Vibration generator for a soil compaction machine, method for adjusting the vibration amplitude of a vibration generator for a soil compaction machine, and soil compaction machine with a vibration generator

Abstract

Vibration exciter (2) for a soil compaction device (1), comprising: - an excitation wave (9) rotatable about an axis of rotation (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 relative to the exciter shaft (9) depending on the direction of rotation (R1, R2) of the exciter shaft (9), characterized in that a second unbalanced mass (U2) is provided which is mounted on the exciter shaft (9) and which can be rotated by it about the axis of rotation (R), and which 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).

Description

[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, as well as a soil compaction device equipped with such an exciter, are known, for example, from US 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 driven rotationally about an axis of rotation, on which at least one unbalanced mass is arranged eccentrically. An unbalanced mass in this sense can also be referred to as an unbalance weight or eccentric mass. Due to the imbalance caused by the eccentricity, vibrations usable for compaction are generated when the exciter shaft rotates.It is known to arrange at least one so-called counterweight (hereinafter referred to as the first unbalanced mass) on the exciter shaft. This counterweight is eccentrically designed and is adjustable between two end positions on the exciter shaft depending on the direction of rotation of the exciter shaft (i.e., the center of mass of the counterweight lies outside the axis of rotation). Furthermore, a second unbalanced mass (hereinafter referred to as the third unbalanced mass or exciter shaft weight) can be fixedly arranged on the exciter shaft. This second unbalanced mass always maintains the same relative position to the exciter shaft and is therefore unchangeable in its relative position. This exciter shaft weight can, for example, be manufactured in one piece together with the exciter shaft itself and be a single component consisting of a common body.The counterweight is rotationally decoupled from the excitation shaft and, if present, the excitation shaft weight attached to it, or is rotatable about an axis of rotation and can assume various angular positions relative to the excitation shaft and, if present, the excitation shaft weight within a rotation range limited, for example, by stops. The axis of rotation of the excitation shaft, possibly together with the excitation shaft weight, and the axis of rotation of the counterweight relative to the excitation shaft weight can be coaxial or parallel to each other, as described in EP 2 390 416 A2. The counterweight is repeatedly carried by the rotating excitation shaft from a lower position by means of a stop (or the like) to a kinematically determined tipping or overturning point, at which the counterweights tip over due to gravity (or inertia).The counterweight flips over and strikes a designated stop on the excitation shaft or excitation shaft weight from the opposite side. Depending on the direction of rotation of the excitation shaft, the counterweight can thus assume a position in which its unbalanced mass is added to the excitation shaft weight during rotation, or in which the center of mass of the combined counterweight and excitation shaft weight is further away radially from the axis of rotation of the excitation shaft, thereby 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 counterweight opposes the mass of the exciter shaft weight during rotation. This results in the center of mass of the combined counterweight and exciter shaft weight being closer together radially to the exciter shaft's axis of rotation, thus reducing the vibration amplitude. With this arrangement, two different amplitudes can be generated at the same absolute rotational speed, depending on the exciter shaft's direction of rotation. A disadvantage of this vibration exciter is that the vibration amplitude can only be adjusted between two modes depending on the direction of rotation.

[0003] Furthermore, continuously adjustable vibration exciters are known in the prior art, as described, for example, in DE 10 2010 010 037 A1. Such vibration exciters allow stepless adjustment of the amplitude within an adjustment range of the relative positions of the counterweight and the exciter shaft weight to each other. A disadvantage of these vibration exciters is that a comparatively complex and therefore costly adjustment mechanism is often required.

[0004] The vibration exciters relevant here are intended for use in soil compaction equipment, such as rollers, especially roller trains and tandem rollers. Examples of such soil compaction equipment are described, for instance, in DE 10 2019 002 439 A1, EP 0 945 187 A2, and DE 10 2012 017 777 A1. DE 102 53 570 A1 discloses a vibration exciter with an unbalanced mass non-rotatably connected to the exciter shaft, which is adjustable between a first and a second end position within an elongated hole. DE 10 2020 125 902 A1 discloses a vibration excitation device with a centrifugal adjusting element for adjusting the eccentric element depending on the rotational speed and / or centrifugal force acting on the eccentric element.

[0005] Starting from this, the object of the invention is to provide a constructively simple and comparatively cost-effective way to offer the operator of a soil compaction device with a vibration exciter more than two options regarding available vibration amplitudes.

[0006] The problem is solved using a vibration exciter, a method, and a soil compaction device according to one of the independent claims. Preferred embodiments 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 rotatable about a rotation axis, in particular a horizontal one. A drive unit with a drive motor, for example an internal combustion, electric, or hydraulic motor, can be provided to drive the rotational movement of the exciter shaft. The exciter shaft is connected to the drive motor directly or indirectly, in particular via a suitable drive transmission. The drive unit is designed such that the exciter shaft is driven to rotate in two different directions, 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 reversing gearbox arranged in the drive train between the drive motor and the exciter shaft.

[0008] The vibration exciter of this type comprises at least one first unbalanced mass arranged eccentrically to the axis of rotation of the exciter shaft. This first unbalanced mass is mounted on the exciter shaft such that, within a reversal range relative to the exciter shaft, it is rotatable about a reversal axis coaxial 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. The first unbalanced mass can be mounted, for example, on the exciter shaft and / or on an optional third unbalanced mass, which will be described in more detail below. This mounting can be achieved, for example, via a rotary bearing, in particular a plain bearing, consisting of a bearing bushing encompassed by the first unbalanced mass and a bearing shaft, such as the exciter shaft, guided through the bearing bushing. The bearing shaft's axis of rotation is parallel or coaxial to the axis of rotation of the exciter shaft.The first unbalanced mass, designed as a reversing 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 reversing axis that runs parallel but not coaxially to 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. To define the extent of the rotational or reversing movement of the first unbalanced mass relative to the exciter shaft within the intended rotation range, which is typically less than 190°, one or more stops can be provided. These stops cause the third unbalanced mass and / or the exciter shaft and the first unbalanced mass to abut each other in the direction of the current rotation.If the third unbalanced mass and / or the excitation 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 excitation shaft will carry the first unbalanced mass along with it as the rotation continues. The rotation of the first unbalanced mass can therefore preferably be driven exclusively and directly only by being carried along by the third unbalanced mass and / or the excitation shaft.

[0009] By definition, the center of mass (also 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 comprises a second unbalanced mass in addition to the first unbalanced mass. The second unbalanced mass is also mounted on the exciter shaft and is set into rotation about the axis of rotation by the shaft during vibration excitation operation, or rather, 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 therefore determined, at least substantially, by the entirety of at least the first and second unbalanced masses and the relative position of the first and second centers of mass to each other with respect to the axis of rotation.The second unbalanced mass is also adjustable between a first and a second end position relative to the excitation shaft. The two end positions of the second unbalanced mass differ in that the resulting unbalance or eccentricity of the second unbalanced mass with respect to the axis of rotation must be different, which is not required for the two end positions of the first unbalanced mass. During compression or vibration excitation operation, when the excitation shaft rotates around its axis of rotation at, for example, a defined speed, the second unbalanced mass can only assume and maintain one of the two end positions at any given time. The second unbalanced mass can be moved into the first or second end position independently of the first unbalanced mass and also independently of the direction of rotation of the excitation shaft.The adjustment, independent of the direction of rotation of the exciter shaft, relative to the axis of rotation of the exciter shaft and relative to any third unbalanced mass, is achieved in particular along a guide, especially along a linear guide running radially or obliquely to the axis of rotation. Ideally, the guide is designed such that not only are the first and second end positions of the second unbalanced mass relative to the exciter shaft clearly defined, but also, and especially, the adjustment path from the first end position to the second end position, particularly relative to the exciter shaft.The second unbalanced mass, which is adjustable between a first and second end position relative to the first unbalanced mass and the exciter shaft itself, is thus added to the vibration exciter in addition to the adjustable first unbalanced mass. The mechanisms that trigger and drive the adjustment of the first and second unbalanced masses relative to the exciter shaft are distinct and different from each other. Overall, this arrangement allows for at least three different relative positions of the centers of mass of the first and second unbalanced masses, each represented by two variable, defined end positions of the first and second unbalanced masses relative to the exciter shaft. The underlying drive mechanisms for the adjustment of the first and second unbalanced masses are also distinct.The operator thus has at least three vibration amplitudes available that can be generated by the vibration exciter, whereby it should be noted for the avoidance of doubt that this refers to the same rotational speed of the excitation shaft or the same vibration frequency. Furthermore, changing the vibration amplitude by changing the rotational speed of the excitation shaft or the frequency is also possible and is included in the invention.

[0011] The spectrum of amplitudes achievable 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 exciter shaft's axis of rotation and, unlike the first and second unbalanced masses, is fixedly connected to it. Ideally, the exciter shaft and the third unbalanced mass thus form a unit that is not adjustable relative to each other. Eccentricity refers to the center of mass (third center of mass) of the third unbalanced mass. The body assumed to represent the third unbalanced mass is therefore formed by the region(s) of the third unbalanced mass that lie eccentrically to the axis of rotation, but in particular also by the entirety of the exciter shaft and the first unbalanced mass.The third unbalanced mass and the excitation shaft can form a rigid, even monolithic, unit made of a single material. The relative position of the unbalanced mass to the excitation shaft is thus clearly defined and unchangeable during normal operation. By combining it with the first and second unbalanced masses and their adjustable positions between two defined end positions relative to the excitation shaft, and therefore also relative to the third unbalanced mass, a total of four relative positions of the three unbalanced masses can be generated. This results in four vibration amplitudes during vibration excitation operation, or when the excitation shaft is rotating around the axis of rotation.

[0012] The specific design of the guide for the second unbalanced mass between its two end positions can vary. However, it is preferred that the second unbalanced mass is mounted on the excitation shaft and / or the third unbalanced mass via a linear guide, the linear guide being designed such that the second unbalanced mass can be adjusted between its first and second end positions along a linearly extending adjustment axis. A linear guide is relatively easy to manufacture and results in more reliable movement in practical applications.

[0013] The linear guide is preferably designed such that it defines or has an adjustment axis extending radially to the axis of rotation. This 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 similar features, and a counter element, such as an axle, a sliding block, a bushing, a counter rail, etc., which slides along this axis. The movement axis preferably extends such that it perpendicularly intersects the axis of rotation of the exciter shaft. Additionally or alternatively, the movement axis preferably intersects both the second center of mass (i.e., the center of mass of the second unbalanced mass) and / or the axis of rotation of the exciter shaft.

[0014] The linear guide can additionally or alternatively include 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 passes through the linear through-hole. This solution is extremely compact, since a cavity passing through the exciter shaft is used to guide the second unbalanced mass.

[0015] The weakening of the exciter shaft's structural integrity associated with the through-hole can be particularly disadvantageous for compact yet very powerful vibration exciters. A further complementary or alternative design option for the linear guide is to incorporate two opposing, parallel guide flanks, fixed to the second unbalanced mass, which are guided along an outer surface of the exciter shaft. These guide flanks can, for example, be formed by the opposing longitudinal flanks of an elongated slot. In this variant, the second unbalanced mass is thus guided on the outside of the exciter shaft.To further secure the rotation of the second unbalanced mass on the exciter shaft, as described in more detail below, it may be additionally provided that the exciter shaft, in the contact area with the guide flanks, is longitudinally elongated, in particular oblong, deviating from its usual circular cross-section perpendicular to the axis of rotation, and thus has at least two parallel, planar sliding surfaces on its outer surface, which are in full contact with the corresponding mating surfaces of the guide flanks. The areas of the elongated hole connecting the guide flanks can serve as an adjustment stop or travel limiter.

[0016] To prevent the relative position of the second unbalanced mass from changing with respect to the excitation shaft and / or third unbalanced mass when the direction of rotation of the excitation shaft changes, it is advantageous for the vibration exciter to have a rotation lock designed such that the second unbalanced mass is at least substantially rotationally fixed relative to the axis of rotation of the excitation shaft. Rotationally fixed in this context does not mean that the second unbalanced mass is also stationary. A rotationally fixed arrangement of the first unbalanced mass and / or excitation shaft relative to the second unbalanced mass exists when no at least significant movement of the second unbalanced mass relative to the third unbalanced mass and / or the excitation shaft around the axis of rotation is possible.In a plane perpendicular to the axis of rotation, the second unbalanced mass can be adjusted relative to the third unbalanced mass and / or exciter shaft, for example, along a longitudinal adjustment curve or similar, but preferably exclusively linearly in a longitudinal direction. However, the anti-rotation device is preferably designed such that rotation of the second unbalanced mass relative to the third unbalanced mass and / or exciter shaft about the exciter shaft's axis of rotation is not possible, at least not to allow movement of the second unbalanced mass from its first to its second end position. The anti-rotation device 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 is carried along by it directly or indirectly via the anti-rotation device, even during a change of direction of rotation, without interruption.The anti-rotation device, as described here, 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 that it does not leave its achieved end position due to a change in the direction of rotation of the exciter shaft or become dependent on it, and thus shift into the opposite end position. However, this anti-rotation device does not preclude the possibility that the bearing of the second unbalanced mass on the exciter shaft and / or the third unbalanced mass has some play or even a comparatively small degree of freedom 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 based on the force of gravity acting upon 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 exciter. The rotational restraint is thus preferably designed such that it limits any possible adjustment of the second unbalanced mass relative to the exciter shaft and / or the third unbalanced mass about the axis of rotation of the exciter shaft to very few degrees, in particular to a range of less than 5°. The range of motion of the second unbalanced mass about the axis of rotation is therefore considerably smaller, for example by a factor of at least 15 or more, than the range of motion of the first unbalanced mass.

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

[0018] Preferably, the second unbalanced mass has a center of mass (second center of mass) whose distance in the radial direction to the rotation axis of the excitation wave 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 rotation axis with the two different end positions.

[0019] Ideally, the center of mass of the second unbalanced mass passes through a virtual reference plane when the second unbalanced mass is moved from the first end position to the second end position. This reference plane contains the axis of rotation of the excitation shaft and is perpendicular to the direction of adjustment (especially to an adjustment direction along a linear axis) of the second unbalanced mass between the first and second end positions.This ensures that, regardless of the rotational movement and / or direction of rotation of the excitation shaft, no centrifugal forces act on the second unbalanced mass that would displace it from its respective end position. This is because the center of mass is spaced away from the axis of rotation in each of the two end positions and, moreover, is clearly positioned with respect to this plane: for one end position, exclusively on one side of the plane (e.g., in front of the plane), and for the other end position, exclusively on the other side of the plane (e.g., behind the plane). In both cases, the centrifugal forces acting on the second unbalanced mass during rotation thus 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 by the fact that the second unbalanced mass is stabilized or locked by centrifugal force in both end positions during rotation of the exciter shaft. Additionally or alternatively, one or more locking devices may be provided that fix the second unbalanced mass in one or both end positions relative to the exciter shaft and / or third unbalanced mass. These can be, for example, mechanically, magnetically, and / or electromagnetically acting locking devices. Furthermore, it may also be provided that the adjustment of the second unbalanced mass relative to the third unbalanced mass and / or relative to the exciter shaft is effected 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 unbalanced masses has its own center of mass. Based on this, it can be advantageous if the first, second, and, if present, third unbalanced masses are adjustable relative to each other such that, when the second unbalanced mass is in at least one of its two end positions and the first unbalanced mass is in at least one of its two different end positions, the centers of mass of the first, second, and, if present, third unbalanced masses lie on a common straight line extending radially to the axis of rotation, particularly when projected onto a virtual reference plane to which the axis of rotation is perpendicular. Ideally, the arrangement of the two or three unbalanced masses should be such that...Three centers of mass on a common line, especially when projected onto a virtual reference plane to which the axis of rotation is perpendicular, exist in all possible configurations, for example, three or even four. In this way, the vibration exciter can generate the maximum and minimum possible total eccentricity for the individual unbalanced masses of the first, second, and, if applicable, third unbalanced masses, or, at a defined rotational speed, the maximum and minimum vibration amplitude, and one or two vibration amplitudes lying between these two.

[0021] It is advantageous if the second unbalanced mass is mounted on the exciter shaft in such a way that its movement from the first to the second end position relative to the exciter shaft and / or third unbalanced mass is, in particular, exclusively, driven by gravity. This can be achieved, in particular, by setting a specific rotational position of the exciter shaft in which, for example, a linear axis of movement of the second unbalanced mass relative to the exciter shaft and / or third unbalanced mass runs vertically (or at least almost vertically). Then, the second unbalanced mass can, for example, be guided vertically downwards from one of the two end positions to the other due to its own weight.If the second unbalanced mass is to assume the opposite end position, the excitation shaft must be rotated such that its current end position, viewed vertically, lies above the desired end position, specifically perpendicular to it. A separate drive for adjusting the second unbalanced mass is then unnecessary, as the drive required for the described rotation of the excitation shaft is already present. However, it is preferable if the excitation shaft drive allows for two different drive modes: specifically, a vibration excitation mode with a comparatively high speed and an "adjustment mode" for the second unbalanced mass with a comparatively low speed, or with the ability to rotate the excitation shaft by just a few degrees in one or the other direction.

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

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

[0024] For the practical application of the vibration exciter according to the invention, it is advantageous if it includes or is controlled by a control unit designed such that, for a predetermined selection of an operating mode, for example manually by an operator or automatically within the framework of a compression control system, it controls the assumption of the required relative positions of the first, second, and third unbalanced masses to each other from at least three, in particular four, different possible operating modes, which depend on or are predetermined by a total eccentricity of the vibration exciter. The eccentricity denotes the radial distance of the center of mass of the respective unbalanced mass to the axis of rotation. The total eccentricity, on the other hand, denotes the combined distance of the centers of mass of these three unbalanced masses.Ultimately, this means that at a constant rotational speed of the exciter shaft, increasing eccentricity results in an increased vibration amplitude, and vice versa. The control unit is preferably designed to specify at least one set rotational position of the exciter shaft and / or a direction of rotation of the exciter shaft. By controlling the set rotational position of the exciter shaft, the adjustment of the second unbalanced mass, particularly when gravity-driven, can be precisely controlled. Specifying a direction of rotation, on the other hand, defines the relative position of the first unbalanced mass to the exciter shaft and / or third unbalanced mass during rotation between their two end positions. Additionally or alternatively, the control unit can time the exciter shaft to assume a predetermined set rotational position and then accelerate the exciter shaft in a predetermined direction of rotation.This is advantageous because, for adjusting the second unbalanced mass, it is initially beneficial and important that the excitation shaft rotates only relatively slowly and / or even remains in the adjustment position for a certain period of time, so that the second unbalanced mass can be adjusted from one end position to the other. Subsequently, however, it is advantageous if the excitation shaft is accelerated rapidly, ideally abruptly, so that the dynamic forces acting on the second unbalanced mass ideally exceed the force of gravity acting on the second unbalanced mass within half a revolution, and preferably within a quarter revolution of the excitation shaft, in order to prevent the second unbalanced mass from "falling back".The rotational speed of the excitation shaft in vibration excitation operation is therefore considerably higher than the maximum possible rotational speed for adjusting the second unbalanced mass.

[0025] The vibration exciter preferably includes a sensor device designed to detect at least one of the two different end positions assumed by the first unbalanced mass and / or the assumption of the first and / or second end position of the second unbalanced mass. This can be achieved by direct and / or indirect detection of the respective end position. For example, contact sensors or non-contact sensors, optical, mechanical, or acoustic sensors, etc., can be used. The sensor data acquired by the sensor device can, in particular, be supplied to the control unit and / or the assumption of specific end positions detected 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 preceding information also applies to the inventive method. In a first step, an exciter shaft and, if present, a third unbalanced mass non-rotatably connected to the exciter shaft are rotated about an axis of rotation of the exciter shaft into one of two defined adjustment positions, preferably offset from each other by 180°. It is then provided that a second unbalanced mass is adjusted, in particular by gravity, into one of two defined end positions depending on the adjustment position into which the exciter shaft has been moved.This establishes the relative position of the second unbalanced mass with respect to the excitation shaft and / or the third unbalanced mass. A direction of rotation for the excitation shaft is then specified, and the excitation shaft is accelerated into a rotational motion around its axis of rotation in the specified direction. This results in the establishment of a defined relative position of the first unbalanced mass from two defined possible positions relative to the third unbalanced mass and / or the excitation shaft, depending on the current direction of rotation of the excitation shaft.For the adjustments of the first and second unbalance masses, a rotation of the excitation shaft is used in both cases, whereby in one case the achievement and at least short-term maintenance (or slow passing over) of a certain rotational position of the excitation shaft is decisive regardless of the direction of rotation of the excitation shaft, and in the other case the ideally comparatively rapid acquisition of the rotational movement in a certain direction of rotation of the excitation shaft is decisive.

[0027] In the first step, the current rotational position of the excitation shaft can be detected, and depending on this detected position, the excitation shaft can be rotated further around its axis of rotation until the detected position matches a defined position. This process can be automated and controlled by a control unit.

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

[0029] The reaching of the end positions in steps b) and / or d) is preferably achieved by mechanically striking the respective first unbalance mass and / or second unbalance 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 relates to a soil compaction device with a vibration exciter according to the invention. Such a soil compaction device can, for example, be a soil roller, in particular a tandem roller or a roller train. In the case of rollers, the vibration exciter is preferably arranged within a drum-shaped roller band that rolls on the soil to be compacted.

[0031] The soil compaction device according to the invention can include a control unit designed to carry out a method according to the invention.

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

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

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

[0035] Identical or similarly functioning components are identified in the figures by the same reference symbol. Repeating components are not numbered separately in each figure.

[0036] The Fig. Figures 1 and 2 show various soil compaction devices 1 with one or more vibration exciters 2 (each indicated by a dashed line) in side view. Each soil compaction device includes a soil contact device 3, through 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 contact device 3. For area soil compaction, the soil compaction devices 1 are moved in a forward and / or backward direction a across the subsoil, either by their own drive or at least partially by muscle power.

[0037] Fig. 1 is a self-propelled soil compaction machine 1 of the tandem roller type, in which the ground contact 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 driving force required for travel and operation is generated by a drive motor 6. The soil compaction machine 2 can be connected to the front and rear roller drums via a articulated steering system. An articulated version 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 one in Fig. The soil compaction device 1 shown is a roller compactor whose soil contact device 3 is a front roller drum, in the interior of which at least one vibration exciter 2 is arranged. The roller compactor 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 equipment 1 can be hand-operated and / or remotely controlled by an operator riding along with the soil compaction equipment 1.

[0040] Fig. Figure 3 shows 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 connected to the vibration exciter 2 via a drive train 8, here for example a belt drive, whereby a direct drive is also possible. The drive train 8 is connected at its output end to an exciter shaft 9, which is mounted within a housing 10 so as to be rotatable about an axis of rotation R. The drive train 8 and / or the drive motor 6 are designed such that the exciter shaft 9 can be rotated either clockwise or counterclockwise. This can be achieved directly by switching the drive direction of the drive motor 6 or via a reversing gearbox 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 into rotation. During vibration operation of the vibration exciter 2, all three unbalanced masses U1, U2, and U3 thus rotate together with the exciter shaft 9 around the axis of rotation R. It is understood that the respective unbalanced masses U1, U2, and U3 can be formed by a single component or by several components. The unbalanced masses U1, U2, and U3 thus each represent a cooperating unit with the functionalities described in more detail below. The unbalanced mass U3 can be formed as a single piece or even as a single unit with the exciter shaft 9.The unbalanced mass U1 is a so-called reversible weight, whose relative position to the unbalanced mass U3 is adjustable between two end positions depending on the direction of rotation of the excitation shaft 9 around the axis of rotation R. The unbalanced mass U2, on the other hand, is independent of the direction of rotation of the excitation shaft 9 between a first (in . Fig. 3 shown in a solid line) and a second (in Fig. 3 (U2' shown as a dashed line) end positions which differ from each other in their eccentricity, i.e., in their distance of their respective center of mass to the axis of rotation R, as described in more detail below.

[0041] The soil compaction device may include a control unit 11 designed for setting and / or controlling the adjustment options described below to provide different vibration amplitudes. It may also include a sensor device 12 for detecting one or more parameters relevant to setting and / or controlling these adjustment options. For this purpose, the sensor device 12 may, for example, include a rotation angle sensor 13, a rotation direction sensor 14, a rotation speed sensor 15, and a position sensor 16 for 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 excitation shaft 9. The control unit 11 may communicate with the sensor device 12.Furthermore, a display device 17, for example a monitor, and / or a selection device 18, for example an input keyboard, may be provided and be in signal communication with the control unit 11, via which a current operating mode can be displayed and / or selected.

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

[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 around the axis of rotation R at a radial distance from it. A receiving cup 20 can also be provided, as well as a rotation stop 21, which limits rotation relative 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 at a distance EX3 in the radial direction from the axis of rotation R. This distance EX3 denotes the eccentricity of the unbalanced mass U3. The excitation shaft 9 can be formed integrally with the unbalanced mass U3. In a partial area, the excitation shaft 9 has a section of radial guidance, for which purpose it has two opposing, linearly and parallel contact surfaces 26 and, for example, an oblong outer contour.The two mounting surfaces 26 are 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 therefore non-circular in cross-section perpendicular to the axis of rotation 09.

[0044] Fig. Figure 5B shows the first unbalanced mass U1 in a top view. This mass can, for example, be designed as a circular segment and, as part of a rotary bearing, include an exciter shaft passage opening 22. The center of mass of the first unbalanced mass U1 is designated M1. The first unbalanced mass U1 can also include two opposing stop flanks 23, 23', which can be designed to abut the rotary stop 21 of the third unbalanced mass U3.

[0045] The second unbalance mass according to Fig. 4C has a center of mass M2. A linear guide 27 is provided here by the opposing and parallel longitudinal flanks 25 of an elongated hole 24, which has an overall oblong contour in the plane of representation. The center of mass M2 lies in the elongated hole 24.

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

[0047] The Fig. 5A and Fig. Figure 5B illustrates 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 passage opening 22. When the exciter shaft 9 rotates counterclockwise in the direction of R1, the first unbalanced mass U1 strikes the rotation stop 21 with its side flank 23, and when the exciter shaft 9 rotates clockwise in the direction of R2, it strikes with its side flank 23'. Thus, depending on the direction of rotation R1 / R2, the unbalanced mass U1 strikes on different sides and is subsequently carried along by the exciter shaft 9 as the rotation continues in the respective direction.The adjustment movement of the first unbalanced mass U1 relative to the third unbalanced mass U3 and the excitation shaft (9) is opposite to the respective direction of rotation of the excitation shaft 9 and proceeds around the pivot axis UA, which in the present embodiment is coaxial with the axis of rotation R. The resulting two different relative positions of the centers of mass of the third unbalanced mass U3 and the first unbalanced mass U1 relative to each other allow the center of mass of the combined mass of both unbalanced masses U3 and U1 to be changed in its radial distance from the axis of rotation R. This enables the generation of two different vibration amplitudes at a defined rotational speed, depending on the direction of rotation.

[0048] In Fig. 6 is in addition to the arrangement from the Fig. 5A and Fig. 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 is non-circular in cross-section perpendicular to the axis of rotation R in the area where it passes through the elongated hole 24, rests positively against the longitudinal flanks 25 of the second unbalanced mass U2 with its opposing contact surfaces 25, thereby forming the linear guide 27, which allows adjustment of the second unbalanced mass U2 in the radial direction. Thus, unlike the first unbalanced mass U1, the second unbalanced mass U2, especially when the direction of rotation of the exciter shaft 9 is reversed, follows every rotational movement of the exciter shaft 9 in both directions and is positively guided against rotation. The longitudinal guide 27 therefore simultaneously forms a rotation lock 35 for the second unbalanced mass U2 relative to the third unbalanced mass U3 and the exciter shaft 9.At the same time, however, it is possible to adjust the second unbalanced mass U2 along the linear guide 27 formed by the elongated hole 24, in this case in the radial direction to the axis of rotation R. This can be achieved by a special drive element for adjustment or also depending 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, it is thus possible to adjust the relative position of the second unbalanced mass U2 with respect to the third unbalanced mass U3 and the exciter shaft 9, but in a different direction, namely in particular in the radial direction to the axis of rotation R (in ). Fig. 6 indicated by arrow C.

[0049] The Fig. 7A and Fig. 7B represents 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 into a stop position by its own weight. The second unbalanced mass U2 can be designed such that the second center of mass M2 not only changes its distance radially to 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, and in particular perpendicularly, to the adjustment direction of the second unbalanced mass U2 relative to the exciter shaft 9. This virtual plane is in the Fig. 7A and Fig. 7B is designated with H. This means that not only does the radial distance of the center of mass M2 of the second unbalanced mass U2 to the axis of rotation R differ in the two end positions, but also the side on which the second center of mass M2 is located relative to the exciter shaft 9, which then lies on opposite sides of this plane. This is advantageous because, 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, stabilizing it in its current relative position. Therefore, additional locking means that would fix the second unbalanced mass in one or both of its end positions, and which are generally possible and included in the invention, can be dispensed with.

[0050] The Fig. 7A and Fig. Figure 7B further illustrates that simply by assuming the two end positions of the second unbalanced mass U2, the radial distance of the overall mass center MS is changed. This is explained in the Fig. 7A and Fig. Figure 7B shows the positions of the centers of mass M1, M2, and M3 of the three unbalanced masses U1, U2, and U3. The overall center of mass MS of these three unbalanced masses results from the relative position of these three elements relative to the axis of rotation R. The arrangement of the three unbalanced masses U1, U2, and U3 in Fig. 7B the unbalance effect of the second unbalance mass U2 is added to the unbalance effect of the first and third unbalance masses U1 and U3, whereas the unbalance effect of the second unbalance mass U2 in the arrangement according to Fig. 7A minus the unbalance effect of the unbalance masses U1 and U3, since their center of mass M1 is located on the side opposite the other two centers of mass M2 and M3 relative to the 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 in Fig. 7A specifically smaller than in Fig. 7B.

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

[0052] In total, the arrangement described above allows for the realization of four different relative arrangements of the three unbalanced masses U1, U2 and U3, which are located in the Fig. Figures 8A to 8D are shown with decreasing overall eccentricity. Fig. Figures 9A to 9D show the generated vibrations or vibration amplitudes A1 to A4 at a common defined rotational frequency or speed of the excitation shaft in separate time-displacement diagrams (8A corresponds to 9A, 8B to 9B, 8C to 9C, and 8D to 9D). In practical application, an operator can thus select 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. Additionally, the rotational speed of the excitation shaft 9 can also be varied during vibration operation to further modify the achievable amplitude spectrum.

[0053] Fig. Figure 10 illustrates another embodiment of a vibration exciter 2 in a perspective oblique view. In this embodiment, the linear guidance 27 of the second unbalanced mass U2 is achieved, for example, by means of two guide axes 28 running through the exciter shaft 9, which are guided through two through-holes 29 in 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. Figure 11 shows a flowchart of a method for adjusting the vibration amplitude of a vibration exciter 2 for a soil compaction device 1. In the method according to the invention, a first step 31 involves rotating the exciter shaft and, if present, the third unbalanced mass non-rotatably connected to the exciter shaft into one of two defined adjustment positions, preferably offset by 180° from each other, or at least adjustment 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 adjustment position into which the exciter shaft has been moved. 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 an axis of rotation of the exciter shaft in the direction of the specified direction of rotation.Step 33 results in step 34 finally setting a defined relative position of a first unbalanced mass 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 may be provided that steps 31 to 34 are controlled and carried out automatically by a control unit. For this purpose, it may also be provided that an operator first selects one of at least three, in particular at least four, operating modes or one of four representable amplitudes via an input device, and that the control unit then carries out steps 31 to 34 depending on this selection.

[0056] The procedure, as in Fig. As shown in Figure 11, it is particularly suitable for use with one of the vibration exciters 2 shown in the other figures.

Claims

[1] Vibration exciter (2) for a soil compaction device (1), comprising: - an excitation wave (9) rotatable about an axis of rotation (R), - a first unbalanced mass (U1) arranged eccentrically to the axis of rotation (R) of the excitation shaft (9), which is mounted on the excitation shaft (9) in such a way that it is rotatable within a transition range relative to the excitation shaft (9) about a transition axis (UA) running coaxially or parallel to the axis of rotation (R) of the excitation shaft (9) and can assume two different end positions depending on the direction of rotation (R1, R2) of the excitation shaft (9) relative to the excitation shaft (9), characterized by, that a second unbalanced mass (U2) is mounted on the excitation shaft (9) and can be rotated by it around the axis of rotation (R), which is adjustable between a first and a second end position independently of the direction of rotation (R1, R2) of the excitation shaft (9) relative to the axis of rotation (R) of the excitation shaft (9) and relative to the first unbalanced mass (U1). [2] Vibration exciter (2) according to claim 1, characterized by , that a third unbalanced mass (U3) is arranged eccentrically to the axis of rotation (R) of the excitation shaft (9) and is stationary relative to the excitation shaft (9). [3] Vibration exciter (2) according to claim 2, characterized by, that the second unbalance mass (U2) is mounted on the excitation shaft (9) and / or the third unbalance mass (U3) via a linear guide (27), wherein the linear guide (27) is designed such that an adjustment of the second unbalance 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 by , that the linear guide (27) has at least one of the following features: - it defines an adjustment axis that runs radially to the rotation axis (R); - it includes at least one linear through-hole (29) in the excitation shaft (9) and a guide axis (28) fixedly connected to the second unbalance mass (U2), which runs through the linear through-hole (29); - it comprises two opposing, parallel guide flanks (25) which are fixedly connected to the second unbalance mass (U2) and are guided on an outer surface of the excitation shaft (9). [5] Vibration exciter (2) according to any one of the preceding claims, characterized by , that a rotation lock (35) is provided which is designed such that the second unbalance mass (U2) is rotationally fixed relative to the axis of rotation (R) of the excitation shaft (9). [6] Vibration exciter (2) according to one of claims 2 or 3, characterized by , that the first and / or the second end position of the second unbalanced mass (U2) relative to the third unbalanced mass (U3) is determined by a mechanical stop (21), in particular a stop (21) formed by the excitation shaft (9) itself. [7] Vibration exciter (2) according to any one of the preceding claims, characterized by, 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 excitation wave (9) is greater in the first end position than in the second end position. [8] Vibration exciter (2) according to claim 7, characterized by , that the center of mass (M3) of the second unbalanced mass passes through a virtual plane when the second unbalanced mass (U2) is adjusted from the first end position to the second end position, in which the axis of rotation (R) of the excitation 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 with one of claims 2, 3 or 6, characterized by, 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 (U1), the second (U2) and the third unbalanced mass (U3) are adjustable relative to each other 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 different end positions, the centers of mass (M1, M2, M3) of the first (U1), the second (U2) and the third unbalanced mass (U3) lie on a common straight line extending radially to the axis of rotation (R). [10] Vibration exciter (2) according to one of claims 2, 3, 6, 7, 8 or 9, characterized by, that the second unbalanced mass (U2) is mounted on the excitation 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) is, in particular, exclusively driven by gravity. [11] Vibration exciter (2) according to any one of the preceding claims, characterized by , that a device (12) is provided for detecting at least the assumption of two different adjustment rotational positions of the excitation shaft (9). [12] Vibration exciter (2) according to claim 11 with one of claims 2, 3, 6, 7, 8, 9 or 10, characterized by, that a device (11) for selectively adjusting and maintaining at least the first and second adjusting rotational positions of the excitation shaft (9) is provided, wherein in the first adjusting rotational position an adjustment of the second unbalance mass (U2) to the first end position and in the second adjusting rotational position an adjustment of the second unbalance mass (U2) to the second end position relative to the third unbalance mass (U3) takes place. [13] Vibration exciter (2) according to any one of the preceding claims, characterized by , that a control unit (11) is provided which is designed such that, for a given 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 - controls the assumption of a predetermined rotational position of the excitation shaft (9) and then the acceleration of the excitation shaft (9) in a predetermined direction of rotation over time. [14] Vibration exciter (2) according to any one of the preceding claims, characterized by , 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 (U2). [15] 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 any one of claims 1 to 14, comprising the steps a) Rotating (31) an excitation shaft (9) about an axis of rotation (R) into one of two defined, preferably 180° offset, setting rotation positions; b) Adjusting (32) a second unbalanced mass (U2) into one of two defined end positions depending on the adjustment rotational position into which the excitation shaft (9) has been adjusted, c) Specifying (33) a direction of rotation of the excitation wave (9) and accelerating the excitation wave (9) into a rotational motion about an axis of rotation (R) of the excitation wave (9) in the direction of the specified direction of rotation; d) Setting (34) a defined relative position of a first unbalanced mass (U1) from two defined possible relative positions of the first unbalanced mass (U1) relative to the excitation shaft (9) depending on the current direction of rotation of the excitation shaft (9). [16] Method according to claim 15, characterized by, that in step a) the current rotational position of the excitation shaft (9) is detected and, depending on the currently detected rotational position of the excitation shaft (9), the excitation shaft (9) is rotated further around the axis of rotation (R) until the currently detected rotational position matches the one defined rotational position. [17] Method according to one of claims 15 or 16, characterized by , that the one specified in steps a) to d) - one of two defined end positions of a second unbalanced mass (U2) relative to a third unbalanced mass (U3) and - one of two defined relative positions of the first unbalance mass (U1) relative to a third unbalance mass (U3) is achieved by selecting a desired total eccentricity from one of at least three available and mutually distinct total eccentricities of the vibration exciter (2). [18] Method according to any one of claims 15 to 17, characterized by, that the adjustment of the second unbalanced mass (U2) in step b) is gravity-driven. [19] Method according to any one of claims 15 to 18, characterized by , that the reaching of the end positions in steps b) and / or d) is achieved by mechanically striking the first unbalanced mass (U1) and / or the second unbalanced mass (U2) against an adjustment stop. [20] Soil compaction device (1) with a vibration exciter (2) according to one of claims 1 to 14, characterized by that it is a floor roller, in particular a tandem roller or a roller train. [21] Soil compaction device (1) according to claim 20, characterized by that it has a control unit for carrying out the method according to one of claims 15 to 19.

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