WO2004022250A1

WO2004022250A1 - Vibration exciter for soil compacting devices

Info

Publication number: WO2004022250A1
Application number: PCT/EP2003/009822
Authority: WO
Inventors: Franz Riedl
Original assignee: Wacker Construction Equipment Ag
Priority date: 2002-09-05
Filing date: 2003-09-04
Publication date: 2004-03-18
Also published as: EP1534439A1; HK1082458A1; EP1534439B1; US20060067796A1; JP2006501049A; CN1678410A; CN100348339C; DE50306207D1; JP4314194B2; DE10241200A1

Abstract

A vibration exciter for soil compacting devices, e.g. for a vibration plate, comprises unbalanced shafts (2, 3). These unbalanced shafts are parallel or coaxial to one another, can be driven in opposite directions with the same rotational speed, and each supports a stationary unbalanced mass (4, 5, 16, 17) and an unbalanced mass (6, 18) that can rotatably move relative to the unbalanced shaft (2, 3). The relative position of a respective moving unbalanced mass (6, 16) with regard to the unbalanced shaft (2, 3) supporting the same can be adjusted by an adjusting device (9, 19) so that the centrifugal forces produced by the unbalanced masses during the rotation of the unbalanced shafts (2, 3) are entirely canceled out in every position of rotation of the unbalanced shafts (2, 3). This makes it possible, among other things, to effect a change in the relative position so that the magnitude of a total centrifugal force resulting from the unbalanced masses is proportional to an advancing speed of the soil compacting device.

Description

Vibration exciter for soil compaction equipment

description

The invention relates to a vibration exciter for a soil compacting device according to the preamble of claim 1.

Such vibration exciters are mainly used advantageously with vibration plates and are such. B. is known from EP 0 358 744 B1.

A similar vibration exciter is described in DE 100 38 206 AI. It has two unbalanced shafts coupled in a form-locking, counter-rotating manner, each of which carries a fixed unbalanced mass and an unbalanced mass which is rotatable relative to the fixed unbalanced mass and thus rotatable with the unbalanced shaft. The position of the moving unbalanced masses can be actively changed over a wide range by setting directions.

When the unbalance shafts rotate, the interaction of the various unbalance masses results in a total force that can be directed in the forward or reverse direction of travel, depending on the operator's request. The change in the direction of travel is brought about by the control devices that control the movable unbalanced masses. If the operator wishes the soil compactor to stop, the resulting force of the flyweights is set in the vertical direction. This also means that a targeted compaction of the soil can be achieved when the machine is stationary.

However, the operator does not always want such a high level of compaction at a locally restricted location on the ground. In particular when moving the vibrating plate back and forth, an excessively strong and thus disadvantageous compaction of the soil can be achieved in the so-called reversing or reversing point, since the force acting on the soil is greatest in this position, while it is in the forward or Reverse travel of the vibration plate and the associated pivoting of the resulting force vector reduced for example by 45 ° forwards or backwards to 1 / V2 of the maximum value.

Even if the arrangements described have proven to be extremely effective in soil, sand or gravel compaction, they can prove problematic in the compaction of asphalt or composite stone surfaces, as the maximum vertical force prevailing at the reservation point allows for punctual settlement can occur that can no longer be corrected. In the case of asphalt rollers, the vibration is therefore usually switched off in reversing operation in order to prevent the roller from penetrating too deeply into the asphalt when the direction is reversed.

To solve this problem, a vibration exciter is described in DE 199 43 391 AI, in which the phase position of the centrifugal weights can be set such that the vertical components of the centrifugal forces generated by the centrifugal weights cancel each other, while the horizontal components of the centrifugal forces add up in the same direction , This makes it possible for the vibration plate to no longer introduce vertical vibrations into the ground when standing, but rather to introduce shear stresses into the ground via a ground contact plate, with which e.g. B. cracks and pores can be compacted in an advantageous manner on an asphalt surface.

This arrangement has also proven itself in practice. However, the strong horizontal vibrations prevailing when the vibrating plate is stationary are not always pleasant for the operator and are also not always desirable for compacting the surface of the ground.

The invention is therefore based on the object of further developing a vibration exciter of the aforementioned type such that an excessively strong compaction of the soil in stationary operation due to strong vertical vibrations can be avoided without the operator or the soil to be compacted being exposed to strong horizontal vibrations in return.

The object is achieved by a vibration exciter with the features of claim 1. Advantageous further developments are defined in the dependent claims.

A vibration exciter according to the invention preferably has two unbalance shafts which are parallel to one another and can be driven in opposite directions at the same speed, each of which carries a fixed unbalanced mass and an unbalanced mass which is rotatable relative to the fixed unbalanced mass or the respective unbalanced mass. Each of the unbalanced shafts is assigned an EmsteU device, with which the relative position of the respective movable unbalanced mass with respect to the unbalanced shaft carrying it can be adjusted. According to the invention, the relative positions of the movable unbalance masses with respect to the Balancing shafts can be set in such a way by the control units that the centrifugal forces generated by the unbalanced masses when the unbalanced shafts rotate cancel each other out in every rotational position of the unbalanced shafts. This means that each unbalanced mass creates a centrifugal force; however, the centrifugal forces are adjusted in terms of direction and amount so that they compensate for the total. The vibration exciter therefore does not generate any vibrations in this operating state (standing position), even though the unbalanced shafts rotate.

This can be achieved in a particularly advantageous manner that the size of the resulting total force, i. H. the vibration strength, depending on the speed of movement of the vibrating plate. If the speed is reduced, the effective centrifugal force is reduced in a corresponding ratio up to the standstill of the machine, at which there is no resulting total centrifugal force and therefore no vibration. In this way, a very uniform energy input into the soil can be achieved over the area to be compacted.

In a special embodiment of the invention, the relative position on each of the unbalanced shafts can be adjusted in such a way that the centrifugal forces of the unbalanced masses carried by this unbalanced shaft cancel each other out of the unbalanced shaft. This means that even with operation with only one unbalanced shaft, a relative position can be reached in which there is no vibration effect.

In order to achieve a movement of the soil compaction device as in known devices, the relative positions can be changed in a preferred embodiment of the invention such that the centrifugal forces of the unbalanced masses do not cancel each other out, but rather that a resulting total centrifugal force has a horizontal component. This allows the vibratory plate to move, as is known from the prior art.

When changing direction between z. B. a forward and a backward direction of travel is temporarily the position already described in which no vibration acts in the ground. Unwanted vertical or horizontal vibrations can thus be avoided even when changing direction at the reversing point. Because the adjustment of the movable unbalanced masses is sufficient to generate the resulting centrifugal force with the desired direction and size, it is not necessary in a preferred embodiment that the phase position of the unbalanced shafts must be mutually changeable, as z. B. in the case of the vibration exciter described in DE 100 38 206 AI.

The term "unbalance mass" is meant abstractly in connection with this description. Of course, an unbalanced mass can also consist of several unbalanced elements which are distributed on the respective unbalanced shaft.

These and other advantages and features of the invention are explained in more detail below with the aid of the accompanying figures. Show it:

1 shows a section in plan view through a vibration exciter according to the invention in the standing position; and

Fig. 2 schematic sections through two unbalanced shafts in different rotational positions with the respective positions of the unbalanced masses.

As already mentioned, vibration exciters in various forms are known. Likewise - such. It is known, for example, from DE 199 43 391 AI - so-called "phase control devices", that is to say setting devices for adjusting relative positions between unbalanced masses and unbalanced shafts. Since the invention does not provide the detailed and specific design of a specific vibration exciter or a specific setting device, Rather, it concerns a relative position (phase position) that is particularly suitable for this but not yet known, a detailed description of the vibration exciter is not necessary.

Nevertheless, the structure of a vibration exciter according to the invention will be briefly described with reference to FIG. 1.

Two unbalanced shafts 2, 3 are rotatably mounted in a housing 1, the unbalanced shaft 2 being driven in rotation by a drive (not shown).

The unbalance shaft 2 carries unbalance elements 4 and 5, which with the unbalance shaft 2 are firmly connected and form a fixed unbalanced mass.

Furthermore, a rotatably movable unbalanced mass 6 is arranged on the unbalanced shaft 2, which can be rotated relative to the unbalanced shaft 2 via a hub 7 and bearing 8.

The relative position between the movable unbalanced mass 6 and the unbalanced shaft 2 is determined with the aid of an control device 9. The operating principle of such a EinsteUeinrichtung has long been known and z. B. described in DE 100 38 206 AI. The adjusting device 9 essentially has a piston 10 which is axially adjustable under hydraulic action and can be moved axially back and forth in a hollow region of the unbalanced shaft 2. The piston 10 carries a transverse pin 11 which penetrates two longitudinal grooves 12 formed in the wall of the unbalanced shaft 2 and engages in spiral grooves 13 which are formed on the inside of the hub 7. When the piston 10 and thus the transverse bolt 11 are axially adjusted, the hub 7 and the movable unbalanced mass 6 carried by it thus rotate relative to the unbalanced shaft 2.

The unbalanced shaft 2 also carries a gear 14 which meshes with a gear 15 which is attached to the unbalanced shaft 3. Via the gears 14 and 15, the rotational movement of the driven unbalanced shaft 2 is positively transmitted to the unbalanced shaft 3, which thus rotates in opposite directions but at the same speed.

In the same way as the unbalanced shaft 2, the unbalanced shaft 3 carries two unbalanced elements 16, 17, which together form a fixed unbalanced mass. Furthermore, an unbalanced mass 18, which is rotatable on the unbalanced shaft 3, is provided, the relative position of which with respect to the unbalanced shaft 3 can be adjusted via an adjusting device 19. Since the control unit 19 has the same structure as the control unit 9, a detailed description is omitted.

The control of the unbalanced mass shown in the section of FIG. 1 corresponds to the relative control according to the invention, in which the individual forces generated by the respective unbalanced masses or elements cancel each other out (standing control). This means that the unbalance effect of the unbalance elements 4, 5 or 16, 17 on the one hand and the unbalance effect of the moving unbalance masses 6, 18 on the other hand must be identical in terms of amount, but opposite. The associated mr values (products from mass mx radius r of the unbalance center of gravity) must be coordinated accordingly.

As a result, the unbalance weights 2 and 3 can rotate without an out-of-balance effect and thus an oscillation occurring. When the movable unbalance masses 6, 18 are adjusted by the control devices 9, 19, however, this state of equilibrium is canceled, so that the desired vertical and horizontal vibrations for soil compaction can occur.

The various relative controls and the resulting vibration states are shown in FIG. 2. FIG. 2 shows highly schematic side views from the right in FIG. 1.

The hatched semicircles correspond to the movable, thus understandable, unbalanced masses 6, 18, while the non-hatched semicircles correspond to the unbalanced masses 4, 5 and 16, 17 which are fixed with respect to the unbalance weights 2, 3, as described for B. in the field a) "Stand" of Fig. 2 can be seen.

The state shown in FIG. 1 is accessed in section a) of FIG. 2 under the heading "Stand". The direction of rotation of the unbalanced masses 2, 3 and thus the unbalanced masses is shown by a crooked Pfeüe. The fixed unbalanced masses 4, 5 and 16, 17 are each opposite the moving unbalanced masses 6, 18.

In the lines a) to d) different states of rotation of the unbalance paths 2, 3, each rotated by 90 °, are shown. The direction of rotation of the unbalance shafts 2, 3 is of course the same every time.

In order to achieve a forward movement of the vibrating plate (Unke column of FIG. 2), the moving unbalanced masses 6, 18 are rotated with respect to the fixed unbalanced masses 4, 5 and 16, 17, respectively.

In the example shown, the movable unbalanced mass 6 has been rotated by 90 ° relative to the fixed unbalanced elements 4, 5 and the unbalanced weight 2. In addition, the movable unbalanced mass 18 was rotated by 90 ° in the same direction as the movable unbalanced mass 6 with respect to the fixed unbalanced elements 16, 17 on the unbalanced weight 3. The corresponding state is in Fig. 2a) shown in the column "Forward". Also here in the column 'Forward' under a) to d) different states of rotation of the unbalance weights 2, 3 are shown.

It can be seen that due to the unbalanced masses 4, 5 on the one hand and 6 on the other hand, the executives no longer compensate each other, as was the case with the vibrating stand. Rather, the guide forces are superimposed in such a way that a resulting force shown in FIG. A) results to the top left, which corresponds to the forward direction.

in Fig. 2c) there is a corresponding counteraction to the bottom right. In this FaU, the vibration plate is supported on the ground and introduces the vibrational energy into the ground.

A backward movement of the vibrating plate (to the right in Fig. 2) is shown in the right column of Fig. 2. For this purpose, the moving unbalance masses 6 and 18 with respect to the unbalance weights 2, 3 carrying them have been rotated by 90 ° in the opposite direction to the forward direction and in relation to the stand control, as can be seen in FIG. 2a) in the "Backward" column.

As a result, as shown in FIGS. A) and c) "backwards" by a straight paw, an oscillation of the vibration plate to the top right and bottom left is achieved, which results in a backward travel.

The controls of the unbalanced masses shown in FIG. 2 are extreme controls. Depending on the extent to which the control devices 9, 19 are used, other intermediate positions, i. H. Control angle other than 90 ° can be reached, so that a continuous change between forward travel, stationary operation and reverse travel can be achieved.

For the control devices 9, 19 it is possible, on the one hand, to use known means such as hydraulic control, electric motors, electromechanical control devices, etc. Alternatively, in a simplified embodiment, the moving unbalanced masses can also be controlled with the aid of simple push-pull cables which can be controlled by the operator via a common transmitter. This can save considerable costs even with simpler vibratory plates. In order to achieve a precise change between the individual operating states, the control of the relative controls by the control devices 9, 19 should be able to be carried out synchronously. In some cases, however, it may also be expedient to enable the movable unbalanced masses to be individually controlled without the need for synchronization.

The continuous change between driving forwards and backwards, in which the stationary operation can be assumed temporarily without generating vibrations, makes it possible for the amount of the resulting driving force and thus the effective vibration to be adjustable in proportion to the speed of travel of the vibrating plate. The slower the vibrating plate moves, the lower the resulting force until the vibrating plate is at a standstill, e.g. B. at the reversing point, no more vibration is introduced into the ground. This proportional dependency results from the structure of the vibration exciter according to the invention, without the need for complex control measures.

It goes without saying that it is also possible with the vibration exciter according to the invention to assume other relative controls than those shown in FIG. 2. With an appropriate exhaustion of the EinsteUeinrichtung 9, 19 z. B. RelativsteUungen achieve, in which no vertical vibrations, but strong horizontal vibrations are generated when the vibrating plate is stationary, as known in DE 199 43 391 AI.

The invention has been explained using the example of a vibration exciter according to FIG. 1. Of course, the principle underlying the invention can also be applied to other vibration exciters which, for. B. have several moving unbalanced masses or a different number of unbalanced masses.

Claims

Patent claims

1. Vibration exciter for soil compacting devices, with paraUel or coaxial to each other, in opposite directions drivable with the same speed unbalance weights (2, 3), each of the unbalance weights (2, 3) a fixed unbalance mass (4, 5; 16, 17) and carries an unbalanced mass (6, 18) which is rotatable relative to it, and wherein each of the unbalanced masses (2, 3) has an control device (9, 19) for controlling the relative control of the respective movable unbalanced mass (6, 18) with respect to the unbalanced mass carrying it (2, 3), characterized in that the relative controls can be set by the control devices (9, 19) in such a way that when the unbalance weights (2, 3) rotate, the unbalanced masses (4, 5; 16, 17; 6, 18) cancel the generated forces in each rotation control of the unbalance units (2, 3) in their entirety.

2. Vibration exciter according to claim 1, characterized in that the relative control on each of the unbalance weights (2, 3) can be set such that the forces of the unbalance weights (4, 5, 6; 16, 17, 18) carried by this unbalance weight cancel each rotation control of the unbalance.

3. Vibration exciter according to claim 1 or 2, characterized in that in order to bring about a movement of the soil compacting device in a horizontal first direction, the relative controls can be changed in such a way that the leading forces of the unbalanced masses do not cancel each other out, but rather a total leading force resulting from the leading forces is a horizontal component having.

4. Vibration exciter according to claim 3, characterized in that when changing between the first direction and an opposite second direction, the relative controls defined in claim 1 can be temporarily assumed.

5. Vibration exciter according to one of claims 1 to 4, characterized in that a change in the RelativsteUungen can be carried out such that the amount of a total force resulting from the unbalanced mass is proportional to a locomotion speed of the soil compacting device.

6. vibration exciter according to claim 5, characterized in that the Change of the relative controls is continuously feasible.

7. Vibrator according to one of claims 1 to 6, characterized in that the UnwuchtweUen (2, 3) are positively rotatably coupled with each other.

8. vibration exciter according to one of claims 1 to 7, characterized in that the phase position of the UnwuchtweUen (2, 3) to each other is not changeable.

9. Vibration exciter according to one of claims 1 to 8, characterized in that the control of the relative controls by the control devices (9, 19) on the unbalance weights (2, 3) can be carried out synchronously.

10. Vibration exciter according to one of claims 1 to 9, characterized in that the setting devices (9, 19) can be actuated electrically, hydraulically, pneumatically or mechanically.

11. Vibrator according to one of claims 1 to 10, characterized in that at least a part of the unbalance masses is formed from a plurality of unbalance elements (4, 5; 16, 17).