EP1429871A1

EP1429871A1 - Vibration generator for a soil compacting device

Info

Publication number: EP1429871A1
Application number: EP02774662A
Authority: EP
Inventors: Franz Riedl
Original assignee: Wacker Construction Equipment AG
Current assignee: Wacker Construction Equipment AG
Priority date: 2001-09-28
Filing date: 2002-09-27
Publication date: 2004-06-23
Anticipated expiration: 2022-09-27
Also published as: DE50202732D1; US20040103730A1; JP2005504199A; JP3914919B2; DE10147957B4; US7117758B2; DE10147957A1; WO2003028905A1; EP1429871B1

Abstract

The invention relates to vibration generator for a soil compacting device referred to as a towed vibrating device . The vibration generator has two parallelly arranged unbalanced shafts (1, 2) that each support a fixed (6, 7) and a freely rotating unbalanced mass (8, 9). An unbalance adjusting device (10) enables the position of both freely rotating unbalanced masses (8, 9) to be adjusted in such a manner that, during a maximum unbalance action of one of the unbalanced shafts (2), the unbalance action on the other unbalanced shaft (1) is minimized. The unbalance adjusting device (10) can alter the position of the unbalanced masses (8, 9) whereby rendering possible a to-and-fro movement of the soil compacting device or a compaction when stationary.

Description

Vibration exciter for a soil compaction device

The invention relates to a vibration exciter for a soil compaction device.

Vibration plates known as "drag oscillators" are known for compacting soils. In the case of drag transducers, a vibration exciter is located off-center on a floor contact plate. The vibration exciter is usually a rotating unbalanced shaft. The unbalance or centrifugal force generated by the unbalance shaft tears the ground contact plate - since it is arranged off-center - up and forward on one side before it pushes the contact plate down again, thereby introducing the compaction energy into the ground. The very simple vibration exciter is therefore not only able to generate the vibration required for soil compaction, but also to move the soil contact plate forward.

Such drag transducer plates have excellent running behavior, especially on difficult soils with a high clay content and water content. It is precisely on such cohesive soils that other types of vibrating plates can cause difficulties in locomotion. The reason for the advantageous behavior of drag transducer plates is due to a comparatively large amplitude of the vibration exciter and to the presence of a constant reaction moment which, with a suitable direction of rotation of the unbalanced shaft, permanently causes a certain friction at the end of the ground contact plate opposite the vibration exciter.

A disadvantage of this type of construction, however, has been the fact that no continuous reversing, that is to say moving the vibrating plate back and forth, with the possibility of point compression, that is to say targeted compression at one point without forward movement of the vibrating plate, is possible with cost-effective means.

It is possible to arrange unbalanced shafts at both opposite ends of the ground contact plate and to drive only one of the two for the forward or reverse. However, the unbalanced shafts for standing work for point compression and for the transition from forward to return must be operated synchronously with twice the effort and precise speed, which requires considerable energy and control effort. The invention is based on the object of specifying a vibration exciter for soil compaction, in which on the one hand the advantageous principle of the so-called drag oscillator is maintained and on the other hand enables the soil compaction device to be moved forwards and backwards and to be compacted at a standstill.

According to the invention, the object is achieved by a vibration exciter with the features of claim 1. Advantageous further developments of the invention can be found in the dependent claims.

A vibration exciter according to the invention for a soil compaction device has two unbalanced shafts, which are coupled to one another in a form-fit, rotatable manner, each of which firmly supports a first unbalanced mass and a second unbalanced mass which can be rotated on the unbalanced shaft at least between two extreme positions. It is therefore possible for each unbalanced shaft to adjust the second unbalanced mass carried by it in such a way that its unbalanced effect either coincides with the effect of the fixed first unbalanced mass and thus reinforces it, or counteracts the effect of the first unbalanced mass and thus largely or completely compensates for it.

According to the invention, an unbalance adjustment device is provided, which couples the second unbalanced masses on the first and the second unbalanced shaft in a form-fitting and counter-rotating manner. The unbalance adjustment device makes it possible to adjust the unbalance effects of the first and second unbalanced shafts in such a way that - in extreme cases - only one of the unbalanced shafts generates an unbalanced load with the unbalanced masses carried by it, while the unbalanced effects of the unbalanced masses on the other unbalanced shaft compensate so that there is no imbalance. It is therefore possible to change the so-called "mr value", the product of the unbalance mass and the unbalance radius, of the unbalance masses installed on the two unbalanced shafts arranged in parallel in such a way that at the respective maximum of the one unbalanced shaft the other unbalanced shaft has a minimum mr value ideally even zero.

At these respective extreme positions, the pure drag oscillator effect is achieved, as it also occurs with known drag transducer plates, which only have one

Have vibration exciters with a single unbalanced shaft. This effect can be achieved even though both unbalanced shafts are rotating, which is of great importance for the bearing life, since the bearings are not subjected to static loads from one side.

Any other intermediate positions for the two second unbalanced masses can also be set between the two extreme positions. As a result, the soil compaction device carrying the vibration exciter according to the invention can be moved back and forth comfortably.

If the unbalance effect of the two unbalance shafts is the same, punctual standing work is possible with the soil compaction device, with a maximum of a dithering vibration effect that is particularly effective for compaction. The ground contact plate alternates between front and rear, which enables particularly effective soil compaction.

In an advantageous further development of the invention, the vibration excitation system described above is provided twice axially next to one another. Each unbalanced shaft carries two axially offset first unbalanced masses and two associated rotatable second unbalanced masses. The two additional (further) second unbalance masses on the first and the second unbalance shaft are positively coupled to one another by a second unbalance adjustment device in the same way as the two original second unbalance masses.

If the two unbalance adjustment devices can be controlled separately from one another, it is possible to generate a yaw moment about the vertical axis of the vibration exciter and thus the vertical axis of the soil compacting device, which allows the soil compacting device to be steered.

A steering device is advantageously provided with which the two unbalance adjustment devices can be controlled.

Another particularly advantageous further development of the invention attempts to keep the center distance between the two unbalanced shafts as large as possible. For this purpose, between the two unbalanced shafts there are two intermediate shafts which are rotatably coupled and which transmit the rotational movement of the driven first unbalanced shaft to the second unbalanced shaft. Due to the large distance between the two unbalanced shafts, the drag and compression effect can be increased. Of course, by arranging further pairs of intermediate shafts, the center distance between the two unbalanced shafts can be increased even more.

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

Figure 1 is a schematic sectional view in plan view of a vibration exciter according to the invention.

2 shows a schematic side view of the force vectors generated by the individual unbalanced masses and the directions of movement resulting therefrom;

3 shows a second embodiment of the invention with a vibration exciter for the steerability of a soil compaction device; and

Fig. 4 shows a third embodiment of the invention with a vibration exciter with an enlarged center distance between the two

Unbalanced shafts.

1 shows a first embodiment of a vibration exciter according to the invention, with a first unbalanced shaft 1 and a second unbalanced shaft 2.

The first unbalanced shaft 1 is in a known manner by a drive 3, z. B. a hydraulic motor or a coupling with an internal combustion engine, not shown, driven in rotation.

The first unbalanced shaft 1 is coupled to the second unbalanced shaft 2 in a form-locking manner in opposite directions via two gear wheels 4 and 5. This means that the first and the second unbalanced shaft 1, 2 rotate against each other.

A first unbalanced mass 6 is arranged on the first unbalanced shaft 1, while the second unbalanced shaft 2 carries a first unbalanced mass 7. The first unbalanced masses 6, 7 can be connected in one piece to the unbalanced shaft 1, 2 carrying them. It is also possible to use the first unbalanced masses 6, 7 z. B. with Fasten the screws on the unbalanced shafts 1, 2.

Furthermore, the first and the second unbalanced shaft 1, 2 each carry a second unbalanced mass 8, 9, which is not, however, firmly connected to the unbalanced shaft carrying it, but is rotatably held by the latter. The second unbalanced masses 8, 9 are each freely rotatable on the first or second unbalanced shaft 1, 2. It is also possible to implement only limited rotatability, which should, however, extend at least over a range of 180 °.

The two second unbalanced masses 8, 9 are coupled to one another in a form-locking manner in opposite directions by an unbalance adjusting device 10.

The unbalance adjustment device 10 has two gear wheels 11 and 12, the gear wheel 11 being firmly connected to the second unbalanced mass 8 of the first unbalanced shaft 1, while the gear wheel 12 meshing with the gear wheel 11 is firmly attached to the second unbalanced mass 9 on the second unbalanced shaft 2 connected is.

The gear 11 can be freely rotated together with the second unbalanced mass 8 on the first unbalanced shaft 1. In contrast, a twisting device 13 is provided as part of the unbalance adjusting device 10 on the second unbalanced shaft 2, with which the relative position between the second unbalanced mass 9 or the gear 12 on the one hand and the second unbalanced shaft 2 on the other hand can be precisely adjusted.

The rotating device 13 is known per se in its construction and mode of operation. It has a hydraulically or pneumatically actuated piston-cylinder unit 14, with which an adjusting element 15 can be moved axially back and forth inside the second unbalanced shaft 2.

The actuating element 15 carries a pin 16 which penetrates grooves 17 in the second unbalanced shaft 2 and engages in spiral grooves 18 which is formed on the inside of a hub carrying the second unbalanced mass 9.

This structure means that when the adjusting element 15 is axially displaced by the piston-cylinder unit 14 by means of the pin 16, the second unbalanced mass 9 is rotated relative to the second unbalanced shaft 2. This rotation is transmitted by the gears 12 and 11 in the opposite direction to the second unbalanced mass 8 on the first unbalanced shaft 1.

It is thus possible to use the unbalance adjustment device 10 to adjust the two second unbalanced masses 8, 9 in such a way that they either counteract the first unbalanced masses 6, 7 (shown in the lower half of the figure in FIG. 1 by the position of the unbalanced masses 6, 8) or intensify the effect of the first unbalanced mass (represented in the upper half of the figure by the unbalanced masses 7, 9).

However, as shown in FIG. 1, the adjustment is made in such a way that only one pair of unbalanced masses on one unbalanced shaft achieves a maximum unbalanced effect, while at the same time the unbalanced masses on the other unbalanced shaft compensate for their effect. This allows the drag oscillator principle to be retained. The unbalanced shaft, which has no unbalanced effect, simply runs along without impairing the effect of the unbalanced shaft which generates the actual vibration. The fact that the "deactivated" unbalanced shaft rotates, so to speak, prevents one-sided loading of the shaft bearings.

A change in the state by the unbalance adjustment device 10 causes the unbalanced shaft, which is initially ineffective, to generate an unbalance, while the unbalance of the other unbalanced shaft is reduced and finally goes to zero. A change in direction of the drag transducer can thereby be achieved.

2 shows different positions for the unbalanced shafts 1, 2 or the unbalanced masses 6 to 9.

In picture part a) of FIG. 2, the state is shown that was already recognizable in the top view of FIG. 1. While the effects of the unbalanced masses 7, 9 on the second unbalanced shaft 2 complement one another, the effects of the unbalanced masses 6, 8 on the first unbalanced shaft 1 are compensated for. The result is that a ground contact plate 19 carrying the vibration exciter moves to the left. Due to their eccentric arrangement, the unbalanced masses 7, 9 cause the ground contact plate 19 to be lifted off on one side, so that the ground compaction device moves to the left in FIG. 2a). An intermediate position is shown in FIG. 2b). While the unbalanced shafts 1, 2 and the first unbalanced masses 6, 7 which they firmly support have remained unchanged compared to FIG. 2a), the second unbalanced masses 8, 9 were rotated relative to the unbalanced shafts 1, 2 with the aid of the unbalanced mass adjustment device 10. Both unbalanced shafts 1, 2 now achieve an approximately equal unbalance effect, but which is directed alternately upwards and downwards. This creates the tilting vibration effect, which is very effective for compaction when stationary. The soil contact plate 19 or the entire soil compaction device does not move.

Fig. 2c) corresponds to an inversion of the state of Fig. 2a). Here, the unbalanced masses 6 and 8 of the first unbalanced shaft 1 are set such that their effects are superimposed, while the effects of the unbalanced masses 7, 9 on the second unbalanced shaft 2 are compensated for. A movement in the opposite direction (in Fig. 2c) to the right) is the result.

3 shows a top view of a second embodiment of the invention in a schematic sectional illustration.

In principle, the second embodiment corresponds to a doubling, i. H. Side by side arrangement of the first embodiment according to FIG. 1. For simplification, the same reference numerals are therefore used for the components already known from FIG. 1.

The first unbalanced shaft 1 now carries a further first unbalanced mass 20 in addition to the first unbalanced mass 6, while the second unbalanced shaft 2 carries a further first unbalanced mass 21 in addition to the first unbalanced mass 7. Likewise, the first unbalanced shaft 1 carries a second unbalanced mass 22 in addition to the second unbalanced mass 8 and the second unbalanced shaft 2 carries a further second unbalanced mass 23 in addition to the second unbalanced mass 9.

Just as the second unbalance masses 8, 9 are coupled to one another in a form-locking, counter-rotating manner by the unbalance adjustment device 10, the other second unbalance masses 22 and 23 are also rotatably coupled to one another by a second unbalance adjustment device 24. The functioning of the second unbalance adjustment device 24 corresponds to that of the first unbalance adjustment device 10, so that a detailed description can be dispensed with. The rotational coupling of the two unbalanced shafts 1 and 2 takes place as in FIG. 1 by means of the gear wheels 4, 5.

A separate controllability of the two unbalance adjustment devices 10 and 24 makes it possible to generate different resulting forces for the interacting unbalances. As a result, a yaw moment can be generated about the vertical axis of the vibration exciter (which is perpendicular to the plane of the drawing in FIG. 3) and thus also about the vertical axis of the soil compacting device, with the aid of which the soil compacting device can be steered.

The interaction of the two unbalance adjustment devices 10 and 24 is advantageously coordinated by a steering device, not shown, which can be easily handled by the operator.

Fig. 4 shows a third embodiment of the invention, in which the center distance of the two unbalanced shafts 1 and 2 has been increased. Since the two unbalanced shafts 1 and 2 and the unbalanced masses 6 to 9 carried by them correspond in principle to the first embodiment according to FIG. 1, the description is not repeated.

Between the gears 4 and 5 of the unbalanced shafts 1 and 2, two intermediate shafts 25 and 26 are inserted, which in turn carry gears 27, 28 and thus transmit the rotational movement of the first unbalanced shaft 1 to the second unbalanced shaft 2. In the same way, between the gears 11 and 12 of the unbalance adjustment device 10 gears 29 and 30 are inserted, which are carried by the intermediate shafts 25, 26, but can be freely rotated thereon.

With this arrangement, the center distance between the two unbalanced shafts 1 and 2 can be increased considerably, which makes it possible to also increase the distance between the unbalanced shafts 1, 2 and the center. This can improve the towing effect.

Of course, the second and third embodiments of the invention according to FIGS. 3 and 4 can be combined with one another for a large drag oscillator.

Claims

Patent claims

1. Vibration exciter for a soil compaction device, with a first unbalanced shaft (1) which can be driven in rotation, with which a first unbalanced mass (6) is firmly connected and on which a second unbalanced mass (8) is rotatably held relative to the unbalanced shaft (1) that the second unbalanced mass (8) can be rotated at least between two extreme positions in which its unbalanced effect increases or decreases that of the first unbalanced mass (6); - One with the first unbalanced shaft (1) positively rotatably coupled second unbalanced shaft (2), with which a further first unbalanced mass (7) is firmly connected and on which a further second unbalanced mass (9) can be rotated relative to the unbalanced shaft (2) it is held that the second unbalanced mass (9) can be rotated at least between two extreme positions in which its unbalanced effect increases or decreases that of the first unbalanced mass (7); and with an unbalance adjustment device (10) coupling the second unbalanced masses (8, 9) of the first and second unbalanced shafts (1, 2) in a form-locking manner that rotates in opposite directions; the positions of the second unbalanced masses (8, 9) can be adjusted by the unbalance adjusting device (10) such that when the unbalanced effects of the first and second unbalanced masses (6, 8) on the first unbalanced shaft (1) become one Compensate for the minimum unbalance value, the unbalance effects of the first and second unbalance masses (7, 9) on the second unbalance shaft (2) add up to a maximum unbalance value, and vice versa.

2. Vibration exciter according to claim 1, characterized in that any intermediate positions for the second unbalanced masses (8, 9) can be set by the unbalance adjustment device (10) between the extreme positions defined in claim 1.

3. Vibration exciter according to claim 1 or 2, characterized in that the unbalance adjustment device (10) has a hydraulic or pneumatically actuable piston-cylinder unit (14).

4. Vibration exciter according to one of claims 1 to 3, characterized in that with an adjustment to the minimum unbalance value there is almost no unbalance effect from the unbalanced shaft (1, 2) in question.

5. Vibrator according to one of claims 1 to 4, characterized in that the first unbalanced shaft (1) carries an axially next to the first unbalanced mass (6) arranged further first unbalanced mass (20) and a further rotatable second unbalanced mass (22); the second unbalanced shaft (2) carries a further first unbalanced mass (21) arranged axially next to the first unbalanced mass (7) and a further rotatable second unbalanced mass (23); and that a second unbalance adjustment device (24) is provided for coupling the further second unbalanced masses, which can be rotated in a form-locking manner in opposite directions

(22, 23).

6. Vibration exciter according to claim 5, characterized in that a steering device is provided for controlling the two unbalance adjustment devices (10, 24).

7. Vibration exciter according to one of claims 1 to 6, characterized in that the positive rotary coupling between the first and the second unbalance shaft (1, 2) and the one unbalance adjustment device (10) or the two unbalance adjustment devices (10, 24) have two positively rotatably coupled Have intermediate shafts (25, 26) to enlarge the center distance between the first and the second unbalanced shaft (1, 2).