Vibration exciter for ground compacting equipment and ground compacting equipment having a vibration exciter

Abstract

The utility model relates to a kind of vibration exciters, it includes the exciter shaft that can rotate around rotation axis, the first unbalance mass that is eccentrically arranged relative to the rotation axis of exciter shaft, first unbalance mass is supported on exciter shaft, so that first unbalance mass can rotate within commutation range relative to exciter shaft around commutation axis coaxially with the rotation axis of exciter shaft or parallel extension and can according to the rotation direction of exciter shaft relative to exciter shaft occupy two different end positions, and including second unbalance mass, the second unbalance mass is supported on exciter shaft and can be placed in rotation around rotation axis by the exciter shaft, the second unbalance mass can be displaced relative to the rotation axis of exciter shaft and relative to first unbalance mass between first end position and second end position regardless of the rotation direction of exciter shaft. The utility model also relates to a ground compaction equipment with such vibration exciter and a method for adjusting the vibration amplitude of vibration exciter.

Description

Technical Field

[0001] This utility model relates to a vibration exciter for ground compaction equipment and a ground compaction equipment having a vibration exciter. Background Technology

[0002] For example, US7059802B1 discloses a vibration exciter for a ground compaction device and a ground compaction device equipped with the vibration exciter. To improve the compaction effect of the ground compaction device shown, compaction rollers are vibrated during the compaction process. Vibration is generated by one or more vibration exciters. The vibration exciter includes an exciter shaft that rotates about a rotation axis, on which at least one unbalanced mass is eccentrically disposed. In the present sense, the unbalanced mass may also be referred to as an unbalanced counterweight or an eccentric mass. Due to the imbalance caused by eccentricity, vibration useful for compaction is generated when the exciter shaft rotates. For this purpose, it is known to provide at least one so-called reversing counterweight (hereinafter referred to as the first unbalanced mass) on the exciter shaft, which is eccentrically constructed and supported on the exciter shaft in a manner that allows it to be moved between two end positions according to the rotation direction of the exciter shaft (i.e., the center of mass of the reversing counterweight is located outside the rotation axis). Furthermore, another unbalanced mass (hereinafter referred to as the third unbalanced mass or actuator shaft counterweight) may be fixedly positioned on the actuator shaft, always occupying the same relative position with respect to the actuator shaft, and therefore its relative position with respect to the actuator shaft cannot be changed. Thus, this actuator shaft counterweight may, for example, be manufactured as a single piece with the actuator shaft itself and be a unique component consisting of a common body. The reversing counterweight is rotationally decoupled from the actuator shaft and any actuator shaft counterweights (if present) arranged on it, or in other words, can rotate about the axis of rotation, and can occupy different angular positions relative to the actuator shaft and actuator shaft counterweights (if present) within a range of rotation limited (e.g. by a stop). The axis of rotation of the actuator shaft (if necessary, together with the actuator shaft counterweight) and the axis of rotation of the reversing counterweight relative to the actuator shaft counterweight may extend coaxially with each other, or may be parallel and offset from each other, as described in EP2390416A2. The reversing counterweight is repeatedly driven from a low position by the rotating actuator shaft via a stop (or similar) until a kinematically determined reversing or tipping point, at which the reversing counterweight tipps or reverses due to gravity (or inertia) and impacts the actuator shaft or the stop provided for this purpose on the actuator shaft or actuator shaft counterweight from the opposite side. Therefore, depending on the direction of rotation of the actuator shaft, the reversing counterweight can occupy a position where the unbalanced mass of the reversing counterweight is superimposed on the actuator shaft counterweight during rotational motion; or, in other words, the center of mass of the reversing counterweight and the actuator shaft counterweight as a whole is farther radially from the axis of rotation of the actuator shaft, thus increasing the vibration amplitude. Alternatively, when the exciter shaft rotates in the opposite direction, it can be in another position where the mass of the reversing counterweight acts in opposition to the mass of the exciter shaft counterweight during the rotation of the exciter shaft, so that the center of mass of the reversing counterweight and the exciter shaft counterweight as a whole is closer to the axis of rotation of the exciter shaft in the radial direction, thereby reducing the vibration amplitude.Therefore, with this arrangement, at the same absolute rotational speed, two different vibration amplitudes can be generated depending on the direction of rotation of the exciter shaft. The disadvantage of this vibration exciter is that the vibration amplitude can only be adjusted between the two modes according to the direction of rotation.

[0003] Furthermore, so-called continuously variable vibration exciters are known in the prior art, for example, as described in DE102010010037A1. Such vibration exciters enable continuous adjustment of the vibration amplitude within the range of adjustment of the relative position of the reversing counterweight and the exciter shaft counterweight. A disadvantage of such vibration exciters is that they often require relatively complex and therefore expensive adjustment mechanisms.

[0004] The vibration exciter settings described herein are intended for use in ground compaction equipment, such as, in particular, roller mills, especially single-drum and double-drum rollers. Examples of such ground compaction equipment are described, for example, in DE102019002439A1, EP0945187A2 and DE102012017777A1. Utility Model Content

[0005] Therefore, the purpose of this utility model is to provide a feasible solution with a structure that is as simple as possible and relatively cost-effective, offering operators of ground compaction equipment with vibration exciters more than two options for available vibration amplitudes.

[0006] The objective is achieved by a vibration exciter and a ground compaction device according to the present invention.

[0007] In a first aspect, the present invention relates to a vibration exciter for ground compaction equipment. The vibration exciter includes an exciter shaft rotatable about (particularly horizontally extending) a rotation axis. To drive the rotational movement of the exciter shaft, a drive device with a drive motor (e.g., an internal combustion engine motor, an electric motor, or a hydraulic motor) may be present, the exciter shaft being directly or indirectly (particularly via a suitable drive transmission mechanism) driven by the drive motor. The drive device is configured such that the exciter shaft is driven to rotate in two different directions of rotation (thus specifically clockwise and counterclockwise). This can be achieved directly by reversing the drive direction of the output shaft of the drive motor, or, for example, by a switching transmission mechanism disposed in the power transmission system between the drive motor and the exciter shaft.

[0008] Such vibration exciters include at least one first unbalanced mass eccentrically positioned relative to the axis of rotation of the exciter shaft. This first unbalanced mass is supported on the exciter shaft such that it can rotate relative to the exciter shaft within a reversing range about a reversing axis that extends coaxially or parallel to the axis of rotation of the exciter shaft, and can occupy two different end positions relative to the exciter shaft depending on the direction of rotation of the exciter shaft. For this purpose, the first unbalanced mass can be supported on the exciter shaft, for example, via a rotating bearing (particularly a sliding bearing), and / or optionally on a third unbalanced mass, as described in more detail below. The rotating bearing consists of a bearing bushing included by the first unbalanced mass and a bearing axis, such as the exciter shaft, guided by the bearing bushing, the axis of rotation of which extends parallel or coaxially to the axis of rotation of the exciter shaft. The first unbalanced mass, configured as a counterweight, has its own center of mass (first center of mass). Due to the given portability of the first unbalanced mass relative to, for example, a third unbalanced mass, and / or due to the use of a reversing axis that extends on a different axis than the axis of rotation of the actuator shaft, the radial distance between the center of mass of the first unbalanced mass and the line of rotation can be changed by altering the direction of rotation of the actuator shaft, and thus the eccentricity can be changed between two values. To enable the range of rotational or reversing motion of the first unbalanced mass relative to the actuator shaft to be defined within a predetermined rotational region (generally including less than 190°), one or more stops can be provided, through which the third unbalanced mass and / or the actuator shaft abuts against the first unbalanced mass in the direction of the current rotation. If the third unbalanced mass and / or the excitation shaft abuts against the first unbalanced mass in the direction of the current rotation, the third unbalanced mass and / or the excitation shaft drives the first unbalanced mass as it continues to rotate. Therefore, the rotational motion of the first unbalanced mass is preferably driven only by and directly by being driven only by the third unbalanced mass and / or the excitation shaft.

[0009] By definition, the center of mass (also called the center of mass, center of weight, or center of gravity) of a corresponding unbalanced mass is specifically the mass-weighted average of the positions of the points of mass that make up the corresponding unbalanced mass.

[0010] The key to this invention lies in the fact that the vibration exciter according to this invention, in addition to the first unbalanced mass, also has a second unbalanced mass. This second unbalanced mass is also supported on the exciter shaft and is placed in rotation about the axis of rotation by the exciter shaft during vibration excitation operation, or is driven into the rotational motion of the exciter shaft. The second unbalanced mass also has its own center of mass (second center of mass). Therefore, the overall center of mass of the unbalanced device driven by the exciter shaft, and thus the resulting outward eccentricity, is at least substantially determined by the combination of the first and second unbalanced masses and the relative positions of the first and second centers of mass with respect to the axis of rotation. The second unbalanced mass can also be shifted relative to the exciter shaft between a first end position and a second end position, wherein the two end positions of the second unbalanced mass are different from each other in such a way that the unbalance or eccentricity generated by the second unbalanced mass about the axis of rotation must be different from each other, which is not necessary for the two end positions of the first unbalanced mass. In compression operation or vibration-excited operation, when the actuator shaft rotates about its axis of rotation at, for example, a specified speed, the second unbalanced mass can only occupy and remain in one of the two end positions. The second unbalanced mass can be placed in the first end position or the second end position independently of the first unbalanced mass and also independently of the direction of rotation of the actuator shaft. The displacement of the second unbalanced mass relative to the axis of rotation of the actuator shaft and relative to the third unbalanced mass, which may be present if necessary, is carried out particularly along a guide structure, especially along a linear guide structure extending radially or obliquely relative to the axis of rotation. The guide structure is ideally constructed such that not only are the first and second end positions of the second unbalanced mass relative to the actuator shaft defined unilaterally, but also, particularly, the displacement path from the first end position to the second end position, especially the displacement path relative to the actuator shaft, is defined unilaterally. Therefore, by means of a second unbalanced mass (which can be displaced relative to the first unbalanced mass and between a first end position and a second end position relative to the actuator shaft, independent of the rotation direction of the actuator shaft), an additional displaceable unbalanced mass is added to the vibration actuator, in addition to the displaceable first unbalanced mass. The mechanisms for triggering and driving the displacement of the first and second unbalanced masses relative to the actuator shaft are distinct and different from each other. In summary, this arrangement allows for at least three different relative positions of the centroids of the first and second unbalanced masses via two variable, defined end positions for each of the first and second unbalanced masses, wherein the drive mechanisms upon which the displacement of the first and second unbalanced masses is based are different from each other. Therefore, the operator has a total of at least three vibration amplitudes that can be generated by the vibration actuator, which, it should be noted, involve the same rotational speed or the same vibration frequency of the actuator shaft. Furthermore, it is also feasible and included in this invention to change the vibration amplitude by altering the rotational speed or frequency of the actuator shaft.

[0011] If a third unbalanced mass, in the form of a counterweight on the exciter shaft, is present in addition to the first and second unbalanced masses, the amplitude spectrum provided by the vibration exciter according to this invention can be further altered. The third unbalanced mass is also eccentrically positioned on the exciter shaft relative to its axis of rotation, and unlike the first and second unbalanced masses, it is fixedly connected to the exciter shaft. Therefore, the exciter shaft and the third unbalanced mass ideally form a unit that is immovable relative to each other. Here, "eccentric" refers to the center of mass (third center of mass) of the third unbalanced mass. Thus, the object considered to be the third unbalanced mass is formed by one or more regions of the third unbalanced mass eccentrically positioned relative to its axis of rotation, but in particular, it is also constituted by the exciter shaft and the first unbalanced mass as a whole. The third unbalanced mass and the exciter shaft can be rigid in themselves, or even a single piece made of uniform material. Therefore, the relative position of the unbalanced mass relative to the exciter shaft is uniquely determined and cannot be changed during prescribed operation. By combining with the first and second unbalanced masses and their feasible repositionability relative to the actuator shaft and therefore also relative to the third unbalanced mass between each of the two defined end positions, it is possible to generate a total of four relative positions of the three unbalanced masses to each other and thus generate a total of four vibration amplitudes during vibration excitation operation, or in the case of the actuator shaft rotating about the axis of rotation.

[0012] The specific configuration of the guide structure for the second unbalanced mass between its two end positions can vary. However, it is preferred that the second unbalanced mass is supported on the actuator shaft and / or the third unbalanced mass via a linear guide structure, wherein the linear guide structure is configured such that the displacement of the second unbalanced mass between the first and second end positions proceeds along a linearly extending displacement axis. The linear guide structure is relatively easy to manufacture and enables a more reliable motion process in practical use.

[0013] The linear guide structure is preferably configured such that it defines or has a displacement axis extending radially relative to the axis of rotation, wherein the displacement axis is a motion axis and is formed, for example, through one or more sliding guides, guide rails, slots, holes, one or more elongated holes, etc., and mating elements (e.g., shafts, sliders, bushings, mating guide rails, etc.) that are guided to slide along it. The motion axis preferably extends such that it intersects perpendicularly with the axis of rotation of the actuator shaft. Additionally or alternatively, the motion axis preferably intersects not only the second center of mass (i.e., the center of mass of the second unbalanced mass) and / or the axis of rotation of the actuator shaft.

[0014] The linear guide structure may also supplementarily or alternatively include: at least one through-hole extending linearly along its longitudinal axis in the actuator shaft and a guide shaft fixedly connected to the location of the second unbalanced mass, the guide shaft extending through the linear through-hole. This solution is extremely compact because it uses a cavity through the actuator shaft to guide the second unbalanced mass.

[0015] However, the weakening of the structural integrity of the actuator shaft caused by the through-hole can be particularly disadvantageous in compact and high-power vibration actuators. Another supplementary or alternative feasible configuration for the linear guide structure now lies in that the linear guide structure includes two guide sidewalls fixedly connected to the second unbalanced mass, extending opposite and parallel to each other, and guiding on the outer surface of the actuator shaft. The guide sidewalls can, for example, be formed by opposing longitudinal sidewalls of an elongated hole. In this variant, the second unbalanced mass is thus guided on the outside of the actuator shaft. To prevent the second unbalanced mass from rotating on the actuator shaft, as will be described in more detail below, it can be further specified that the actuator shaft, in the area abutting the guide sidewalls, is constructed as an elongated, particularly rectangular, shape, unlike its generally circular configuration in cross-section perpendicular to the axis of rotation, and therefore has at least two parallel, flat sliding surfaces on its outer surface that are in planar contact with the corresponding mating surfaces of the guide sidewalls. The area where the elongated hole connects the guide sidewalls can be used as a displacement stop or a displacement path restriction.

[0016] To prevent the relative position of the second unbalanced mass with respect to the actuator shaft and / or the third unbalanced mass from changing when the direction of rotation of the actuator shaft changes, it is advantageous that the vibration actuator has an anti-rotation structure configured such that the second unbalanced mass cannot rotate relative to the axis of rotation of the actuator shaft, at least substantially. Here, "cannot rotate relative to each other" does not mean that the second unbalanced mass is also fixed in position. When at least noteworthy movement of the second unbalanced mass relative to the third unbalanced mass and / or the actuator shaft about the axis of rotation is not feasible, there is an arrangement in which the first unbalanced mass and / or the actuator shaft cannot rotate relative to each other with respect to the second unbalanced mass. Therefore, in a plane perpendicular to the axis of rotation, the second unbalanced mass can be completely displaced relative to the third unbalanced mass and / or the actuator shaft, for example, along a displacement curve extending longitudinally, but preferably only linearly along the longitudinal direction. However, the anti-rotation structure is preferably configured such that rotation of the second unbalanced mass relative to the third unbalanced mass and / or the actuator shaft, about the axis of rotation of the actuator shaft, is infeasible, at least not for realizing movement of the second unbalanced mass from its first end position to its second end position. The anti-rotation structure is configured such that the second unbalanced mass follows the rotational movement of the actuator shaft about the axis of rotation in two feasible rotational directions, or that the second unbalanced mass is continuously driven directly or indirectly by the anti-rotation structure even if the rotational direction changes. In the current scenario, the anti-rotation structure is essentially used to ensure that the second unbalanced mass is driven in both rotational directions of the actuator shaft in its respective end position and does not leave its respective reached end position and move to the other end position due to or unrelated to a change in the rotational direction of the actuator shaft. However, this anti-rotation structure does not preclude the second unbalanced mass from having clearance in its support on the actuator shaft and / or the third unbalanced mass, or even having relatively small degrees of freedom of movement in and against the rotational direction of the actuator shaft. This is particularly desirable and helpful when the second unbalanced mass should be displaced between its end positions solely by gravity acting upon it (as described in more detail below), and / or the second unbalanced mass bounces relative to the actuator axis and / or the third unbalanced mass in the direction of rotation and / or against the direction of rotation, in order to, for example, counteract torsional vibrations occurring within the vibrating actuator. Therefore, the anti-rotation structure is generally preferably constructed such that it limits the possible displacement of the second unbalanced mass relative to the actuator axis and / or the third unbalanced mass about the axis of rotation of the actuator axis to a very small extent, particularly less than 5°. Thus, about the axis of rotation, the free space of motion of the second unbalanced mass is particularly significantly smaller than that of the first unbalanced mass, for example, by at least a factor of 15 or more.

[0017] The positions of the second unbalanced mass relative to the first and / or second ends of the actuator shaft and / or the third unbalanced mass can be determined by mechanical stops, particularly by stops formed by the actuator shaft itself and / or the third unbalanced mass. These stops can be damped, but are preferably undamped. The same applies to the two end positions of the first unbalanced mass.

[0018] The second unbalanced mass has a center of mass (second centroid) that, compared to the second end position, is further in the radial direction from the axis of rotation of the actuator shaft in the first end position. This allows for two different eccentricities relative to the axis of rotation to be generated at the two different end positions.

[0019] The specification stipulates that when the second unbalanced mass is moved from the first end position to the second end position, the center of mass of the second unbalanced mass passes through a virtual reference plane in which the axis of rotation of the actuator shaft lies, and this virtual reference plane extends perpendicularly to the direction of movement of the second unbalanced mass between the first and second end positions (specifically, the direction of movement along a straight axis). This ensures that, regardless of the rotational motion and / or direction of rotation of the actuator shaft, no centrifugal force acts on the second unbalanced mass, which would displace the second unbalanced mass from its respective end position, because the center of mass in each of these two end positions is spaced apart from the axis of rotation, and the center of mass is specifically positioned with respect to this plane only on one side of the plane (e.g., in front of the plane) for one end position and only on the other side of the plane (e.g., behind the plane) for the other end position. In both cases, the centrifugal force acting on the second unbalanced mass during rotation is thus stably applied to the respective end position (ideally in conjunction with an anti-rotation structure and / or a longitudinal guide structure). Therefore, this further improvement is characterized in that the second unbalanced mass is stabilized or locked by centrifugal force during the rotational operation of the actuator shaft at both end positions. Additionally or alternatively, one or more locking devices may be present, which fix the second unbalanced mass in one or both end positions relative to the actuator shaft and / or the third unbalanced mass. This can be, for example, a locking device that operates mechanically and / or magnetically and / or electromagnetically. Furthermore, it may be additionally or alternatively specified that the displacement of the second unbalanced mass relative to the third unbalanced mass and / or relative to the actuator shaft is achieved by means of a motor-driven device (e.g., a spindle drive or similar device). However, purely gravity-driven displacement without additional locking devices 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 is advantageous that the first, second, and (if present) third unbalanced masses be displaced relative to each other such that when the second unbalanced mass is located in at least one of the two end positions and the first unbalanced mass is located in at least one of the 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 relative to the axis of rotation, especially when projected onto a virtual reference plane extending perpendicularly to the axis of rotation. Ideally, in all (e.g., three or even four) feasible configurations, there exists an arrangement where the two or three centers of mass lie on a common straight line, especially when projected onto a virtual reference plane extending perpendicularly to the axis of rotation. In this way, the vibration exciter can produce maximum and minimum feasible total eccentricity for the individual unbalanced masses of the first, second, and, if necessary, third unbalanced masses, or, at a defined rotational speed, maximum and minimum vibration amplitudes and one or two vibration amplitudes between these two amplitudes.

[0021] Advantageously, the second unbalanced mass is supported on the actuator shaft such that the displacement of the second unbalanced mass relative to the actuator shaft and / or the third unbalanced mass from the first end position to the second end position is gravity-driven, particularly gravity-driven only. This can be achieved, in particular, by setting a specific rotational position of the actuator shaft in which, for example, the axis of motion of the second unbalanced mass relative to the actuator shaft and / or the third unbalanced mass extends vertically (or at least almost vertically). Then, the second unbalanced mass, due to its own weight, can be guided vertically downwards from one of the two end positions to the other end position. If the second unbalanced mass is to occupy the corresponding other end position, the actuator shaft must be rotated for this purpose such that, viewed vertically, the current end position of the second unbalanced mass is above, and particularly perpendicular to, the end position to be occupied. Since the drive mechanism required for the described rotational movement of the actuator shaft already exists, no separate drive mechanism is needed for the possible displacement of the second unbalanced mass. However, it is preferable that the drive mechanism of the exciter shaft can achieve two different drive modes, specifically, a vibration excitation mode with a relatively high rotational speed and an "adjustment mode" for the second unbalanced mass, which has a relatively low rotational speed or the possibility of selectively rotating the exciter shaft by only a few degrees in one rotational direction and / or another.

[0022] Particularly advantageous for the gravity-driven displacement of the second unbalanced mass from one end position to the other is that the vibration exciter includes means for detecting at least one, particularly two, different adjustment rotational positions of the exciter shaft. These adjustment rotational positions, or the two adjustment rotational positions, can be designed such that the axis of motion of the second unbalanced mass between the two end positions extends vertically perpendicular to the horizontal plane. For example, the detection of the exact rotational position of the exciter shaft relative to the bearing structure that rotates the exciter shaft can be determined by means of a rotation angle sensor (especially a non-contact rotation angle sensor). Alternatively or supplementarily, it is also possible to detect the actual displacement movement of the second unbalanced mass, for example by means of a contact sensor or the like, and thereby detect the rotational position required for the displacement of the second unbalanced mass by the exciter shaft. Furthermore, when the displacement of the actuator shaft is relatively slow, the slippage of the second unbalanced mass can also be detected indirectly, for example by acoustic means (e.g., by impact noise caused by the second unbalanced mass when it reaches the desired end position), by the pressure fluctuations thus generated on the hydraulic motor, and / or by the voltage fluctuations thus generated on the electric motor.

[0023] Additionally or alternatively, it is also feasible to provide an additional driver configured solely for shifting the exciter shaft to at least one, particularly a specific, rotational position in which the second unbalanced mass transitions from its current end position to a corresponding other end position. Thus, the vibration exciter may include, for example, a dedicated control device for selectively adjusting and maintaining at least the first and second adjusted rotational positions of the exciter shaft, wherein in the first adjusted rotational position, a shift of the second unbalanced mass relative to a third unbalanced mass to a first end position occurs; and in the second adjusted rotational position, a shift of the second unbalanced mass relative to a third unbalanced mass to a second end position occurs.

[0024] For practical use of the vibration exciter according to this invention, it is advantageous to include or be controlled by a control unit, which is configured such that when an operating mode is pre-selected from at least three, particularly four, different operating modes depending on the total eccentricity of the vibration exciter, or a pre-given feasible operating mode (e.g., manually selected by the operator or automatically selected within the scope of compression control), the control unit controls the occupancy of the first, second, and second unbalanced masses with respect to their respective desired relative positions. Eccentricity here refers to the distance of the center of mass of the corresponding unbalanced mass radially to the axis of rotation. Total eccentricity refers to the distance of the common center of mass of the three unbalanced masses. Therefore, ultimately at a constant rotational speed of the exciter shaft, the vibration amplitude increases with increasing eccentricity, and vice versa. The control unit is now preferably configured such that it pre-given the adjustment rotational position and / or the direction of rotation of the exciter shaft. By controlling the adjustment rotational position of the exciter shaft, the second unbalanced mass can be selectively displaced, especially when the second unbalanced mass is driven by gravity. By specifying the direction of rotation, the relative position of the first unbalanced mass with respect to the exciter shaft and / or the third unbalanced mass between its two end positions during rotational operation can be determined. Supplementally or alternatively, the control unit can control the time-varying occupation of the exciter shaft at a pre-given adjustment rotational position and then control the acceleration of the exciter shaft in the pre-given direction of rotation. This is advantageous in this respect because it is first and foremost advantageous for the displacement of the second unbalanced mass that the exciter shaft rotates only relatively slowly and / or even maintains a specific time window in the adjustment rotational position so that the displacement of the second unbalanced mass from one end position to the other can be truly carried out. However, it is subsequently important that the exciter shaft accelerates rapidly (ideally abruptly) so that the centrifugal force acting on the second unbalanced mass ideally exceeds the gravity acting on the second unbalanced mass within half a revolution of the exciter shaft (particularly preferably within a quarter revolution of the exciter shaft) to prevent the second unbalanced mass from "falling back." Therefore, during vibration excitation operation, the rotational speed of the exciter shaft is significantly higher than the maximum possible rotational speed for the displacement of the second unbalanced mass.

[0025] The vibration exciter preferably has a sensor device configured to detect at least: the occupancy of a first unbalanced mass at one of the two distinct end positions and / or the occupancy of a second unbalanced mass at the first end position and / or the second end position. This can be achieved by directly and / or indirectly detecting the corresponding end positions. For example, contact or non-contact sensors, optical, mechanical, or acoustic sensors, etc., can be used for this purpose. The sensor data determined by the sensor device can be transmitted, in particular, to a control unit, and / or the occupancy of a specific end position determined by the sensor device can also be displayed on a display device.

[0026] This invention enables the implementation of a method for adjusting the vibration amplitude of a vibration exciter according to the invention for use in ground compaction equipment. The above description applies to the method, focusing on the details of the vibration exciter according to the invention. In a first step, the exciter shaft and a third unbalanced mass (if present) connected to the exciter shaft in a rotationally inverse manner about the axis of rotation of the exciter shaft are rotated to one of two defined adjustment rotation positions, preferably offset from each other by 180°. Then, depending on the adjustment rotation position to which the exciter shaft has been moved, a second unbalanced mass is moved to one of the two defined end positions, particularly by gravity-driven movement. Thus, the relative position of the second unbalanced mass with respect to the exciter shaft and / or the third unbalanced mass is defined. The direction of rotation of the exciter shaft is now predetermined, and the exciter shaft is accelerated into a rotational motion about the axis of rotation of the exciter shaft in the predetermined direction of rotation. This results in the adjustment of a defined relative position of the first unbalanced mass from two defined feasible relative positions of the first unbalanced mass relative to the third unbalanced mass and / or the actuator shaft, based on the current rotation direction of the actuator shaft. For the displacement of the first and second balancing masses, therefore more precisely, rotation of the actuator shaft is used in both cases, wherein in one case, reaching and at least briefly maintaining (or passing through) a specific rotational position of the actuator shaft regardless of its rotation direction is decisive, while in the other case, ideally, relatively rapidly initiating rotational motion along a specific rotational direction of the actuator shaft is decisive.

[0027] In the first step, the current rotational position of the actuator shaft can also be detected, and based on the currently detected rotational position, the actuator shaft can be further rotated around the rotation axis until the currently detected rotational position matches the defined rotational position. This can be automatically controlled and adjusted by the control unit.

[0028] The desired total eccentricity (or vibration amplitude) can be achieved by selecting one of two defined end positions of the 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 actuator shaft and (if present) the third unbalanced mass, as pre-defined by the method. This can be achieved by selecting one of at least three (especially exactly four) available and mutually different total eccentricities (or vibration amplitudes of the actuator shaft at defined rotational speeds) of the vibration actuator. This can be done manually or automatically.

[0029] In steps b) and / or d), reaching the end position is preferably achieved by mechanically stopping the corresponding first unbalanced mass and / or second unbalanced mass on the shift stop, wherein a shift stop can be provided for each of the end positions.

[0030] Finally, one aspect of this invention also relates to a ground compaction device having a vibration exciter according to this invention. Such a ground compaction device can be, for example, a road roller, particularly a twin-drum or single-drum road roller. For a road roller, the vibration exciter is preferably arranged within a drum-shaped roller drum that rolls on the ground to be compacted.

[0031] The ground compaction equipment according to this invention may include a control unit designed to implement the method.

[0032] Alternatively, the ground compaction equipment may have two or more vibration exciters according to this invention.

[0033] Alternatively or supplementarily, the individual unbalanced masses of the vibration exciter can also be arranged as multiple sub-units distributed along the exciter axis, particularly as multiple sub-units distributed along the exciter axis with respect to a mirror plane extending in an axial direction perpendicular to the axis of rotation, in order to obtain, for example, the same bearing force and a symmetrical amplitude in the direction of the axis of rotation. Importantly, these sub-units of an unbalanced mass are either fixed in position relative to the exciter axis as a whole, or are collectively moved from one end position to another by the same action pulse during displacement. Attached Figure Description

[0034] The present invention will now be described in more detail with reference to the embodiments shown in the accompanying drawings. The drawings schematically illustrate:

[0035] Figure 1 A side view of a ground compaction device of the type of twin-drum roller is shown.

[0036] Figure 2 A side view of a single-drum type ground compaction equipment is shown.

[0037] Figure 3 A diagram of a vibration exciter with a power transmission system is shown;

[0038] Figure 4A A plan view of the component that forms the third unbalanced mass is shown;

[0039] Figure 4B A plan view of the component that forms the first unbalanced mass is shown;

[0040] Figure 4C A plan view of the component that forms the second unbalanced mass is shown;

[0041] Figure 5A and Figure 5B A diagram showing the positions of the first unbalanced mass relative to the third unbalanced mass at both ends;

[0042] Figure 6 The diagram shows a third unbalanced mass that has been inserted. Figure 5A The layout structure within;

[0043] Figure 7A and Figure 7B A diagram illustrating how the adjustability of the second unbalanced mass relative to the third unbalanced mass works;

[0044] Figures 8A to 8D A diagram showing four different relative positions of the first, second, and third unbalanced masses is presented, where the total eccentricity gradually decreases at the initial position;

[0045] Figures 9A to 9D Showing with Figures 9A to 9D A diagram showing the magnitude of the relative positions of the components at a given rotational speed.

[0046] Figure 10 A perspective view showing an alternative embodiment of the vibration exciter; and

[0047] Figure 11 A flowchart illustrating the method is shown. Detailed Implementation

[0048] In each drawing, the same or identical components use the same reference numerals. Components that appear repeatedly are not numbered separately in each drawing.

[0049] Figures 1 to 2A side view shows different ground compaction devices 1, each equipped with one or more vibration exciters 2 (indicated by dashed lines). Each ground compaction device includes a ground contact device 3, through which the device directly contacts the ground surface U to be compacted and transmits vibrations generated by the one or more vibration exciters 2 to the ground surface. One ground contact device 3 may be coupled with one or more vibration exciters 2. For planar ground compaction, the ground compaction device 1 can be moved on the ground surface in a forward and / or backward direction by its own drive mechanism or at least partially by human power.

[0050] Figure 1 This is a self-propelled, twin-drum roller type ground compaction device 1, wherein the ground contact device 3 is constructed as a front roller drum and a rear roller drum, and at least one vibration exciter 2 is installed in its internal space. The ground compaction device includes a frame 4, on which a cab 5 is mounted. The driving energy required for travel and operation is generated by a drive motor 6. The ground compaction device 2 can be connected to the front roller drum and the rear roller drum via a turntable hinge device. A bent-hinged construction of this type of ground compaction device is also feasible. This ground compaction device can be used, for example, in road construction to compact asphalt pavements.

[0051] Figure 2 The ground compaction equipment 1 shown is a single-drum roller, with its ground contact device 3 being the front roller drum, and at least one vibration exciter 2 housed within its internal space. The single-drum roller may have a bent-hinged frame 4, with its front and rear frame halves connected via a bent-hinged joint. The drive wheels may be mounted on a trailer. This ground compaction equipment can also be self-propelled.

[0052] This ground compaction equipment 1 can be manually driven and / or remotely controlled by an operator traveling with the ground compaction equipment 1.

[0053] Figure 3Further details of a feasible configuration for a vibration actuator 2 and its connection to a power transmission system are illustrated exemplary. A drive motor 6 (e.g., an electric motor or a hydraulic motor) is driven to the vibration actuator 2 via a power transmission system 8 (here, for example, a drive unit), wherein a direct drive unit is also feasible. The power transmission system 8 is connected to the actuator shaft 9 on its output side, the actuator shaft being supported within a housing 10 in a manner rotatable about a rotation axis R. The power transmission system 8 and / or the drive motor 6 are configured such that the actuator shaft 9 can be selectively rotated clockwise or counterclockwise. This can be achieved directly by switching the drive direction of the drive motor 6, or via a switching transmission mechanism located in the power transmission system. Optional third unbalanced mass U3, first unbalanced mass U1, and second unbalanced mass U2 are supported on the actuator shaft 9 such that these three unbalanced masses U1, U2, and U3 are driven by the rotating actuator shaft 9 and are placed in rotation. Therefore, during the vibration 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 can be understood that the corresponding unbalanced masses U1, U2, and U3 can be formed by a single component or by multiple components respectively. Thus, the unbalanced masses U1, U2, and U3 each represent an interacting unit with a function that will be described in more detail below. The unbalanced mass U3 can be constructed as a single piece and even as a single piece with the exciter shaft 9. The unbalanced mass U1 is a so-called reversing counterweight, and its relative position to the unbalanced mass U3 can be adjusted between two end positions according to the direction of rotation of the exciter shaft 9 about the rotation axis R. In contrast, the unbalanced mass U2, independent of the direction of rotation of the exciter shaft 9, lies between a first end position (shown as a solid line in Figure 4) and a second end position (shown as a dashed line U2' in Figure 4), which differ in their eccentricity, i.e., in the distance between their respective centers of mass and the rotation axis R, as will be described in more detail below.

[0054] The ground compaction equipment may have a control unit 11 configured to set and / or control the adjustment possibilities described below to provide different vibration amplitudes. A sensor device 12 may also be provided for detecting one or more parameters related to setting and / or controlling these adjustment possibilities. For this purpose, the sensor device 12 may include, for example, a rotation angle sensor 13, a rotation direction sensor 14, a rotation speed sensor 15, and a position sensor 16 for determining the relative positions of a first unbalanced mass U1 and / or a second unbalanced mass U2 with respect to a third unbalanced mass U3 and / or the actuator shaft 9. The control unit 11 may be signal-connected to the sensor device 12. Furthermore, a display device 17 (e.g., a monitor) and / or a selection device 18 (e.g., an input keyboard) may be provided and signal-connected to the control unit 11, via which the current operating mode can be displayed and / or selected.

[0055] Figure 4A , Figure 4B and Figure 4C First, the third unbalanced mass U3 with exciter shaft 9 is shown in a top view. Figure 4A ), first unbalanced mass U1 ( Figure 4B ) and the second unbalanced mass U2 ( Figure 4C An exemplary structural configuration of ).

[0056] according to Figure 4A The third unbalanced mass U3 may have a mass unit constructed essentially in the form of a semi-shell 19, which extends semi-circularly around the axis of rotation R and at a certain radial distance therefrom. A receiving container 20 and a rotation stop 21, which is a rotation restriction relative to the first unbalanced mass U1, as described in more detail below, may also be provided. The unbalanced mass U3 has a center of mass M3, which is radially spaced from the axis of rotation R by a distance EX3. This distance EX3 represents the eccentricity of the unbalanced mass U3. The actuator shaft 9 may be constructed as a single piece with the unbalanced mass U3. It has radially guided portions in certain areas; for this purpose, the actuator shaft 9 has two linearly opposite and parallel-extending abutment surfaces 26, and for this purpose, for example, has an elongated outer contour, or the two abutment surfaces 26 are connected to each other via a rounded bridging region. In this region (as shown in the figure below, the second unbalanced mass U2 is guided in this region), the actuator shaft 9 is perpendicular to the axis of rotation 09 in cross-section and is therefore constructed to be non-circular.

[0057] Figure 4B The first unbalanced mass U1 is shown in a top view. The first unbalanced mass may be constructed, for example, as a circular segment and include the actuator shaft through-hole 22 as part of a rotary bearing. The center of mass of the first unbalanced mass U1 is marked M1. The first unbalanced mass U1 may also include two opposing stop sidewalls 23, 23', which may be constructed to abut against the rotary stop portion 21 of the third unbalanced mass U3.

[0058] according to Figure 4C The second unbalanced mass has a center of mass M2. Currently, the linear guide structure 27 is obtained by longitudinally elongated sidewalls 25 of an elongated aperture 24 that extend parallel to each other and are opposite to each other, the elongated aperture generally having an elongated profile in the illustrated plane. The center of mass M2 is located within the elongated aperture 24.

[0059] The current diagram shows the centroids M1, M2, and M3 respectively in the projection onto the observation plane, or in a virtual reference plane perpendicular to the axis of rotation.

[0060] Figure 5A and5B First, the relationship between the relative position of the third unbalanced mass U3 and the first unbalanced mass U1 and the rotation direction of the actuator shaft is shown. The current rotation direction of the actuator shaft 9 is given by R1 and R2. The first unbalanced mass U1 is disposed on the actuator shaft 9, for which the actuator shaft 9 is guided through the actuator shaft through-hole 22. When the actuator shaft 9 rotates counterclockwise along the R1 direction, the first unbalanced mass U1 abuts against the rotation stop 21 with side 23; while when the actuator shaft 9 rotates clockwise along the R2 direction, it abuts against the rotation stop with side 23'. Therefore, the unbalanced mass U1 abuts against different sides according to the rotation direction R1 / R2 and is subsequently driven by the actuator shaft 9 in the corresponding rotation direction as the rotational movement continues. The adjustment movement of the first unbalanced mass U1 relative to the third unbalanced mass U3 and the actuator shaft (9) is here opposite to the corresponding rotation direction of the actuator shaft 9 and runs around the reversing axis UA, which in this embodiment extends coaxially with the rotation axis R. Since the centers of mass of the third unbalanced mass U3 and the first unbalanced mass U1 can thus obtain two different relative positions, the overall centers of mass of these two unbalanced masses U3 and U1 can change in terms of their radial distance from the axis of rotation R, thereby generating two different vibration amplitudes depending on the direction of rotation at a given rotational speed.

[0061] Figure 6 In the middle, supplemented Figure 5A and Figure 5BThe arrangement structure incorporates a second unbalanced mass U2. This second unbalanced mass is also located on the actuator shaft 9, but is held in place to prevent rotation. The actuator shaft 9, constructed as a non-circular cross-section perpendicular to the rotation axis R, passes through the elongated hole 24 in the through-area and is fitted against the longitudinal sidewall 25 of the second unbalanced mass U2 with opposing contact surfaces 25, thereby forming a linear guide structure 27. This linear guide structure enables the displacement of the second unbalanced mass U2 in the radial direction. Therefore, unlike the first unbalanced mass U1, the second unbalanced mass U2 is forcibly guided in an anti-rotation manner along each rotational movement of the actuator shaft 9 in both rotational directions, especially even when the current rotational direction of the actuator shaft 9 is reversed. Thus, the longitudinal guide portion 27 here simultaneously forms an anti-rotation structure 35 for the second unbalanced mass U2 relative to both the third unbalanced mass U3 and the actuator shaft 9. Simultaneously, the second unbalanced mass U2 can be displaced along the linear guide structure 27 formed by the elongated hole 24, and thus is displaced radially relative to the rotation axis R. This can be achieved using a dedicated drive element for displacement, or it can be achieved by gravity. For this purpose, the actuator shaft 9 is positioned and held in a rotational position, in which the axis of motion of the second unbalanced mass U2 preferably extends vertically. The degree of this displacement is limited radially by a stop formed between the elongated hole 24 and the actuator shaft 9. Similar to the first unbalanced mass U1, the relative position of the second unbalanced mass U2 with respect to the third unbalanced mass U3 and the actuator shaft 9 can therefore be adjusted, but in a different direction, i.e., particularly radially with respect to the axis of rotation R. Figure 6 (Represented by arrow C).

[0062] Figure 7A and Figure 7B The following position is shown, in which the second unbalanced mass U2 is driven by gravity to slide into one of its two end positions. Figure 7A The first end position is shown. Figure 7B The second end position is shown. Here, the second unbalanced mass U2 slides to the corresponding stop position along the linear guide structure between the actuator shaft 9 and the elongated hole 24 due to its own weight. The second unbalanced mass U2 can be constructed in particular such that the second center of mass M2 not only changes its radial distance relative to the axis of rotation R between these two end positions, but also passes through a virtual plane in which the axis of rotation R extends and which is oriented transversely to, and in particular perpendicularly to, the direction of displacement of the second unbalanced mass M2 relative to the actuator shaft 9. This virtual plane... Figure 7A and Figure 7BThe symbol is H. Therefore, not only is the radial distance of the center of mass M2 of the second unbalanced mass U2 relative to the axis of rotation R different in the two end positions, but the position of the second center of mass M2 relative to the actuator shaft 9 is also on different sides, meaning the second center of mass is located on opposite sides of the plane. This is advantageous in this respect because the centrifugal force acting on the second unbalanced mass U2 in the two end positions during the rotational operation of the actuator shaft 9 acts towards the stops respectively present between the actuator shaft 9 and the second unbalanced mass U2, stabilizing it in its current relative position. This eliminates the need for an additional locking device that holds the second unbalanced mass in one or both end positions, and which is inherently feasible and also included in this invention.

[0063] Figure 7A and Figure 7B It is also explained that the radial distance of the total centroid MS changes simply by occupying the two end positions of the second unbalanced mass U2. Regarding this, in Figure 7A and Figure 7B The positions of the centers of mass M1, M2, and M3 of the three unbalanced masses U1, U2, and U3 are given. The total center of mass MS of the three unbalanced masses is derived from the relative positions of the three elements with respect to the axis of rotation R. Figure 7B In the arrangement of the three unbalanced masses U1, U2, and U3, the unbalance effect of the second unbalanced mass U2 is superimposed on the unbalance effects of the first and third unbalanced masses U1 and U3, while according to... Figure 7A In the arrangement, the imbalance effect of the second unbalanced mass U2 acts subtractively from the imbalance effects of the unbalanced masses U1 and U3 because its center of mass M1 is located on the opposite side of the plane H from the other two centers of mass M2 and M3. Accordingly, the total eccentricity EXS, or the vibration amplitude generated at the limited rotational speed of the excitation shaft 9, can be changed solely by shifting the relative positions of the second unbalanced mass U2 with respect to the first and second unbalanced masses U1 and U3, and the total eccentricity specifically... Figure 7A Middle and small Figure 7B middle.

[0064] Figure 7A and Figure 7B The diagram further illustrates a feasible scheme for constructing the unbalanced masses U1 to U3 and the guides for changing their relative positions, such that their centers of mass M1, M2 and M3 lie on a common straight line G at their respective end positions.

[0065] In summary, the arrangement structure described above can thus realize four different relative arrangement structures of the three unbalanced masses U1, U2, and U3, which in Figures 8A to 8D The data shows that the total eccentricity decreases. Figures 9A to 9D This is illustrated using time-displacement diagrams to show the vibrations, or vibration amplitudes, A1 to A4, generated at a common defined rotational frequency or speed of the exciter shaft. Figure 8A correspond Figure 9A , Figure 8B correspond Figure 9B , Figure 8C correspond Figure 9C ,and Figure 8D correspond Figure 9D In practical use, the operator can therefore select between amplitudes A1 to A4 generated by the vibration exciter 2 by adjusting the relative positions of the unbalanced masses U1, U2, and U3 as a whole, with the arrangement shown. Additionally, it can be specified that the rotational speed of the exciter shaft 9 is also variable during vibration operation to further alter the generated amplitude spectrum.

[0066] Figure 10 Another alternative embodiment of the vibration exciter 2 is shown in a perspective oblique view. In this alternative embodiment, the linear guide structure 27 for the second unbalanced mass U2 is implemented, for example, by means of two guide shafts 28 extending through the exciter shaft 9, which are guided through two through holes 29 passing through the exciter shaft 9. The first and second end positions are predefined by a guide frame 30 surrounding the exciter shaft 9.

[0067] Figure 11 A flowchart is shown for a method of adjusting the vibration amplitude of a vibration exciter 2 for a ground compaction device 1. In the method, a first step 31 specifies that the exciter shaft and a third unbalanced mass (if present) connected to the exciter shaft in a rotationally resistant manner are rotated to one of two defined adjustment rotation positions, preferably offset from each other by 180°, or at least within one of the adjustment rotation regions. Then, in step 32, based on the adjustment rotation position to which the exciter shaft has been adjusted, a second unbalanced mass (particularly gravity-driven) is adjusted to one of two defined end positions relative to the exciter shaft 9. Subsequently, in step 33, the rotation direction of the exciter shaft is specified, and the exciter shaft is accelerated into rotational motion about the rotation axis of the exciter shaft in the direction of the specified rotation direction. Following step 33, finally in step 34, based on the current rotation direction of the exciter shaft, the defined relative position of the first unbalanced mass relative to the third unbalanced mass is adjusted from two defined possible relative positions.

[0068] It can be stipulated that steps 31 to 34 are controlled and executed automatically by the control unit. To this end, it can also be stipulated that the operator first selects one of at least three (especially at least four and particularly exactly four) operating modes via an input device, or selects one of four presentable vibration amplitudes, and the control unit executes steps 31 to 34 accordingly.

[0069] The method, such as Figure 11 As shown, it is particularly suitable for implementation with one of the vibration exciters 2 shown in the remaining figures.

Claims

1. A vibration exciter for ground compaction equipment, the vibration exciter comprising: - A actuator shaft (9) that can rotate about the rotation axis (R). - A first unbalanced mass (U1) is eccentrically positioned relative to the rotation axis (R) of the actuator shaft (9). The first unbalanced mass is supported on the actuator shaft (9) such that it can rotate relative to the actuator shaft (9) within the commutation range about a commutation axis (UA) that extends coaxially or parallel to the rotation axis (R) of the actuator shaft (9) and can occupy two different end positions relative to the actuator shaft (9) depending on the rotation direction (R1, R2) of the actuator shaft (9). Its features are, A second unbalanced mass (U2) exists, which is supported on the actuator shaft (9) and can be placed by the actuator shaft in rotation about a rotation axis (R). The second unbalanced mass can be moved between a first end position and a second end position relative to the rotation axis (R) of the actuator shaft (9) and relative to the first unbalanced mass (U1), independent of the rotation direction (R1, R2) of the actuator shaft (9). The second unbalanced mass (U2) has a center of mass (M2), which, in the first end position, is radially oriented relative to the actuator compared to the second end position. The distance of the rotation axis (R) of the shaft (9) is greater. When the second unbalanced mass (U2) is moved from the first end position to the second end position, the center of mass (M2) of the second unbalanced mass (U2) passes through the virtual plane (H) in which the rotation axis (R) of the actuator shaft (9) is located and the virtual plane extends perpendicular to the direction of the second unbalanced mass (U2) between the first end position and the second end position. The second unbalanced mass (U2) is supported on the actuator shaft (9) such that the movement of the second unbalanced mass (U2) from the first end position to the second end position is driven by gravity.

2. The vibration exciter for ground compaction equipment according to claim 1, Its features are, There is a third unbalanced mass (U3), which is eccentrically positioned relative to the rotation axis (R) of the actuator shaft (9), and the position of the third unbalanced mass relative to the actuator shaft (9) is fixed.

3. The vibration exciter for ground compaction equipment according to claim 1, Its features are, The second unbalanced mass (U2) is supported on the actuator shaft (9) via a linear guide structure (27), wherein the linear guide structure (27) is configured such that the displacement of the second unbalanced mass (U2) between a first end position and a second end position is carried out along a linearly extending displacement axis. and / or There is a third unbalanced mass (U3) that is eccentrically positioned relative to the axis of rotation (R) of the actuator shaft (9) and is fixed in position relative to the actuator shaft (9). The second unbalanced mass (U2) is supported on the third unbalanced mass (U3) via a linear guide structure (27), wherein the linear guide structure (27) is configured such that the displacement of the second unbalanced mass (U2) between a first end position and a second end position is carried out along a linearly extending displacement axis.

4. The vibration exciter for ground compaction equipment according to claim 3, Its features are, The linear guiding structure (27) has at least one of the following characteristics: - The linear guide structure defines a displacement axis that extends radially relative to the axis of rotation (R); - The linear guide structure includes at least one linear through hole (29) in the actuator shaft (9) and a guide shaft (28) fixedly connected to the position of the second unbalanced mass (U2), the guide shaft extending through the linear through hole (29); - The linear guide structure includes two guide sidewalls (25) which are fixedly connected to the position of the second unbalanced mass (U2), extend opposite to each other and parallel to each other, and guide on the outer surface of the actuator shaft (9).

5. The vibration exciter for ground compaction equipment according to any one of claims 1 to 4, Its features are, An anti-rotation structure (35) is provided, which is configured such that the second unbalanced mass (U2) cannot rotate relative to the axis of rotation (R) of the actuator shaft (9).

6. The vibration exciter for ground compaction equipment according to any one of claims 2 to 4, Its features are, The first end position and / or the second end position of the second unbalanced mass (U2) relative to the third unbalanced mass (U3) are determined by a mechanical stop (21).

7. The vibration exciter for ground compaction equipment according to claim 6, Its features are, The stop (21) of the machine is a stop (21) formed by the actuator shaft (9) itself.

8. The vibration exciter for ground compaction equipment according to any one of claims 2 to 4, Its features are, The vibration exciter is configured such that the third unbalanced mass (U3) and the first unbalanced mass (U1) each have a center of mass, and the first unbalanced mass, the second unbalanced mass, and the third unbalanced mass can be displaced 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 of the first unbalanced mass, the second unbalanced mass, and the third unbalanced mass lie on a common straight line extending radially relative to the axis of rotation (R).

9. The vibration exciter for ground compaction equipment according to any one of claims 2 to 4, Its features are, The second unbalanced mass (U2) is supported on the actuator shaft (9) such that the displacement of the second unbalanced mass (U2) relative to the third unbalanced mass (U3) from the first end position to the second end position is driven solely by gravity.

10. The vibration exciter for ground compaction equipment according to any one of claims 1 to 4, Its features are, There is a means for detecting at least the occupation of the actuator shaft (9) in two different adjustment rotation positions.

11. The vibration exciter for ground compaction equipment according to any one of claims 2 to 4, Its features are, There are means for selectively adjusting and maintaining at least a first and a second adjustment rotational position of the actuator shaft (9), wherein in the first adjustment rotational position, the second unbalanced mass (U2) is moved to a first end position, and in the second adjustment rotational position, the second unbalanced mass (U2) is moved to a second end position relative to the third unbalanced mass (U3).

12. The vibration exciter for ground compaction equipment according to any one of claims 1 to 4, Its features are, There exists a control unit (11) configured such that, when a pre-given operating mode is selected from at least three different feasible operating modes relating to the total eccentricity EXS of the vibration exciter (2), the control unit at least - Pre-defined adjustment rotational position of actuator shaft (9) and / or rotational direction of actuator shaft (9) and / or - Control the actuator shaft (9) to occupy a predetermined adjustment rotation position in time and then control the acceleration of the actuator shaft (9) in a predetermined rotation direction.

13. The vibration exciter for ground compaction equipment according to any one of claims 1 to 4, Its features are, A sensor device (12) is present, the sensor device being configured to detect at least: the occupation of one of the two different end positions by a first unbalanced mass (U1) and / or the occupation of the first end position and / or the second end position by a second unbalanced mass.

14. A ground compaction device with a vibration exciter, said vibration exciter being a vibration exciter according to any one of claims 1 to 13. Its features are, The ground compaction equipment is a road roller.

15. The ground compaction equipment with a vibration exciter according to claim 14, Its features are, The ground compaction equipment is a double-drum roller or a single-drum roller.

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