Vibration exciter for a soil-compaction device, method for adjusting a vibration amplitude of a vibration exciter for a soil-compaction device, and soil-compaction device having a vibration exciter

Abstract

The invention relates to a vibration exciter comprising: an exciter shaft rotatable about an axis of rotation; a first unbalanced mass which is arranged eccentrically with respect to the axis of rotation of the exciter shaft and which is mounted on the exciter shaft in such a way that it is rotatable, within a swinging area, relative to the exciter shaft about a swinging axis extending coaxially or in parallel with the axis of rotation of the exciter shaft, and that it can assume, depending on the direction of rotation of the exciter shaft, two different end positions in relation to the exciter shaft; and a second unbalanced mass which is mounted on the exciter shaft, can be caused by the exciter shaft to rotate about the axis of rotation, and is movable, independently of the direction of rotation of the exciter shaft, relative to the axis of rotation of the exciter shaft and relative to the first unbalanced mass between a first end position and a second end position. The invention also relates to a soil-compaction device having a vibration exciter of this kind, and to a method for adjusting a vibration amplitude of a vibration exciter.

Description

Vibration exciter for a soil compaction device, method for adjusting a vibration amplitude of a vibration exciter for a soil compaction device, and soil compaction device with a vibration exciter

[0001] The invention relates to a vibration exciter for a soil compaction device, a method for adjusting a vibration amplitude of a vibration exciter for a soil compaction device and a soil compaction device with a vibration exciter.

[0002] A vibration exciter for a soil compaction device and a soil compaction device equipped with it are known, for example, from US Pat. No. 7,059,802 B1. To improve the compaction effect of the soil compaction device shown, the compaction rollers are subjected to vibrations during compaction operation. The vibrations are generated by one or more vibration exciters. A vibration exciter comprises an exciter shaft that is driven in rotation about a rotational axis and on which at least one unbalanced mass is arranged eccentrically. An unbalanced mass in the present sense can also be referred to as an unbalanced weight or eccentric mass. Due to the imbalance caused by the eccentricity, vibrations useful for compaction are generated when the exciter shaft rotates.For this purpose, it is known to arrange at least one so-called reversing weight (hereinafter referred to as the first unbalanced mass) on the exciter shaft, which is eccentrically designed and mounted on the exciter shaft so that it can be adjusted between two end positions depending on the direction of rotation of the exciter shaft (i.e., the center of mass of the reversing weight lies outside the axis of rotation). Furthermore, a further unbalanced mass can be fixedly arranged on the exciter shaft (hereinafter referred to as the third unbalanced mass or exciter shaft weight), which always occupies the same relative position to the exciter shaft and is thus unchangeable in its relative position to the exciter shaft. This exciter shaft weight can therefore, for example, also be manufactured in one piece with the exciter shaft itself and be a single component consisting of a common body.The handling weight is rotationally decoupled from the exciter shaft and, if present, the exciter shaft weight arranged on it or is rotatable about a rotation axis and can assume different angular positions relative to the exciter shaft and, if present, the exciter shaft weight within a rotation range limited, for example, by stops. The rotation axis of the exciter shaft, optionally together with the exciter shaft weight, and the rotation axis of the handling weight relative to the exciter shaft weight can run coaxially to one another or offset parallel to one another, as described in EP2390416A2. The handling weight is repeatedly carried by the rotating exciter shaft by means of a stop (or the like) from a lower position to a kinematically dictated handling or rollover point, at which the handling weights are moved due to gravity (or inertia). The weight can tip over or turn over and strike a stop provided on the exciter shaft or the exciter shaft weight from the opposite side. Depending on the direction of rotation of the exciter shaft, the weight can thus assume a position in which the unbalanced mass of the weight is added to the exciter shaft weight during rotation, or the center of mass of the entire weight and the exciter shaft weight is further away in the radial direction from the axis of rotation of the exciter shaft, thus increasing the vibration amplitude.Alternatively, if the exciter shaft rotates in the opposite direction, it can assume a different position in which the mass of the envelope weight counteracts the mass of the exciter shaft weight during rotation of the exciter shaft, so that the center of mass of the entire envelope weight and the exciter shaft weight is closer in the radial direction to the axis of rotation of the exciter shaft, thus reducing the oscillation amplitude. With this arrangement, two different amplitudes can be generated at the same absolute speed, depending on the direction of rotation of the exciter shaft. A disadvantage of these vibration exciters is that the oscillation amplitude can only be adjusted between two modes, depending on the direction of rotation.

[0003] Furthermore, so-called continuously adjustable vibration exciters are known in the prior art, as described, for example, in DE 102010010037A1. Such vibration exciters enable continuous adjustment of the amplitude within an adjustment range of the relative positions of the envelope weight and the exciter shaft weight. A disadvantage of these vibration exciters is that a comparatively complicated and therefore cost-intensive adjustment mechanism is often required.

[0004] The vibration exciters relevant here are intended for use in soil compaction equipment, such as rollers, especially single-drum rollers and tandem rollers. Examples of such soil compaction equipment are described, for example, in DE102019002439A1, EP0945187A2, and DE102012017777A1.

[0005] Based on this, the object of the invention is to provide a structurally as uncomplicated and comparatively cost-effective way of providing the operator of a soil compaction device with a vibration exciter with more than two selection options with regard to available vibration amplitudes.

[0006] The problem is solved with a vibration exciter, a method, and a soil compaction device according to one of the independent claims. Preferred developments are specified in the dependent claims.

[0007] In a first aspect, the invention relates to a vibration exciter for a soil compaction device. The vibration exciter comprises an exciter shaft that is rotatable about a rotational axis, in particular a horizontal one. To drive the rotational movement of the exciter shaft, a A drive device comprising a drive motor, for example an internal combustion engine, electric motor, or hydraulic motor, is drive-connected to the exciter shaft of the drive motor directly or indirectly, in particular via a suitable drive gear. The drive device is designed such that the exciter shaft is driven to rotate in two different directions of rotation, specifically clockwise and counterclockwise. This can be achieved by reversing the drive direction of an output shaft of the drive motor directly or, for example, by a changeover gear arranged in the drive train between the drive motor and the exciter shaft.

[0008] The generic vibration exciter comprises at least one first unbalanced mass arranged eccentrically to the axis of rotation of the exciter shaft, which is mounted on the exciter shaft in such a way that it is rotatable within a reversal range relative to the exciter shaft about a reversal axis running coaxially or parallel to the axis of rotation of the exciter shaft and can assume two different end positions depending on the direction of rotation of the exciter shaft relative to the exciter shaft. For this purpose, the first unbalanced mass can be mounted on the exciter shaft and / or on an optional third unbalanced mass, described in more detail below, for example via a pivot bearing, in particular a plain bearing, consisting of a bearing bush enclosed by the first unbalanced mass and a bearing axis guided through the bearing bush, for example the exciter shaft, whose axis of rotation runs parallel or coaxially to the axis of rotation of the exciter shaft.The first unbalanced mass, designed as a turnover weight, has its own center of mass (first center of mass). Due to the adjustability of the first unbalanced mass relative to, for example, the third unbalanced mass and / or by using a turnover axis that runs parallel but not coaxial with the axis of rotation of the exciter shaft, the radial distance of the center of mass of the first unbalanced mass from the axis of rotation and thus the eccentricity between two values ​​can be varied by changing the direction of rotation of the exciter shaft. In order to be able to determine the extent of the rotational or turnover movement of the first unbalanced mass relative to the exciter shaft within the intended rotation range, which is usually less than 190°, one or more stops can be provided via which the third unbalanced mass and / or the exciter shaft and the first unbalanced mass strike one another in the direction of the current direction of rotation.If the third unbalanced mass and / or the exciter shaft and the first unbalanced mass are in contact with each other in the direction of the current rotation, the third unbalanced mass and / or the exciter shaft will entrain the first unbalanced mass as the rotation continues. The rotational movement of the first unbalanced mass can thus preferably be driven exclusively and directly by the entrainment of the third unbalanced mass and / or the exciter shaft.

[0009] By definition, the center of mass (also known as the center of gravity, center of weight or center of gravity) of the respective unbalanced mass refers in particular to the mass-weighted mean of the positions of the mass points of the body forming the respective unbalanced mass.

[0010] Essential to the invention is that the vibration exciter according to the invention has a second unbalanced mass in addition to the first unbalanced mass. The second unbalanced mass is also mounted on the exciter shaft and, during vibration excitation operation, is set in rotation about the axis of rotation or is carried along in its rotational movement. The second unbalanced mass also has its own center of mass (second center of mass). The overall center of mass and thus the resulting outward eccentricity of the unbalanced arrangement driven by the exciter shaft is thus determined at least essentially by the totality of at least the first and second unbalanced masses as well as the relative position of the first and second centers of mass relative to the axis of rotation.The second unbalanced mass is also adjustable between a first and a second end position relative to the exciter shaft, whereby the two end positions of the second unbalanced mass differ from one another in that the unbalance or eccentricity resulting from the second unbalanced mass with respect to the axis of rotation must be different from one another, which is not necessary for the two end positions of the first unbalanced mass. In compression or vibration excitation operation, when the exciter shaft rotates about its axis of rotation at a defined speed, for example, the second unbalanced mass can only assume and maintain one of the two end positions at a time. The second unbalanced mass can be brought into the first or second end position independently of the first unbalanced mass and also independently of the direction of rotation of the exciter shaft.The adjustment relative to the axis of rotation of the exciter shaft and relative to any third imbalance mass, which is independent of the direction of rotation of the exciter shaft, takes place in particular along a guide, particularly along a linear guide running radially or skew to the axis of rotation. The guide is ideally designed in such a way that not only the first and second end positions of the second imbalance mass relative to the exciter shaft are clearly defined, but also, in particular, the adjustment path from the first end position to the second end position, particularly relative to the exciter shaft.By means of the second unbalanced mass, which is adjustable relative to the first unbalanced mass and relative to the exciter shaft between a first and a second end position independently of the direction of rotation of the exciter shaft, a further adjustable unbalanced mass is added to the vibration exciter in addition to the adjustable first unbalanced mass, whereby the mechanisms that trigger and drive the adjustment of the first and second unbalanced masses relative to the exciter shaft are different from one another. Overall, this arrangement thus allows at least three different relative positions of the centers of mass of the first and second unbalanced masses to be represented by two variable, defined end positions of the first and second unbalanced masses relative to the exciter shaft, whereby the drive mechanisms of the first and second unbalanced masses underlying the adjustment are different from one another.The operator thus has access to at least three vibration amplitudes that can be generated by the vibration exciter. It should be noted that these refer to the same rotational speed of the exciter shaft or the same vibration frequency. A change in the vibration amplitude due to a change in the exciter shaft. the speed of the excitation shaft or the frequency is also possible and is included in the invention.

[0011] The spectrum of amplitudes that can be generated with the vibration exciter according to the invention can be further varied if, in addition to the first and second unbalanced masses, a third unbalanced mass in the form of an exciter shaft weight is present. The third unbalanced mass is also arranged eccentrically to the axis of rotation of the exciter shaft and, unlike the first and second unbalanced masses, is fixedly connected to it. The exciter shaft and the third unbalanced mass thus ideally form a unit that is non-adjustable relative to one another. Eccentric refers to the center of mass (third center of mass) of the third unbalanced mass. The body to be assumed for the third unbalanced mass is thus formed by the region(s) of the third unbalanced mass that are eccentric to the axis of rotation, but in particular also by the entirety of the exciter shaft and the first unbalanced mass.The third unbalance mass and exciter shaft can be a rigid, even single-piece, and materially uniform assembly. The relative position of the unbalance mass to the exciter shaft is thus clearly defined and unchangeable during normal operation. By combining the first and second unbalance masses and their possible adjustment between two defined end positions relative to the exciter shaft and thus also relative to the third unbalance mass, a total of four relative positions of the three unbalance masses to one another can be achieved, thus generating a total of four vibration amplitudes during vibration excitation operation or when the exciter shaft rotates around its axis of rotation.

[0012] The specific design of the guide for the second imbalance mass between its two end positions can vary. However, it is preferred if the second imbalance mass is mounted on the exciter shaft and / or the third imbalance mass via a linear guide, wherein the linear guide is designed such that the second imbalance mass is adjusted between the first and second end positions along a linearly extending adjustment axis. A linear guide is comparatively easy to manufacture and, in practical use, leads to more reliable movement sequences.

[0013] The linear guide is preferably designed such that it defines or has an adjustment axis that runs radially to the rotation axis, wherein the adjustment axis is a movement axis and is formed, for example, by one or more sliding guides, rails, grooves, bores, one or more elongated holes or the like and a counter element sliding along them, such as an axle, a sliding block, a bushing, counter rail, etc. The movement axis preferably runs such that it intersects the rotation axis of the exciter shaft perpendicularly. The movement axis additionally or alternatively preferably intersects both the second center of mass (i.e. the center of mass of the second unbalanced mass) and / or the rotation axis of the exciter shaft.

[0014] The linear guide may further comprise, additionally or alternatively, at least one through-hole in the exciter shaft extending linearly with respect to its longitudinal axis, and a guide axis fixedly connected to the second unbalanced mass, which extends through the linear through-hole. This solution is extremely compact, since a cavity extending through the exciter shaft is used to guide the second unbalanced mass.

[0015] However, the weakening of the structural integrity of the exciter shaft associated with the through-hole can be disadvantageous, particularly in compact yet very powerful vibration exciters. Another complementary or alternative design option for the linear guide could be to include two opposing, parallel guide flanks that are fixedly connected to the second imbalance mass and guided along an outer surface of the exciter shaft. The guide flanks can be formed, for example, by the opposing longitudinal flanks of an elongated hole. In this variant, the second imbalance mass is thus guided on the outside of the exciter shaft.In addition to the rotational locking of the second imbalance mass on the exciter shaft, as described in more detail below, it can be provided that the exciter shaft, in the contact area with the guide flanks, is elongated, in particular oblong, in contrast to its usual circular cross-section perpendicular to the rotation axis. Thus, on its outer surface, it has at least two mutually parallel, flat sliding surfaces that are in flat contact with the corresponding counter-surface of the guide flanks. The areas of the elongated hole connecting the guide flanks can serve as an adjustment stop or adjustment travel limit.

[0016] In order to prevent the relative position of the second imbalance mass relative to the exciter shaft and / or third imbalance mass from changing when the direction of rotation of the exciter shaft changes, it is advantageous if the vibration exciter has a rotation lock designed such that the second imbalance mass is at least substantially rotationally fixed relative to the axis of rotation of the exciter shaft. In this case, rotationally fixed does not mean that the second imbalance mass is also stationary. A rotationally fixed arrangement of the first imbalance mass and / or exciter shaft relative to the second imbalance mass exists when no at least significant movement of the second imbalance mass relative to the third imbalance mass and / or the exciter shaft about the axis of rotation is possible.In a plane perpendicular to the axis of rotation, the second unbalanced mass can therefore be adjusted relative to the third unbalanced mass and / or exciter shaft, for example along a steep curve or similar extending in a longitudinal direction, but preferably exclusively linearly in a longitudinal direction. However, the rotation lock is preferably designed such that rotation of the second unbalanced mass relative to the third unbalanced mass and / or exciter shaft about the axis of rotation of the exciter shaft is not possible, at least not to enable movement of the second unbalanced mass from its first to its second end position. The rotation lock is designed such that the second unbalanced mass follows a rotational movement of the exciter shaft about the axis of rotation in both possible directions of rotation or, via the rotation lock, is dependent thereon directly or. indirectly, even when the direction of rotation changes. The anti-rotation device in this context essentially serves to ensure that the second unbalanced mass is carried along in its respective end position in both directions of rotation of the exciter shaft and does not leave its respective end position due to a change in the direction of rotation of the exciter shaft or dependent on this and move to the other end position.However, this anti-rotation device does not rule out the possibility that the bearing of the second unbalanced mass on the exciter shaft and / or the third unbalanced mass has play or even a comparatively small degree of freedom of movement in and against the direction of rotation of the exciter shaft. This can be particularly desirable and helpful if the second unbalanced mass is to be adjusted between its end positions solely depending on the force of gravity acting on it, as described in more detail below, and / or is spring-loaded in and / or against the direction of rotation relative to the exciter shaft and / or the third unbalanced mass, for example to counteract torsional vibrations occurring within the vibration exciter.The anti-rotation device is thus preferably designed in such a way that it limits any possible adjustment of the second imbalance mass relative to the exciter shaft and / or the third imbalance mass about the rotational axis of the exciter shaft to very few degrees, in particular to a range of less than 5 degrees. The range of movement of the second imbalance mass about the rotational axis is thus considerably smaller, for example by at least a factor of 15 or more, than the range of movement of the first imbalance mass.

[0017] The first and / or second end positions of the second imbalance mass relative to the exciter shaft and / or the third imbalance mass can be determined by a mechanical stop, in particular a stop formed by the exciter shaft itself and / or the third imbalance mass. The stop can be damped, but is preferably undamped. The same applies to the two end positions of the first imbalance mass.

[0018] Preferably, the second unbalanced mass has a center of mass (second center of mass) whose distance in the radial direction from the axis of rotation of the excitation shaft is greater in the first end position than in the second end position. This makes it possible to generate two different eccentricities relative to the axis of rotation with the two mutually different end positions.

[0019] It is ideal if the center of mass of the second unbalanced mass, when adjusting the second unbalanced mass from the first end position to the second end position, passes through a virtual reference plane in which the axis of rotation of the exciter shaft lies and which runs perpendicular to the adjustment direction (in particular to an adjustment direction running along a linear axis) of the second unbalanced mass between the first and the second end position. This ensures that, regardless of any rotational movement and / or direction of rotation of the exciter shaft, no centrifugal forces act on the second unbalanced mass that could displace it from its respective end position, since the center of mass is spaced from the axis of rotation in each of the two end positions and, moreover, is clearly positioned with respect to this plane for each end position exclusively on one of the two sides. the plane (for example in front of the plane) and the other end position is positioned exclusively on the other of the two sides of the plane (for example behind the plane). In both cases, the centrifugal forces acting on the second unbalanced mass during rotation have a stabilizing effect in the respective end position (ideally in conjunction with the anti-rotation device and / or the longitudinal guide). This further development is characterized in that the second unbalanced mass is centrifugally stabilized or centrifugally locked in both end positions during rotation of the exciter shaft. In addition or alternatively, one or more locking devices can also be provided which fix the second unbalanced mass in one or both of the end positions relative to the exciter shaft and / or third unbalanced mass. These can be, for example, mechanical and / or magnetic and / or electromagnetic locking devices.It may also be provided, additionally or alternatively, that the adjustment of the second imbalance mass relative to the third imbalance mass and / or relative to the excitation shaft is carried out by means of a motor drive, for example a spindle drive or similar. However, a purely gravity-driven adjustment without an additional locking device of the type described above is preferred.

[0020] Each of the first, second and third unbalance masses has its own center of mass. Based on this, it can be advantageous if the first, the second and, if present, the third unbalance mass are adjustable relative to one another in such a way that when the second unbalance mass is in at least one of the two end positions and the first unbalance mass is in at least one of the two mutually different end positions, the centers of mass of the first, the second and, if present, the third unbalance mass, in particular when projected into a virtual reference plane to which the axis of rotation is perpendicular, lie on a common straight line running in the radial direction to the axis of rotation.Ideally, the arrangement of the two or three centers of mass on a common straight line, especially when projected onto a virtual reference plane to which the rotation axis is perpendicular, is present in three or even four possible configurations. In this way, the vibration exciter can generate the maximum and minimum possible total eccentricity for the individual unbalance masses of the first, second, and possibly third unbalance masses, or, at a defined rotational speed, the maximum and minimum vibration amplitudes, and one or two vibration amplitudes lying between these two vibration amplitudes.

[0021] It is advantageous if the second unbalanced mass is mounted on the exciter shaft in such a way that adjustment of the second unbalanced mass from the first to the second end position relative to the exciter shaft and / or third unbalanced mass is carried out, in particular exclusively, by gravity. This can be achieved in particular by setting a specific rotational position of the exciter shaft in which, for example, a rectilinear axis of movement of the second unbalanced mass relative to the exciter shaft and / or third unbalanced mass runs in the vertical direction (or at least almost in the vertical direction). The second unbalanced mass can then, for example, fall from one of the two end positions in the vertical direction downwards into the other of the two end positions due to its own weight. If the other end position is to be assumed by the second imbalance mass, the exciter shaft must be rotated such that the current end position of the second imbalance mass, viewed in the vertical direction, is above the end position to be assumed, in particular perpendicular to it. A separate drive for adjusting the second imbalance mass is then not required, since the drive required for the described rotational movement of the exciter shaft is already present. However, it is preferred if the exciter shaft drive enables two different drive modes, specifically a vibration excitation mode with a comparatively high speed and an "adjustment mode" for the second imbalance mass with a comparatively low speed or with the option of being able to rotate the exciter shaft, for example, specifically in one and / or the other direction of rotation by just a few degrees.

[0022] Particularly for the gravity-driven adjustment of the second imbalance mass from one end position to the other, it is advantageous if the vibration exciter comprises a device for detecting at least one, in particular two mutually different, set rotational positions of the exciter shaft. The or these two set rotational positions can, for example, be configured such that a movement axis of the second imbalance mass runs vertically perpendicular to the horizontal plane between the two end positions. The detection of a specific rotational position of the exciter shaft relative to a bearing structure for the rotational support of the exciter shaft can be determined, for example, by means of a rotation angle sensor, in particular a contactless one.Additionally or alternatively, it is also possible to record the actual adjustment movement of the second imbalance mass, for example, using a contact sensor or similar, and thereby detect when the exciter shaft reaches the rotational position required to adjust the second imbalance mass. Furthermore, with a comparatively slow adjustment of the exciter shaft, the slippage of the second imbalance mass can also be detected indirectly, for example acoustically (caused, for example, by the impact noise of the second imbalance mass upon reaching the desired end position) by a pressure fluctuation generated in a hydraulic motor and / or by a voltage fluctuation generated in an electric motor.

[0023] Furthermore, or alternatively, it is also possible to provide an additional drive which is solely for adjusting the exciter shaft to at least one, in particular specific, rotational position in which the second imbalance mass changes from the current end position to the other end position. The vibration exciter can thus comprise a device, for example a special control system, for selectively adjusting and maintaining at least the first and second adjustment rotational positions of the exciter shaft, wherein in the first adjustment rotational position, the second imbalance mass is adjusted to the first end position, and in the second adjustment rotational position, the second imbalance mass is adjusted to the second end position relative to the third imbalance mass.

[0024] For the practical use of the vibration exciter according to the invention, it is advantageous if it comprises a control unit or is controlled by one which is designed in such a way that that when an operating mode is selected manually by an operator or automatically as part of a compression control system, from at least three, in particular four, different possible operating modes dependent on or predetermined by a total eccentricity of the vibration exciter, it controls the assumption of the respective required relative positions of the first, the second and the second unbalanced mass to one another. The eccentricity refers to the distance of the center of mass of the respective unbalanced mass radially to the axis of rotation. The total eccentricity, on the other hand, refers to the distance of the center of mass of these three unbalanced masses together. Ultimately, therefore, the following applies: at a constant speed of the exciter shaft, the generated vibration amplitude increases with increasing eccentricity and vice versa.The control unit is preferably designed such that it specifies at least one set rotational position of the exciter shaft and / or a direction of rotation of the exciter shaft. By controlled adjustment of the set rotational position of the exciter shaft, the adjustment of the second imbalance mass can be carried out in a targeted manner, particularly when it is gravity-driven. By specifying a direction of rotation, however, the relative position of the first imbalance mass relative to the exciter shaft and / or third imbalance mass during rotational operation is defined between its two end positions. Additionally or alternatively, the control unit can time-control the assumption of a specified set rotational position of the exciter shaft and then the acceleration of the exciter shaft in a specified direction of rotation.This is advantageous in that, for the adjustment of the second imbalance mass, it is initially advantageous and important that the exciter shaft rotates only comparatively slowly and / or even remains in the set rotational position for a specific time window, so that the adjustment of the second imbalance mass from one end position to the other end position can actually occur. However, it is subsequently advantageous if the exciter shaft is accelerated rapidly, ideally abruptly, so that the centrifugal forces acting on the second imbalance mass exceed the gravitational force acting on the second imbalance mass, ideally within half a rotation, particularly preferably within a quarter of a rotation of the exciter shaft, in order to prevent the second imbalance mass from "falling back."The rotational speed of the excitation shaft in vibration excitation mode is therefore considerably higher than the maximum possible rotational speed for adjusting the second unbalance mass.

[0025] The vibration exciter preferably has a sensor device designed to detect at least one of the two different end positions by the first unbalanced mass and / or the first and / or second end position of the second unbalanced mass. This can be done by directly and / or indirectly detecting the respective end position. For example, contact sensors or contactless sensors, optical, mechanical or acoustic sensors, etc. can be used for this purpose. The sensor data determined by the sensor device can in particular be fed to the control unit and / or the adoption of certain end positions determined by the sensor device can also be displayed on a display device.

[0026] A further aspect of the invention lies in a method for adjusting the vibration amplitude of a vibration exciter for a soil compaction device, in particular for a vibration exciter according to the invention. For details of generic and inventive vibration exciters, the above information also applies to the method according to the invention. In a first step, an exciter shaft and, if present, a third unbalanced mass connected to the exciter shaft are rotated into one of two defined, preferably offset by 180°, set rotational positions about a rotational axis of the exciter shaft. It is then provided that a second unbalanced mass is adjusted, in particular driven by gravity, into one of two defined end positions depending on the set rotational position to which the exciter shaft has been adjusted.This determines the relative position of the second imbalance mass relative to the exciter shaft and / or the third imbalance mass. A rotational direction of the exciter shaft is then specified, and the exciter shaft is accelerated into a rotational movement around a rotational axis of the exciter shaft in the direction of the specified rotational direction. This results in a defined relative position of a first imbalance mass being set from two defined possible relative positions of the first imbalance mass relative to the third imbalance mass and / or the exciter shaft, depending on the current rotational direction of the exciter shaft.Thus, in both cases, a rotation of the exciter shaft is used to adjust the first and second unbalanced masses, whereby in one case the decisive factor is reaching and at least briefly maintaining (or slowly overcoming) a certain rotational position of the exciter shaft regardless of the direction of rotation of the exciter shaft, and in the other case the ideally comparatively rapid initiation of the rotational movement in a certain direction of rotation of the exciter shaft.

[0027] In the first step, the current rotational position of the excitation shaft can also be detected. Depending on the currently detected rotational position of the excitation shaft, the excitation shaft can be rotated further around the rotational axis until the currently detected rotational position matches the one defined rotational position. This can be automated and controlled by a control unit.

[0028] The one of two defined end positions of a second imbalance mass relative to the third imbalance mass and one of two defined relative positions of the first imbalance mass relative to at least the exciter shaft and, if present, the third imbalance mass, specified by the method according to the invention, can be achieved by selecting a desired total eccentricity (or vibration amplitude) from one of a total of at least three, in particular exactly four, available and mutually different total eccentricities (or vibration amplitudes at a defined rotational speed of the exciter shaft) of the vibration exciter. This can be done manually or automatically.

[0029] The end positions in steps b) and / or d) are preferably reached by mechanically stopping the respective first unbalanced mass and / or second unbalanced mass against an adjustment stop, wherein an adjustment stop can be provided for each of the end positions.

[0030] Finally, one aspect of the invention also relates to a soil compaction device with a vibration exciter according to the invention. Such a soil compaction device can be, for example, a soil roller, in particular a tandem roller or a single-drum roller. In rollers, the vibration exciter is preferably arranged within a drum-shaped roller bandage that rolls on the soil to be compacted.

[0031] The soil compaction device according to the invention can comprise a control unit which is designed to carry out a method according to the invention

[0032] It is also possible for the soil compaction device to have two or more vibration exciters according to the invention.

[0033] Additionally or alternatively, the individual unbalance masses of the vibration exciter can also be arranged as subunits distributed along the exciter shaft, particularly with respect to a mirror plane running perpendicular to the axial direction of the rotation axis, in order to achieve, for example, equal bearing forces and symmetrical amplitudes in the direction of the rotation axis. It is essential that these subunits of an unbalance mass are each, as a whole, either stationary relative to the exciter shaft or, during an adjustment process, are moved together from one end position to the other by the same effective impulse.

[0034] The invention is explained in more detail below with reference to the exemplary embodiments shown in the figures. They show schematically: Figure 1 is a side view of a tandem roller type soil compaction device; Figure 2 is a side view of a soil compaction machine of the roller type; Figure 3 shows a view of a vibration exciter with drive train; Figure 4A is a plan view of a component forming a third unbalance mass; Figure 4B is a plan view of a component forming a first unbalance mass; Figure 4C is a plan view of a component forming a second unbalance mass; Figures 5A and 5B show two end positions of the first unbalanced mass relative to the third unbalanced mass; Figure 6 shows the arrangement from Fig. 5A with a third unbalance mass inserted; Figures 7 A and 7B illustrate the effect of the adjustability of the second unbalance mass relative to the third unbalance mass; Figures 8A to 8D Overview of four different relative positions of the first, second and second unbalance masses with decreasing total eccentricity in the starting position; Fig. 9A to 9D representations of the amplitudes assigned to the relative positions from Figs. 9A to 9D at a given speed; Fig. 10 is a perspective oblique view of an alternative embodiment of a vibration exciter; and Fig. 11 is a flowchart of a method.

[0035] Identical or functionally identical components are identified by the same reference symbols in the figures. Recurring components are not numbered separately in each figure.

[0036] Figures 1 to 2 show various soil compaction devices 1 with one or more vibration exciters 2 (each indicated by a dashed line) in side view. Each of the soil compaction devices comprises a ground contact device 3, via which it is in direct contact with the subsoil U to be compacted and transmits vibrations generated by the vibration exciter(s) 2 into the subsoil. One or more vibration exciters 2 can be assigned to a soil sound timing device 3. For extensive soil compaction, the soil compaction devices 1 are moved across the subsoil in a forward and / or backward direction a, either by their own propulsion or at least partially by muscle power.

[0037] Fig. 1 shows a self-propelled soil compaction machine 1 of the tandem roller type, in which the soil vibration synchronization devices 3 are designed as front and rear roller drums, in the interior of which at least one vibration exciter 2 is arranged. The soil compaction machine comprises a machine frame 4 on which a driver's cab 5 is arranged. The drive energy required for driving and working is generated by a drive motor 6. The soil compaction machine 2 can be connected to the front and rear roller drums via a pivot steering system. An articulated design of this type of soil compaction machine is also possible. Such soil compaction machines can be used, for example, in road construction for compacting an asphalt surface.

[0038] The soil compaction device 1 shown in Fig. 2 is a roller train, the ground contact device 3 of which is a front roller drum, in the interior of which at least one vibration exciter 2 The roller can have an articulated machine frame 4, the front and rear frame halves of which can be connected to each other via an articulated pendulum joint. Drive wheels can be provided on the rear carriage. These soil compaction devices can also be self-propelled.

[0039] Such soil compaction devices 1 can be hand-operated and / or remotely controlled by an operator traveling with the soil compaction device 1.

[0040] Fig. 3 shows, by way of example, further details of a possible design of a vibration exciter 2 and its connection to a drive train. The drive motor 6, for example an electric or hydraulic motor, is in driving connection with the vibration exciter 2 via a drive train 8, here for example a belt drive, although a direct drive is also possible. The drive train 8 is connected on the output side to an exciter shaft 9, which is mounted within a housing 10 so as to be rotatable about a rotation axis R. The drive train 8 and / or the drive motor 6 are designed such that the exciter shaft 9 can be rotated optionally clockwise or counterclockwise.This can be done directly by switching the drive direction of the drive motor 6 or via a changeover gear located in the drive train. An optional third unbalanced mass U3, a first unbalanced mass U1 and a second unbalanced mass U2 are mounted on the exciter shaft 9 in such a way that the three unbalanced masses U1, U2 and U3 are carried along by the rotating exciter shaft 9 and set in rotation. During oscillation operation of the vibration exciter 2, all three unbalanced masses U1, U2 and U3 rotate together with the exciter shaft 9 around the rotation axis R. It is understood that the respective unbalanced masses U1, U2 and U3 can be formed by one component but also by several components. The unbalanced masses U1, U2 and U3 thus each designate an interacting unit with the functionalities described in more detail below. The unbalanced mass U3 can be formed in one piece and even in one piece with the excitation shaft 9.The unbalanced mass U1 is a so-called turnover weight, the relative position of which to the unbalanced mass U3 is adjustable between two end positions depending on the direction of rotation of the exciter shaft 9 about the rotation axis R. The unbalanced mass U2, on the other hand, is independent of the direction of rotation of the exciter shaft 9 between a first (shown in Fig. 4 as a solid line) and a second (shown in Fig. 4 as U2' with a dashed line) end position, which differ from one another in their eccentricity, i.e., in the distance of their respective center of mass from the rotation axis R, as described in more detail below.

[0041] The soil compaction device can have a control unit 11, which is designed to set and / or control the adjustment options explained below for providing various vibration amplitudes. A sensor device 12 can also be provided, which detects one or more parameters relevant for setting and / or controlling these adjustment options. For this purpose, the sensor device 12 can, for example, have a rotation angle sensor 13, a rotation direction sensor 14, a rotation speed sensor 15, a position sensor 16 for detecting determining the relative position of the first unbalanced mass U1 and / or the second unbalanced mass U2 relative to the third unbalanced mass U3 and / or to the exciter shaft 9. The control unit 11 can be signal-connected to the sensor device 12. Furthermore, a display device 17, for example a monitor, and / or a selection device 18, for example an input keyboard, can be provided and signal-connected to the control unit 11, via which a current operating mode can be displayed and / or selected.

[0042] Figures 4A, 4B and 4C each show, in a top view, an exemplary structural design of the third unbalanced mass U3 with excitation shaft 9 (Fig. 5A), the first unbalanced mass U1 (Fig. 5B) and the second unbalanced mass U2 (Fig. 5C).

[0043] According to Fig. 5A, the third unbalanced mass U3 can have a mass unit essentially in the form of a half-shell 19, which extends semicircularly and at a radial distance therefrom around the axis of rotation R. Furthermore, a receiving pot 20 can be provided, as well as a rotation stop 21, which represents a rotation limit with respect to the first unbalanced mass U1, as explained in more detail below. The unbalanced mass U3 has a center of mass M3, which is spaced a distance EX3 in the radial direction from the axis of rotation R. This distance EX3 designates the eccentricity of the unbalanced mass U3. The exciter shaft 9 can be formed integrally with the unbalanced mass U3. In a partial area, this has part of a radial guide, for which purpose the exciter shaft 9 has two opposing contact surfaces 26 which run linearly and parallel to one another and for this purpose has, for example, an oblong outer contour.The two contact surfaces 26 are each connected to each other via a rounded bridging area. In this area, in which, as shown below, the second unbalanced mass U2 is guided, the excitation shaft 9 is thus non-circular in cross-section perpendicular to the rotation axis 09.

[0044] Fig. 58 shows the first unbalanced mass U1 in a top view. This can, for example, be designed in the shape of a circular segment and, as part of a rotary bearing, include an exciter shaft through-hole 22. The center of mass of the first unbalanced mass U1 is designated M1. The first unbalanced mass U1 can further include two opposing stop flanks 23, 23', which can be designed to engage the rotation stop 21 of the third unbalanced mass U3.

[0045] The second unbalanced mass according to Fig. 4C has a center of mass M2. A linear guide 27 is provided in this case by the opposing and parallel longitudinal flanks 25 of an elongated hole 24, which has, for example, an oblong contour in the plane of the illustration. The center of mass M2 is located in the elongated hole 24.

[0046] The present illustrations show the centers of mass M1, M2 and M3 in a projection into the viewing plane of the figures or in a virtual reference plane perpendicular to the rotation axis.

[0047] Figures 5A and 5B first illustrate the dependence of the relative position of the third unbalanced mass U3 relative to the first unbalanced mass U1 on the direction of rotation of the exciter shaft. The current direction of rotation of the exciter shaft 9 is indicated by R1 and R2. The first unbalanced mass U1 is arranged on the exciter shaft 9, for which purpose the exciter shaft 9 is guided through the exciter shaft through-opening 22. Upon rotation of the exciter shaft 9 counterclockwise in the direction RI, the first unbalanced mass U1 strikes the rotation stop 21 with its side flank 23, and upon rotation of the exciter shaft 9 clockwise in the direction R2, it strikes the side flank 23'. The unbalanced mass U1 thus strikes on different sides depending on the direction of rotation R1 / R2 and is then carried along by the excitation shaft 9 as the rotation continues in the respective direction of rotation.The adjustment movement of the first unbalanced mass U1 relative to the third unbalanced mass U3 and the exciter shaft (9) is opposite to the respective direction of rotation of the exciter shaft 9 and runs around the reversal axis UA, which in the present embodiment runs coaxially to the axis of rotation R. Due to the two mutually different relative positions of the center of mass of the third unbalanced mass U3 and the first unbalanced mass U1 that can be achieved in this way, the center of mass of the entirety of the two unbalanced masses U3 and U1 can thus be changed in its radial distance from the axis of rotation R, whereby two different vibration amplitudes can be generated at a defined rotational speed depending on the direction of rotation.

[0048] In Fig. 6, in addition to the arrangement in Figures 5A and 5B, the second unbalanced mass U2 is added. This is also positioned on the exciter shaft 9, but is secured against rotation. The exciter shaft 9, which has a non-circular cross-section perpendicular to the rotation axis R in the passage area through the elongated hole 24, rests with its opposing contact surfaces 25 in a form-fitting manner on the longitudinal flanks 25 of the second unbalanced mass U2 and thus forms the linear guide 27, which enables adjustment of the second unbalanced mass U2 in the radial direction. As a result, the second unbalanced mass U2, in contrast to the first unbalanced mass U1, follows every rotational movement of the exciter shaft 9 in both directions of rotation, in a rotation-secured manner, particularly when the current direction of rotation of the exciter shaft 9 is reversed. The longitudinal guide 27 thus simultaneously forms a rotation lock 35 of the second unbalanced mass U2 with respect to the third unbalanced mass U3 and the exciter shaft 9.At the same time, however, an adjustment of the second unbalanced mass U2 along the linear guide 27 formed by the elongated hole 24 is possible, in this case in the radial direction to the axis of rotation R. This can be done by a special drive element for the adjustment or also dependent on gravity. For this purpose, the exciter shaft 9 is brought into a rotational position and, if necessary, held in this rotational position in which the axis of movement of the second unbalanced mass U2 preferably runs in the vertical direction. The extent of this adjustment is limited in the radial direction by the stops formed between the elongated hole 24 and the exciter shaft 9. As with the first unbalanced mass U1, an adjustment of the relative position of the second unbalanced mass U2 with respect to the third un- balancing mass U3 and the excitation shaft 9 is possible, but in a different direction, namely in particular in the radial direction to the rotation axis R (indicated in Fig. 6 with the arrow C.

[0049] Figures 7A and 7B show positions in which the second unbalanced mass U2, driven by gravity, automatically slides into one of its two end positions. Fig. 7A shows the first end position and Fig. 7B the second end position. The second unbalanced mass U2 slides along the linear guide between the exciter shaft 9 and the elongated hole 24 under its own weight into a stop position. The second unbalanced mass U2 can in particular be designed such that the second center of mass M2 not only changes its distance in the radial direction from the axis of rotation R between the two end positions, but also passes through a virtual plane in which the axis of rotation R runs and which is oriented transversely, in particular perpendicular to the adjustment direction of the second unbalanced mass M2 relative to the exciter shaft 9. This virtual plane is designated H in Figures 7A and 7B.This means that not only the radial distance of the center of mass M2 of the second unbalanced mass U2 from the axis of rotation R differs in the two end positions, but also the side of the position of the second center of mass M2 relative to the exciter shaft 9, which then lies on opposite sides of this plane. This is advantageous in that in both end positions, during rotation of the exciter shaft 9, centrifugal forces acting on the second unbalanced mass U2 act in the direction of the respective stop between the exciter shaft 9 and the second unbalanced mass U2 and stabilize it in its current relative position, so that additional locking means which fix the second unbalanced mass in one or both of its end positions and which are fundamentally possible and encompassed by the invention can be dispensed with.

[0050] Figures 7A and 7B further illustrate that simply by assuming the two end positions of the second unbalanced mass U2, the radial distance of the total center of mass MS is changed. Figures 7A and 7B show the positions of the centers of mass M1, M2, and M3 of the three unbalanced masses U1, U2, and U3. The total center of mass MS of these three unbalanced masses results from the relative position of these three elements relative to the rotation axis R. In the arrangement of the three unbalanced masses U1, U2 and U3 in Fig. 7B, the unbalance effect of the second unbalanced mass O2 is added to the unbalance effect of the first and third unbalanced masses U1 and U3, whereas the unbalance effect of the second unbalanced mass U2 in the arrangement according to Fig. 7A is deducted from the unbalance effect of the unbalanced masses U1 and U3, since its center of mass M1 is located on the opposite side of the other two centers of mass M2 and M3 relative to plane H.Accordingly, the total eccentricity EXS or the vibration amplitude generated at a defined rotational speed of the excitation shaft 9 can be changed solely by adjusting the relative position of the second unbalance mass U2 with respect to the first and the first unbalance masses U1 and U3 and is specifically smaller in Fig. 7A than in Fig. 7B.

[0051] Figures 7A and 7B also show the possibility of designing the construction of the unbalanced masses U1 to U3 and their guides for changing their relative positions to each other in such a way that their centers of mass M1, M2 and M3 lie on a common straight line G in the respective end positions.

[0052] Overall, with the arrangement described above, four different relative arrangements of the three unbalanced masses U1, U2, and U3 can be realized, which are shown in Figures 8A to 8D with decreasing overall eccentricity. Figures 9A to 9D show the generated vibrations or vibration amplitudes A1 to A4 at a common, defined rotational frequency or speed of the exciter shaft, each in a time-displacement diagram (SA corresponds to 9A, SB to 9B, 8C to 9C, and 8D to 9D). In practical use, with the arrangement shown, an operator can thus choose between the amplitudes A1 to A4 generated by the vibration exciter 2 by adjusting the relative positions of the unbalanced masses U1, U2, and U3. In addition, it can be provided that the speed of the excitation shaft 9 is also variable in oscillation operation in order to further vary the amplitude spectrum that can be generated.

[0053] Fig. 10 illustrates another alternative embodiment of a vibration exciter 2 in a perspective oblique view. In this embodiment, the linear guide 27 of the second imbalance mass U2 is provided, for example, by means of two guide axes 28 extending through the exciter shaft 9, which are guided through two through-bores 29 through the exciter shaft 9. The first and second end positions are defined by a guide frame 30 that rotates around the exciter shaft 9.

[0054] Fig. 11 shows a flow diagram of a method for adjusting a vibration amplitude of a vibration exciter 2 for a soil compaction device 1. For the method according to the invention, it is provided in a first step 31 that a rotation of the exciter shaft and, if present, the third unbalanced mass connected to the exciter shaft in a rotationally fixed manner takes place into one of two defined, preferably offset by 180' from one another, setting rotational positions or at least setting rotational position ranges. In step 32, a second unbalanced mass is then adjusted, in particular by gravity, into one of two defined end positions relative to the exciter shaft 9 depending on the setting rotational position to which the exciter shaft has been adjusted. Subsequently, in step 33, a direction of rotation of the exciter shaft is specified and the exciter shaft is accelerated into a rotational movement about a rotational axis of the exciter shaft in the direction of the specified direction of rotation.Finally, in step 34, a defined relative position of a first unbalanced mass is set from two defined possible relative positions of the first unbalanced mass relative to the third unbalanced mass depending on the current direction of rotation of the excitation shaft.

[0055] It can be provided that steps 31 to 34 are controlled and carried out automatically by a control unit. For this purpose, it can also be provided that an operator first selects one of at least three, in particular at least and especially exactly four operating modes or one of four displayable amplitudes is selected and the control unit carries out steps 31 to 34 depending on this,

[0056] The method as shown in Fig. 11 is particularly suitable for implementation with one of the vibration exciters 2 shown in the other figures.

Claims

PATENT CLAIMS 1. Vibration exciter (2) for a soil compaction device (1), comprising: - an excitation shaft (9) rotatable about a rotation axis (R), - a first unbalanced mass (U1) arranged eccentrically to the axis of rotation (R) of the exciter shaft (9), which is mounted on the exciter shaft (9) in such a way that it is rotatable within a reversal range relative to the exciter shaft (9) about a reversal axis (UA) running coaxially or parallel to the axis of rotation (R) of the exciter shaft (9) and can assume two different end positions depending on the direction of rotation (RI, R2) of the exciter shaft (9) relative to the exciter shaft (9), characterized in that a second unbalanced mass (U2) is provided which is mounted on the exciter shaft (9) and can be set in rotation about the axis of rotation (R) by the exciter shaft (9), which second unbalanced mass (U2) is adjustable between a first and a second end position independently of the direction of rotation (R1, R2) of the exciter shaft (9) relative to the axis of rotation (R) of the exciter shaft (9) and relative to the first unbalanced mass (U1).

2. Vibration exciter (2) according to claim 1, characterized in that a third unbalance mass (U3) is arranged eccentrically to the axis of rotation (R) of the exciter shaft (9) and is stationary relative to the exciter shaft (9).

3. Vibration exciter (2) according to one of the preceding claims, characterized in that the second unbalanced mass (U2) is mounted on the exciter shaft (9) and / or the third unbalanced mass (U3) via a linear guide (27), wherein the linear guide (27) is designed such that an adjustment of the second unbalanced mass (U2) between the first and the second end position takes place along a linearly extending adjustment axis.

4. Vibration exciter (2) according to claim 3, characterized in that the linear guide (27) has at least one of the following features: - it defines an adjustment axis which runs in the radial direction to the rotation axis (R); - it comprises at least one linear through-opening (29) in the exciter shaft (9) and a guide axis (28) which is fixedly connected to the second unbalanced mass (U2) and which runs through the linear through-opening (29); - it comprises two guide flanks (25) which are fixedly connected to the second unbalance mass (U2), lie opposite one another and run parallel to one another and are guided on an outer surface of the exciter shaft (9).

5. Vibration exciter (2) according to one of the preceding claims, characterized in that a rotation lock (35) is provided, which is designed such that the second unbalance mass (U2) is rotationally fixed relative to the rotation axis (R) of the exciter shaft (9), 6. Vibration exciter (2) according to one of the preceding claims, characterized in that the first and / or the second end position of the second unbalanced mass (U2) relative to the third unbalanced mass (U3) is fixed by a mechanical stop (21), in particular a stop (21) formed by the exciter shaft (9) itself.

7. Vibration exciter (2) according to one of the preceding claims, characterized in that the second unbalanced mass (U2) has a center of mass (M3), wherein the distance of the center of mass (M3) in the radial direction to the axis of rotation (R) of the exciter shaft (9) is greater in the first end position than in the second end position.

8. Vibration exciter (2) according to claim 7, characterized in that the center of mass (M3) of the second unbalanced mass passes through a virtual plane during an adjustment of the second unbalanced mass (U2) from the first end position to the second end position, in which the axis of rotation (R) of the exciter shaft (9) lies and which runs perpendicular to the adjustment direction of the second unbalanced mass (U2) between the first and the second end position.

9. Vibration exciter (2) according to one of claims 7 or 8, characterized in that it is designed such that the third unbalanced mass (U3) and the first unbalanced mass (U1) each have a center of mass (M1, M2), and that the first, the second and the second unbalanced mass (U2) are adjustable relative to one another such that when the second unbalanced mass (U2) is in at least one of the two end positions and the first unbalanced mass (U1) is in at least one of the two mutually different end positions, the centers of mass (M1, M2, M3) of the first, the second and the third unbalanced mass lie on a common straight line running in the radial direction to the axis of rotation (R).

10. Vibration exciter (2) according to one of the preceding claims, characterized in that the second unbalanced mass (U2) is mounted on the exciter shaft (9) in such a way that an adjustment of the second unbalanced mass (U2) from the first to the second end position relative to the third unbalanced mass (U3) takes place, in particular exclusively, by gravity.

11. Vibration exciter (2) according to one of the preceding claims, characterized in that a device (12) is provided for detecting at least two mutually different setting rotational positions of the exciter shaft (9).

12. Vibration exciter (2) according to one of the preceding claims, characterized in that a device (11) for selectively setting and maintaining at least the first and the second setting rotational position of the exciter shaft (9) is provided, wherein in the first setting rotational position an adjustment of the second unbalance mass (U2) into the first end position and in the second setting rotational position an adjustment of the second unbalance mass (U2) into the second end position relative to the third unbalance mass (U3) takes place.

13. Vibration exciter (2) according to one of the preceding claims, characterized in that a control unit (11) is provided which is designed such that, with a predetermined selection of an operating mode from at least three different possible operating modes dependent on a total eccentricity (EXS) of the vibration exciter (2), it at least - specifies a setting rotational position of the excitation shaft (9) and / or a direction of rotation of the excitation shaft (9) and / or - the assumption of a predetermined setting rotational position of the excitation shaft (9) and then the acceleration of the excitation shaft (9) in a predetermined direction of rotation are controlled in a time-dependent manner.

14. Vibration exciter (2) according to one of the preceding claims, characterized in that a sensor device (12) is provided which is designed to detect at least the assumption of one of the two different end positions by the first unbalanced mass (U1) and / or the assumption of the first and / or the second end position of the second unbalanced mass.

15. A method for adjusting a vibration amplitude of a vibration exciter (2) for a soil compaction device (1), in particular for a vibration exciter (2) according to one of claims 1 to 14, comprising the steps of a) rotating (31) an exciter shaft (9) about a rotation axis (R) into one of two defined, preferably 180° offset, set rotational positions; b) adjusting (32) a second unbalanced mass into one of two defined end positions depending on the set rotational position into which the exciter shaft (9) has been adjusted; c) specifying (33) a direction of rotation of the exciter shaft (9) and accelerating the exciter shaft (9) into a rotational movement about a rotation axis (R) of the exciter shaft (9) in the direction of the specified direction of rotation;d) setting (34) a defined relative position of a first unbalanced mass from two defined possible relative positions of the first unbalanced mass relative to the exciter shaft (9) depending on the current direction of rotation of the exciter shaft (9); 16. The method according to claim 15, characterized in that in step a) the current rotational position of the exciter shaft (9) is detected and, depending on the currently detected rotational position of the exciter shaft (9), the exciter shaft (9) is rotated further about the rotation axis (R) until the currently detected rotational position corresponds to the one defined rotational position.

17. Method according to one of claims 15 or 16, characterized in that the predetermined in steps a) to d) - one of two defined end positions of a second unbalanced mass relative to a third unbalanced mass and - one of two defined relative positions of the first unbalanced mass relative to a third unbalanced mass is achieved by selecting a desired total eccentricity from one of a total of at least three available and mutually different total eccentricities of the vibration exciter (2).

18. Method according to one of claims 15 to 17, characterized in that the adjustment of the second unbalance mass in step b) is carried out by gravity.

19. Method according to one of claims 15 to 18, characterized in that the reaching of the end positions in steps b) and / or d) takes place by a mechanical stop of the unbalanced mass and / or the first unbalanced mass on an adjustment stop.

20. Soil compaction device (1) with a vibration exciter (2) according to one of claims 1 to 14, characterized in that it is a soil roller, in particular a tandem roller or a roller train.

21. Soil compaction device (1) according to claim 20, characterized in that it has a control unit for carrying out the method according to one of claims 14 to 18.

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