2) and amplitudes of the base and additional excitation forces is maximal.
4. Method according to one of the preceding claims, characterized in that the phase, the frequency (f1, f2) and/or the amplitude of the base excitation force and/or of one or more of the additional excitation forces are adjusted particularly independently from one another in such a way that a vibration response of the tool (15, 26) or a course of the working surface reaction force results, in case of which the maximum amplitude of the vibration response of the tool or the maximum force of the working surface reaction force course doesn't exceed a certain maximum value in a direction opposite to the pressing direction of the tool (15, 26) on the working surface, in order to avoid a temporary contact loss between the tool (15, 26) and the working surface in operation as intended.
5. Method according to one of the preceding claims, characterized in that the resonance frequency of the system machine-tool-working surface is particularly determined continuously in operation as intended and the base frequency (f1) is set particularly continuously to a frequency which is a little above the determined resonance frequency, particularly to a frequency in the range between 105 % and 130 %, particularly between 110 % and 120 % of the determined resonance frequency.
6. Method according to one of the preceding claims, characterized in that the determination of the vibration response of the tool or the course of the working surface reaction force and potentially of the resonance frequency, the comparison with a desired target vibration response or with a desired target working surface reaction force course and the setting of the phase and potentially of the frequency (f1, f2) and/or the amplitude is carried out automatically by means of a machine control, particularly continuously during operation of the machine.
7. Machine for carrying out the method according to one of the preceding claims, comprising
   an unbalance exciter (16) with one or more rotatable unbalances (3) for generating a time-varying multiple-frequency excitation force which is generated by overlapping a time-varying base excitation force of a base frequency (f1) with one or more additional time-varying excitation forces of additional frequencies (f2) which are greater than the base frequency, wherein the phase between the base excitation force and at least one of the additional excitation forces is adjustable during operation particularly continuously, and
   a tool (15, 26) for acting on a working surface, which is coupled to the unbalance exciter for vibration stimulation, characterized in that
   the machine comprises means for determining the vibration response of the tool (15, 26) to the vibration stimulation of the unbalance exciter (16) in operation as intended of the machine and/or means for determining the course of the working surface reaction force in operation as intended of the machine,
   and the machine comprises a machine control, by means of which the phase between the base excitation force and at least one of the additional excitation forces is determined in operation automatically and particularly continuously in such a way that a vibration response of the tool (15, 26) or a course of the working surface reaction force results, for which the ratio between the maximum amplitude of the vibration response of the tool in tool working direction and the maximum amplitude of the vibration response of the tool in a direction opposite to the tool working direction or the ratio between the maximum force of the working surface reaction force course in working direction of the tool and the maximum force of the working surface reaction force course in a direction opposite to the working direction of the tool for given frequencies (f1, f2) and amplitudes of the base and additional excitation forces is maximal.
8. Machine according to claim 7, further comprising a machine control by means of which the phase, the frequency (f1, f2) and/or the amplitude of the base excitation force and/or of one or more of the additional excitation forces are adjusted automatically and particularly continuously during operation in such a way that a vibration response of the tool (15, 26) or a course of the working surface reaction force results, in case of which the maximum amplitude of the vibration response of the tool or the maximum force of the working surface reaction force course doesn't exceed a certain maximum value in a direction opposite to the pressing direction of the tool (15, 26) on the working surface, in order to avoid a temporary contact loss between the tool (15, 26) and the working surface in operation as intended.
9. Machine according to one of the claims 7 to 8, further comprising means for particularly continuously determining the resonance frequency of the system machine-tool-working surface in operation as intended.
10. Machine according to claim 9, further comprising a machine control by means of which the base frequency (f1) is set automatically during operation and particularly continuously to a frequency which is a little above the determined resonance frequency, particularly to a frequency in the range between 105 % and 130 %, particularly between 110 % and 120 % of the determined resonance frequency.
11. Machine according to one of the claims 7 to 10, characterized in that the machine is a drilling machine, a road milling machine, a tunnel milling machine, a ram or a machine for soil compaction, particularly a vibration plate or a vibration roller.
12. Machine according to one of the claims 7 to 11, characterized in that the unbalance exciter is formed in such a way that at least one of the additional excitation forces is varied over time with an additional frequency (f2) corresponding to an integral factor of the base frequency (f1), particularly with a frequency (f2) corresponding to the double base frequency.
13. Machine according to one of the claims 7 to 12, characterized in that the unbalance exciter is formed in such a way that separate unbalance masses (3) carrying out each a separate rotation movement are present for generating the base excitation force and the additional excitation forces.
14. Machine according to one of the claims 7 to 12, characterized in that the unbalance exciter is formed in such a way that a common unbalance mass (3) carrying out at least two overlapping rotation movements is present for generating the base excitation force and at least one additional excitation force.
15. Machine according to claim 14, characterized in that the unbalance exciter is formed in such a way that the exciter (16) has a counter weight (31) for decreasing the unbalance generated by the unbalance mass (3) during rotation with the base frequency (f1).
16. Machine according to one of the claims 7 to 15, characterized in that the unbalance exciter is formed in such a way that the base frequency (f1) and/or the additional frequencies (f2) are set particularly continuously and particularly during operation.
17. Machine according to one of the claims 7 to 16, characterized in that the unbalance exciter is formed in such a way that the amplitude of the base excitation force and/or the amplitude of the one or more of the additional excitation forces are set particularly continuously and particularly during operation, particularly independently from the respective frequency.

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