Soil compacting device with adaptive exciter

Abstract

A soil compaction device for compacting soil is specified, comprising a vibration exciter device (14) for generating a vibration for soil compaction, in which at least two parameters that influence the vibration generated by the vibration exciter device (14) are variable; a soil compaction measuring device (18) for detecting a compaction state of the soil; and a control device (1, 17) for adjusting at least one of the at least two parameters; wherein the control device (1, 17) is designed to automatically adjust at least one of the at least two variable parameters depending on the detected compaction state and a predetermined set of rules.

Description

[0001] The invention relates to a soil compaction device with adaptive unbalance exciter.

[0002] Vibrating plates and vibrating rammers are particularly suitable as soil compaction devices.

[0003] Vibratory plates are often powered by an internal combustion engine, particularly a diesel engine, which is controlled by a simple control unit. Vibratory plates often feature a device for detecting soil compaction, such as the Compatec System® from Wacker Neuson, which serves as a compaction control system. The engine speed is usually adjusted between just two speeds: idle and full throttle. If the corresponding control device determines that the soil has already been sufficiently or even excessively compacted, the control unit sets the engine to idle to prevent the machine from jumping and thus causing damage.

[0004] Such an overload shutdown in the case of over-compacted soils and a resulting reduction in engine speed is a simple form of operator support.

[0005] Operating a soil compaction device ideally requires a thorough understanding of the soil conditions and the machine's capabilities. Overcompaction, in particular, must be avoided, as this is uneconomical and can lead to damage to the soil compaction device if the machine jumps. On the other hand, it must also be ensured that the soil to be compacted is sufficiently compacted across its entire surface to meet the compaction requirements. Insufficiently compacted soils can subsequently lead to accidents and liability risks.

[0006] However, soil compaction equipment is often operated by operators with little knowledge or training. While these operators are able to recognize sufficient soil compaction, it has been shown that this leads to a tendency toward overcompaction, with the adverse consequences mentioned above.

[0007] Vibration plates typically have imbalance exciters in which one or more imbalance shafts are driven in rotation. The imbalances of the exciters can be radially fixed to the imbalance shaft that supports them, manually adjustable, or spring-loaded and adjustable. On switchable vibration plates, i.e. vibration plates whose direction of travel can be changed (forward, reverse), the adjustment of the resulting centrifugal force vector is manually specified by the operator. By changing the centrifugal force vector unilaterally with respect to the direction of travel (left, right), rotational movements around the vertical axis and thus steering movements of the vibration plate can be performed. The speed of the imbalance exciter is also manually specified by the operator, particularly with the help of a throttle lever or a speed preselection in the case of an electric drive.

[0008] In known vibrating plates and rammers, the unbalance exciters or excitation systems equipped in the manner described do not respond optimally, and in particular, do not respond to different soil conditions. Rather, the operating states of the unbalance exciters, in particular the unbalance and centrifugal force effects generated by them, are maintained regardless of the respective soil conditions. The operating states depend solely on the operator's specifications or settings.

[0009] For example, if the soil is already fully compacted, the preset centrifugal force may be too high. Consequently, the travel speed is low, causing the compactor to move too slowly for the existing conditions and thus remain on the soil that cannot be further compacted for an unnecessarily long time.

[0010] In another example, the machine passes over unevenly compacted soil with unchanged frequency, centrifugal force, and forward speed (travel speed). This results in the soil remaining unevenly compacted even after this pass. The remaining, insufficiently compacted areas usually have to be passed over several times until the soil is completely compacted.

[0011] In yet another example, it can be observed that on a steep slope or with a high fill height, the compactor, with the standard centrifugal force and force vector settings, only moves slowly or even gets stuck. The operator may then have to move the machine further using their own power.

[0012] These examples demonstrate that if the soil compaction device, especially its vibration exciter, is not adjusted appropriately to the specific situation (especially the soil compaction level), a significant amount of working time can be wasted. This makes effective, efficient work more difficult.

[0013] The invention is based on the object of providing a soil compaction device which enables an operator to work more effectively without placing special demands on him.

[0014] The object is achieved according to the invention by a soil compaction device having the features of claim 1. Advantageous embodiments are specified in the dependent claims.

[0015] A soil compaction device for compacting soil is specified, comprising a vibration exciter device for generating a vibration for soil compaction, in which at least two parameters that influence a vibration generated by the vibration exciter device are variable. A soil compaction measuring device serves to detect a compaction state of the soil, wherein a control device is further provided for adjusting at least one of the at least two parameters, and wherein the control device is designed to automatically adjust at least one of the at least two variable parameters depending on the detected compaction state and a predetermined set of rules.

[0016] The set of rules can be stored in the control unit, for example. However, it can also be stored elsewhere, such as an external computer that communicates with the soil compaction device. The set of rules can be stored in the form of characteristic curves, tables, characteristic maps, etc.

[0017] The parameters are suitable for influencing the vibration generated by the vibration excitation device. The parameters can be automatically changed individually or in combination. For example, more than two parameters can be changed, such as three or more.

[0018] Setting the parameters means in particular that the parameters can be changed within certain limits and in accordance with the specified rules depending on the respective recorded compaction state of the soil in order to optimise the operation of the soil compaction device depending on the recorded compaction state of the soil.

[0019] For example, the soil compaction device can detect the compaction state of the subsoil using sensors, which then optimizes the vibration force and forward speed. For example, an acceleration sensor can be provided that, in a typical soil compaction device, measures the movement of a lower mass and / or an upper mass, which can be evaluated as a criterion for the respective compaction state of the soil. Based on the movement behavior of the upper mass and / or the lower mass in comparison with stored characteristic curves / maps, the compaction parameters of the vibration exciter device are adjusted such that the compaction performance and movement progress are optimal for the current subsoil.

[0020] Accordingly, a vibration exciter can be controlled via a compaction detection system with an evaluation and control unit, allowing automated adjustment of the centrifugal force, excitation frequency, or unbalance adjustment angle, or a combination of these parameters. Furthermore, components of the upper mass can be adjusted in terms of their position and / or buffer stiffness between the upper and lower masses.

[0021] The solution according to the invention thus enables the provision of an adaptive vibration exciter device or an adaptive unbalance exciter in which the compaction parameters are adapted to the respective compaction state of the soil.

[0022] The soil compaction device can have a vibration adjustment device for changing at least one of the at least two parameters. The vibration adjustment device can be suitably designed to effect the change in the respective parameter with the aid of electrical and / or mechanical measures. This can be achieved using various measures, such as, for example, by displacing an unbalanced mass relative to the unbalanced shaft supporting it, displacing a center of gravity, or displacing components of the soil compaction device relative to one another. Likewise, the drive power of a drive of the soil compaction device or its speed can be changed.

[0023] The vibration exciter device can comprise at least one unbalance exciter with at least one unbalance shaft supporting an unbalance mass. The unbalance shaft can be a shaft on which an unbalance mass is arranged, rotating with the shaft, to generate a rotating centrifugal force (centrifugal force) and thus an unbalance effect. The design of such an unbalance exciter is widely known and therefore need not be explained further here.

[0024] The adjustable parameters can be selected from the group explained below: One parameter can be the centrifugal force of the imbalance exciter. A change in the centrifugal force directly causes a change in the compaction effect of the soil compaction device. The change in the centrifugal force can be brought about by a single imbalance mass or a combination of several, e.g., two, imbalance masses. Accordingly, the change in the centrifugal force can also be brought about by a combination of several, e.g., two, imbalance shafts.

[0025] Another variable parameter is the radial position of the unbalanced mass relative to the rotational axis of the unbalanced shaft. This position can be achieved, for example, by radially shifting the unbalanced mass between an inner and an outer radial extreme position. For example, if the soil is already sufficiently compacted, the centrifugal force should be reduced, so it may be advisable to shift the respective unbalanced mass radially inward, toward the rotational axis of the unbalanced shaft, to reduce the centrifugal force effect.

[0026] Another parameter can be the activation or deactivation of an imbalance mass. The imbalance mass or the imbalance shaft supporting it can be activated or deactivated in a similar way to a transmission synchronizer. This can also cause a change in centrifugal force.

[0027] Another parameter can be to provide for different adjustments of the unbalance masses on the unbalance shafts when using multiple unbalance shafts. For example, a targeted "detuning" of the soil compaction device can be achieved by radially shifting the unbalance shafts between the inner and outer extreme radial positions, but with different adjustments for different unbalance shafts. For example, with unbalance exciters with two unbalance shafts, a desired movement behavior can be achieved.

[0028] This can also be achieved by switching unbalance masses on and off, but differently on a front and a rear unbalance shaft, in order to detune the unbalance exciter and thus set a desired movement behavior.

[0029] Complete unbalance shafts can also be switched on or off, whereby an asymmetrical switching is carried out with regard to the soil compaction device in order to detune the exciter.

[0030] Another parameter can be the position of the imbalance exciter on a ground contact element that acts on the soil to be compacted. By changing the position of the imbalance exciter, the acting centrifugal force can also be changed.

[0031] Another variable parameter is the excitation frequency. This can, in particular, be the rotational speed of one or more unbalanced shafts. For example, a high excitation frequency can be used for sandy soils, while a lower excitation frequency is more suitable for cohesive soils.

[0032] Another parameter is the unbalance adjustment angle or the phase position of, for example, two unbalance shafts. In particular, the two unbalance shafts can be arranged parallel to each other in the direction of travel and coupled so that they rotate in opposite directions. The interaction of the counter-rotating unbalance masses creates a resultant force vector that can be directed in a specific direction - e.g. forwards (in the direction of travel), vertically, backwards, or horizontally. By changing the position of the counter-rotating unbalance shafts and thus their phase position, the direction of the resultant force vector can be changed. This allows a steeper or flatter force vector to be generated.For example, if the soil is still capable of being compacted, a steeper position may be useful in order to exert a strong compaction effect on the soil, whereas if the soil is already sufficiently compacted, a flatter position of the force vector may be useful in order to achieve a lower compaction effect but a greater feed effect.

[0033] Another parameter can be the relative position of the soil compaction device's components. Changing the relative position of the components results in a shift in mass, which can also cause a shift in the overall center of gravity. For example, components located on the upper mass, such as an electric battery, can be moved forward or backward to change the forward travel (travel speed) or gradeability.

[0034] Another parameter can be the stiffness of a vibration decoupling device acting between components of the soil compaction device. Soil compaction devices typically have a largely stationary upper mass and a highly mobile lower mass that performs the actual compaction work. A vibration decoupling device, such as a buffer device, is typically provided to decouple vibrations between these two components. By varying the stiffness of this vibration decoupling device or the buffers, the movement behavior of the soil compaction device can be modified.

[0035] At least some of the above-mentioned parameters, but at least two of the above-mentioned parameters, can be modified by the control device in order to change the vibration behavior of the vibration exciter device and thus the compaction behavior of the soil compaction device. The control device receives information about the current compaction state of the soil and can then derive adjustment measures from the available control system and implement the corresponding parameter changes automatically.

[0036] The soil compaction device can be a vibrating plate with an upper mass, a lower mass coupled to the upper mass via the aforementioned vibration decoupling device, and a ground contact element belonging to the lower mass, with the vibration exciter device being formed on the lower mass. In this typical design of a vibrating plate, the ground contact element can be a ground contact plate. The vibration exciter device can have one, two, or more unbalanced shafts. The vibration exciter device in a vibrating plate thus generally generates a force-excited vibration.

[0037] As an alternative to the vibrating plate, the soil compaction device can be a rammer for soil compaction, wherein the rammer has a drive which has the vibration exciter device, wherein the vibration exciter device is designed to generate a translational oscillation movement which can be transmitted to a ground contact element, wherein a spring device is provided for transmitting the translational oscillation movement to the ground contact element. The ground contact element can be, for example, a tamping foot with which the soil is compacted. The oscillation movement is a linear back and forth movement. The oscillation movement is transmitted to the tamping foot via the spring device in a known manner. This transforms the rather uniform oscillation movement into the desired tamping movement. The vibration exciter device in a rammer therefore generally generates a vibration which is excited away.

[0038] Parameters can also be adjusted on the rammer, with the changeable parameters being selected from the following group.

[0039] One parameter can be the amplitude of the oscillation movement. With the help of suitable measures, for example, in an electric drive, the amplitude of the oscillation movement can be increased or decreased, which can also lead to the pitching movement becoming smaller (weaker) or stronger.

[0040] Another parameter can be the frequency of the oscillation movement. This can be adjusted, for example, by changing the rammer's drive speed.

[0041] Another parameter can be the transmission effect of the spring system. In particular, changing the spring stiffness or the spring stroke height can cause a change, which in turn changes the pitching behavior.

[0042] The soil compaction measuring device can be designed to detect the compaction state of the soil based on the movement behavior of components of the soil compaction device. Such a measuring device is known from the prior art. For example, reference is made to the Compatec System® from Wacker Neuson, which serves as a compaction control system. There are also other soil stiffness measuring systems that can be used to detect soil properties.

[0043] Some of these measuring devices measure the acceleration of one or more components of the soil compaction device, which allows conclusions to be drawn about the compaction state of the soil. For example, an acceleration sensor can be provided on the lower mass and / or the upper mass. In a vibrating plate, the movement behavior of the lower mass and / or the upper mass, or even their mutual movement behavior, can serve as a criterion for the compaction state of the soil. The soil compaction state can be determined, in particular, based on the movement behavior in comparison with stored or saved characteristic curves / maps. A similar device is possible for a vibratory rammer.

[0044] With the help of the soil compaction device described, it is possible to compact the area more evenly after the first complete pass over soil that is too compacted than is the case with conventional, non-adaptive compaction devices. The number of passes and thus the overall compaction time can be reduced accordingly.

[0045] The soil compaction device according to the invention can be used in particular in conjunction with an autonomously operating vibrating plate. Since, with autonomous control, all parameters are adjusted without being influenced by an operator or the compaction process, optimal compaction can be achieved by evaluating the target and actual condition of the soil across the entire area to be compacted. However, the soil compaction device according to the invention can also be used with a conventional remote-controlled vibrating plate or a vibrating plate manually guided with a drawbar.

[0046] These and other advantages and features are explained in more detail below using examples and the accompanying figures. They show: Fig. 1 the schematic structure of the control of a soil compaction device according to the invention; Fig. 2a vibrating plate in schematic side view as an example of a soil compaction device according to the invention; and Fig. 3 the vibration plate from Fig. 2 in schematic top view.

[0047] Fig. 1 shows in a simplified schematic representation the control of components serving as a control device in a soil compaction device according to the invention.

[0048] At the center is a control unit 1, to which various information is fed, in particular from a pre-selection device 2, via which an operator can transmit instructions to the soil compaction device. For example, the operator can adjust the drive speed via an accelerator lever or the direction of travel via a drive lever. The operator can also specify steering commands. The pre-selection device 2 thus represents a multitude of known control elements with which an operator can control and operate a soil compaction device.

[0049] Furthermore, the control unit 1 receives information from various sensors 3. Among the sensors, there may be at least one acceleration sensor, which serves to detect the movement of the component it monitors. The sensor 3 and the measurement software stored in the control unit 1 may be part of a soil compaction measuring device (not shown), which can be used to detect the compaction state of the soil.

[0050] The control unit 1 can control various components of the soil compaction device, e.g. an actuator 4, a motor 5 serving as a drive motor, a center of gravity changing device 6 and a vibration decoupling device 7, which can have, e.g. buffers, such as rubber buffers.

[0051] The control unit 1 is designed to draw conclusions about how the components of the soil compaction device should be controlled to achieve optimal compaction based on the specifications and actual states detected by the preselection device 2 and the sensors 3. For this purpose, corresponding rules are stored in the control unit 1, e.g., in the form of characteristic curves, tables, or characteristic maps.

[0052] In particular, the control unit 1 is also designed to automatically draw conclusions from the available information and initiate appropriate measures. These measures may mean that the previously set parameters should be maintained, since essentially optimal soil compaction has been determined. However, they may also result in an automatic change to one or more of the possible parameters.

[0053] Using one or more actuators 4, mechanical changes can be made to the soil compaction device. For example, unbalanced masses or unbalanced shafts can be switched on or off to change the centrifugal force effect.

[0054] The speed of motor 5 can be changed in order to change the excitation frequency.

[0055] Using the center of gravity adjustment device 6, it is possible to shift components of the soil compaction device relative to each other, thereby changing the position of the center of gravity. By shifting the center of gravity, for example, further forward (in the direction of travel) or further back (in the direction of reversing), the compaction behavior of the soil compaction device also changes.

[0056] The vibration decoupling device 7 is intended, as will be explained later with reference to the Figures 2 and 3It is explained how to couple an upper mass and a lower mass of the soil compaction device together and simultaneously decouple them in terms of vibration. By changing the decoupling behavior, e.g., the spring stiffness, a change in the compaction behavior of the soil compaction device can also be achieved.

[0057] In the Figures 2 and 3 An example of a soil compaction device according to the invention in the form of a vibrating plate 10 is explained in a highly schematic manner. Fig. 2 shows the side view, Fig. 3 the top view.

[0058] The vibration plate 10 has a lower mass 11 and an upper mass 12 which are coupled to each other, with simultaneous vibration decoupling, as will be explained later.

[0059] The lower mass 11 has a ground contact plate 13 on which a vibration excitation device 14 is arranged. The vibration excitation device 14 has several unbalance exciters 15, which will be explained later.

[0060] An electric battery 16 is provided on the upper mass 12, in which electrical energy for driving the unbalance exciters 15 is stored.

[0061] Furthermore, a control device 17 is arranged on the upper mass 12, which receives, among other things, information from various sensors 18. The sensors 18 can be, for example, acceleration sensors, which, like the Figures 2 and 3 show, can be arranged at different locations on the vibration plate 10.

[0062] Furthermore, in the example shown, a guide bar 19 is arranged on the upper mass 12, via which an operator can manually guide the vibrating plate 10. Additionally or alternatively, a remote control 20, in particular an infrared remote control 20, is provided, via which an operator can remotely control the vibrating plate 10.

[0063] The lower mass 11 and the upper mass 12 are coupled to each other via a vibration decoupling device 13. The vibration decoupling device 13 can comprise spring and damper elements. For example, the vibration decoupling device 13 can comprise rubber buffers that connect the upper mass 12 to the lower mass 11. Furthermore, the vibration decoupling device 13 can comprise coupling elements with variable characteristics in order to change the spring or damper properties. Thus, the vibration decoupling device 13 represents a buffer system. In particular, the components of the vibration decoupling device 13 can be arranged at the four corners of the ground contact plate.

[0064] The components of the vibration decoupling device 21 are arranged in particular at the four corners of the ground contact plate 13, as Fig. 3in plan view. Further elements of the vibration decoupling device 21 can also be arranged in the middle of the ground contact plate 13, as Fig. 3 shows.

[0065] The unbalance exciters 15 can be constructed identically or differently. Fig. 3 shows examples.

[0066] In particular, each of the imbalance exciters 15 can have an electric motor 22 as its drive. Typically, the electric motor 22 drives an imbalance shaft 23 in rotation, each imbalance shaft 23 carrying one or more imbalance masses 24. The rotation of the imbalance shaft 23 with the imbalance mass 24 and several partial imbalance masses forming the imbalance mass 24 generates a centrifugal force that can be directly transferred to the ground contact plate 13 and thus to the soil to be compacted.

[0067] In the interaction of the various unbalance shafts 23 and the unbalance masses 24, resulting force vectors are also created in a known manner, which can generate the compaction on the one hand and a propulsion of the vibrating plate 10 on the other hand, depending on the direction of the resulting centrifugal force.

[0068] The unbalance mass 24 can also comprise several partial unbalance masses, as in Fig. 3 clearly visible. The partial unbalance masses can also be adjustable relative to each other and relative to the unbalance shaft 23 that supports them. In particular, their position can be changed.

[0069] On the ground contact plate 13, the various imbalance exciters 15 can be switched on or off depending on the application in order to achieve different vibration and thus compaction behavior. For this purpose, the control device 17 is suitably designed to automatically switch the imbalance exciters 15 on and off, depending on information supplied, for example, via the sensors 18.

[0070] In the Fig. 3 In the example shown, the active unbalance exciters 15 (in the example shown, four active unbalance exciters 15) are marked with a solid black line, while the currently switched off unbalance exciters 15 (in the example shown, three switched off unbalance exciters 15) are shown with a dashed line.

[0071] The dashed unbalance exciters 15 can be optionally switched on or off accordingly.

[0072] It is also possible to move the unbalance exciters 15 relative to the ground contact plate 13 supporting them with the aid of actuators (not shown), in order to change the center of gravity of the entire system and thus also the vibration and compaction behavior.

[0073] It is also possible to move components of the upper mass 12, e.g. the battery 16, relative to the other components in order to change the position of the overall center of gravity.

[0074] Furthermore, the positions of the unbalanced masses 24 can be adjusted within an unbalance exciter 15. For example, an unbalanced mass 24 can be rotated with respect to its rotational position relative to the unbalanced shaft 23 that supports it. In another example, the radial position of an unbalanced mass 24 can be changed relative to the rotational axis of the unbalanced shaft 23 that supports it. In this way, for example, the center of gravity of the unbalanced mass can be changed radially between an inner and an outer extreme position in order to change the centrifugal force effect.

[0075] It should be noted that the Figures 2 and 3 The examples shown serve only to illustrate the variety of possibilities. In practical use, in order to limit the design effort, only a portion of the modification options mentioned may be implemented, not the variety shown in the figures.

[0076] What all solutions have in common is that the control device 17 receives information from sensors 18, from which it can draw conclusions about the current compaction state of the soil on which the vibrating plate 10 is currently located. Based on this information, the control device 17 can change the various parameters with the aid of appropriate control systems and, for example, change the speed of the electric motors 22, change the radial position of the unbalanced masses 24, change the position of the overall center of gravity, switch the unbalance exciter 15 on or off, etc. This allows the vibrating plate 10 to automatically adapt to the respective soil conditions and thus to the compaction state of the soil. On still soft, uncompacted soils, the vibrating plate 10 can automatically produce a strong compaction effect, while it can be moved quickly over already compacted soils at a high feed rate but with a lower compaction effect.In this way, very effective work with the vibration plate is possible with the help of an adaptive exciter.

Claims

1. Soil compaction device for compacting soil, comprising - a vibration exciter device (14) for generating a vibration for soil compaction, in which at least two parameters that influence the vibration generated by the vibration exciter device (14) are variable; - a soil compaction measuring device (18) for detecting a compaction state of the soil; and - a control device (1, 17) for adjusting at least one of the at least two parameters; wherein - the control device (1, 17) is designed to automatically adjust at least one of the at least two variable parameters depending on the detected compaction state and a predetermined set of rules.

2. Soil compaction device according to claim 1, comprising a vibration adjustment device for changing at least one of the at least two parameters.

3. Soil compaction device according to one of the preceding claims, wherein - the vibration exciter device (14) has at least one unbalance exciter (15) with at least one unbalance shaft (23) carrying an unbalance mass (24); - the variable parameters are selected from the group + centrifugal force effect of the unbalance exciter (15) + radial position of the unbalance mass (24) in relation to a rotation axis of the unbalance shaft (23) + switching an unbalance mass (24) on or off + in the case of several unbalance shafts (23), different adjustment of the unbalance masses (24) on the unbalance shafts (23) + position of the unbalance exciter (15) on a ground contact element (13) which acts on the soil to be compacted + excitation frequency + unbalance adjustment angle + position of components of the soil compaction device relative to one another + stiffness of a vibration decoupling device (21) which acts between components of the soil compaction device.

4. Soil compaction device according to one of the preceding claims, wherein the soil compaction device is a vibrating plate (10) with - an upper mass (12); - a lower mass (11) coupled to the upper mass (12) via a vibration decoupling device (21); and with - a ground contact element (13) belonging to the lower mass (11); and wherein - the vibration excitation device (14) is formed on the lower mass (11).

5. Soil compaction device according to one of the preceding claims, wherein - the soil compaction device is a rammer for soil compaction; - the rammer has a drive which has the vibration excitation device; - the vibration excitation device is provided for generating a translational oscillation movement which can be transmitted to a ground contact element; and wherein - a spring device is provided for transmitting the translational oscillation movement to the ground contact element; and wherein - the variable parameters are selected from the group + amplitude of the oscillation movement + frequency of the oscillation movement + transmission effect of the spring device.

6. Soil compaction device according to one of the preceding claims, wherein the soil compaction measuring device is designed to detect the compaction state of the soil based on a movement behavior of components of the soil compaction device.

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