EP0047433B1 - Vibration device for compacting materials, especially for soil compaction - Google Patents

Abstract

A material compacting vibration machine provided with an imbalanced system having coaxial first and second independently rotatable shafts carrying first and second drive elements and a pair of unbalanced masses having third and fourth drive elements secured thereto with driving connections between the first and third drive elements and between the second and fourth drive elements, and a drive shaft selectively coupled to the first and second drive elements, wherein the four drive elements all are disposed on one side of the imbalanced system and are shielded by a cover.

Description

The invention relates to a vibration device for material compaction, in particular a soil compaction device, which has an unbalance system with two coaxial shafts that can be driven independently of one another, each of which is connected to an unbalanced mass and a first or a second gear element, as well as a drive shaft and at least one switchable clutch for optional drive of a third or fourth gear element which is in drive connection with the first or the second gear element. The gear elements mentioned will usually be pulleys, gearwheels or the like, so that the drive connection is established by means of a V-belt or toothed belt, by direct meshing of the gearwheels with one another or by intermediate gears.

In a known vibration device of this type (DE-OS 1 558869), one of the two coaxial shafts is designed as a hollow shaft and it carries a half-shell-shaped unbalanced mass which overlaps the second unbalanced mass located on a core shaft, so that the two shafts together with the associated unbalanced masses are independent of one another can be driven. This drive takes place via a drive shaft running parallel to the two coaxial shafts, which drives a switchable clutch with which two pulleys rotatably mounted on opposite end regions of the drive shaft can optionally be connected. These drive one of the unbalanced masses via V-belts and pulleys attached to opposite end areas of the two coaxial shafts. Since the transmission ratios of the two pulley gears and the unbalance of the two unbalanced masses were chosen differently, the known vibration device can be operated with two different frequencies as well as with two different unbalances, although there is a fixed association between frequency and unbalance.

The known vibration device has various disadvantages: In order not to endanger the operator, it must be prevented that the operator can reach into the V-belt transmission mentioned or that the operator's clothing can be caught by the V-belt transmission; Therefore, two housing-like covers on both sides of the unbalance system are required in the known vibration device. Furthermore, one of the two unbalanced masses is ineffective in each operating mode, so that it only increases the weight of the vibration device.

The present invention has now created a vibration device of the type mentioned at the outset, which is simpler in construction and can be built more compactly than the known vibration device described, namely according to the invention the four gear elements serving to drive the two unbalanced masses are all on one side of the unbalance system arranged and covered by a cover. The vibration device according to the invention thus has a gearbox only on one side of the unbalance system, so that a cover is also required only on one side of the unbalance system. This not only makes the new vibration device cheaper to manufacture, it also makes it narrower and lighter.

In the case of vibratory soil compacting devices, it is already known (DE-AS 2108106) to arrange both gear elements in the form of pulleys and a switchable clutch on a drive shaft only on one side of an unbalance system, with the aid of which either one of the two pulleys with the drive shaft can be selected can be connected, but also in this known construction on both sides of the only one unbalanced mass and consequently only a single shaft unbalance system gear elements are arranged, namely two pulleys attached to the opposite ends of the unbalanced mass shaft and two also on the one another Pulleys attached to the opposite ends of an intermediate shaft, this intermediate shaft extending over the entire width of the unbalance system and serving to be able to drive the unbalanced mass in the direction opposite to the normal direction of rotation. In this known vibration device, the switchable clutch is therefore not used to change the frequency with which the unbalanced mass is operated, but rather to reverse the direction of rotation. The vibration device according to DE-AS 2108106 also has all the disadvantages of the vibration device according to DE-OS 1 558869, and its unbalance system does not have a truly one-sided drive.

In vibration devices with an unbalance system having two unbalanced masses, it is also known (DE-OS 2738794) to set different total unbalances in such a way that the unbalanced masses can be arranged and fixed relative to one another in different angular positions by means of a coupling.

To achieve the same effect, but without requiring complicated components such as couplings, it is now proposed according to the invention to design the unbalance system in such a way that the unbalanced mass not coupled to the drive shaft is carried along by the other unbalanced mass at least in one angular position of the two unbalanced masses and that for the angular position in which the unbalanced masses have the smaller angular distance from one another, together with the driven first unbalanced mass, a stop which carries the other, second unbalanced mass and which is arranged such that the first unbalanced mass is opposite leads the second unbalanced mass. In this connection, the following must be pointed out: It would not be sufficient simply to allow a stop for the other unbalanced mass to run along with the driven unbalanced mass; namely, in the state of greatest total unbalance, i.e. with substantially unbalanced masses of unbalanced mass, the larger unbalanced mass would be coupled to the drive and the smaller unbalanced mass would be taken along by a stop rotating together with the larger unbalanced mass such that they would rotate in the direction of rotation before the large one Imbalance mass, which would be the most obvious in itself, would have the consequence that the unbalanced mass taken would soon assume an angular position in which it is roughly opposite the driven unbalanced mass - such an unbalance system always endeavors to assume the state of lowest total unbalance, and When such a vibrating device strikes the ground, the smaller, unbalanced mass taken along would lead the larger unbalanced mass coupled to the drive. Therefore, the construction according to the invention provides that the driven unbalanced mass always leads the unbalanced mass. In this case, the unbalance system cannot change to the state of lowest total unbalance while continuously reducing the total unbalance, since a state would first have to be run through in which the total unbalance is greater than in the state in which the two unbalanced masses are at a smaller angular distance from one another and that driven unbalanced mass leads over the entrained unbalanced mass.

The vibrating device according to the invention thus allows the unbalance system to be operated with a large effective and with a small effective total unbalance when operating at a low frequency with a very simple structure. This is a great advantage for soil compaction equipment, since it is better to work hard soil with a high frequency and small amplitude in order to avoid damage to the vibrating device, whereas with soft soil such as clay, large jumps of the vibrating device at low frequency are desirable in order to get stuck of the vibrator on soft, damp floors.

For the state of smallest total unbalance, a stop to take the unbalanced unbalanced mass per se would not be necessary at all, since the unbalance system endeavors to assume this state anyway if one of the two unbalanced masses is driven and the other can rotate freely. However, so that when the shaft of the unbalance system assigned to the state of the smallest total unbalance is driven, the state of the smallest total unbalance is quickly assumed, a preferred embodiment of the vibration device according to the invention has a stop which takes the first unbalanced mass away from the angular position in which the unbalanced mass is at a greater angular distance from one another on.

Finally, a particularly simple structure for the coupling of the vibration device is also proposed; According to this proposal, the clutch for the connection of the two gear elements to the drive shaft should each have a clutch drum which are arranged next to one another in the axial direction and to which only a single switchable centrifugal weight clutch element which is non-rotatably connected to the drive shaft is assigned, and for switching over the Coupling, coupling element and coupling drums can be displaced relative to one another in the axial direction such that the coupling element can optionally be arranged within one of the coupling drums assigned to it. Compared to known switchable centrifugal clutches (e.g. DE-OS 2 509 322), a centrifugal weight coupling element can be saved.

A particularly space-saving clutch is obtained when the clutch drums are rotatably connected to one of the gear elements to be coupled to the drive shaft, are arranged in the axial direction between them and are rotatably mounted together with them on the drive shaft.

In an advantageous embodiment of the clutch according to the invention, a switching element which passes through the drive shaft in the axial direction is provided for the centrifugal weight coupling element which can be displaced along the drive shaft, so that the clutch drums can be made axially immovable. However, an embodiment is shorter in the axial direction, in which the clutch drums are non-rotatable relative to the respectively assigned gear element, but are displaceable in the axial direction and can thus be arranged optionally above the centrifugal weight coupling element. In this embodiment, the shift path lies between the two gear elements to be coupled to the drive shaft, so that the embodiment is shorter in the axial direction by the shift path length than the embodiment described in the first place, in which as much space is required beyond the one gear element as that Movement of the switching element corresponds to the switching path length.

In the second embodiment described above, it is finally expedient to rotatably mount a switching element firmly connected to the latter in the axial direction on the clutch drums, in order to be able to push the clutch drums back and forth with a stationary switching element.

A particular advantage of the centrifugal clutch according to the invention is that it essentially consists of series products available on the market len known centrifugal clutches and can therefore be manufactured inexpensively.

• Fig. 1 eine Seitenansicht des als Bodenverdichtungsgerät ausgebildeten Vibrationsgeräts;
• Fig. 2 eine Frontansicht dieses Bodenverdichtungsgeräts;
• Fig. 3 eine schematische Darstellung des Unwuchtsystems und seines Antriebs bei Verwendung in dem Bodenverdichtungsgerät gemäss den Figuren 1 und 2;
• Fig. 4a
• Fig. 4b die Zustände grösster und kleinster Gesamtunwucht des Unwuchtsystems in einer schematischen Seitenansicht;
• Fig. 5 einen Axialschnitt durch das Unwuchtsystem gemäss der Linie 5-5 in Figur 1;
• Fig. 6 einen Querschnitt durch das Unwuchtsystem nach der Linie 6-6 in Figur 5;
• Fig. 7 einen Axialschnitt durch eine erste Ausführungsform einer erfindungsgemässen Fliehkraftkupplung;
• Fig. 8 einen Schnitt nach der Linie 8-8 in Figur 7, wobei jedoch nur das Fliehgewicht-Kupplungselement dargestellt wurde, und
• Fig. 9 einen Axialschnitt durch eine zweite Ausführungsform der erfindungsgemässen Fliehkraftkupplung.

Further features, advantages and details of the invention emerge from the appended claims and / or from the attached drawing and the following description of preferred embodiments of a vibration device according to the invention, an unbalance system according to the invention and a centrifugal clutch according to the invention; in the attached drawing show:

• 1 shows a side view of the vibration device designed as a soil compaction device;
• Fig. 2 is a front view of this soil compacting device;
• 3 shows a schematic illustration of the unbalance system and its drive when used in the soil compacting device according to FIGS. 1 and 2;
• Fig. 4a
• 4b shows the states of largest and smallest total unbalance of the unbalance system in a schematic side view;
• 5 shows an axial section through the unbalance system along the line 5-5 in FIG. 1;
• 6 shows a cross section through the unbalance system along the line 6-6 in FIG. 5;
• 7 shows an axial section through a first embodiment of a centrifugal clutch according to the invention;
• Fig. 8 is a section along the line 8-8 in Figure 7, but only the flyweight coupling element has been shown, and
• Fig. 9 shows an axial section through a second embodiment of the centrifugal clutch according to the invention.

Figures 1 and 2 show a soil compaction device designed according to the invention with a vibrating plate 10 on which an unbalance system 12 is attached. This is driven by an internal combustion engine 14 via a drive system 16. A tank in front of the engine was designated 18, a guide handle for the device attached to the vibrating plate 10 was designated 20.

As can be seen in FIG. 3, the motor 14 drives one of two pulleys 24, 26 via a drive shaft 19 and a centrifugal clutch 22. For this purpose, a clutch drum 28 or 30 is connected to each of the pulleys, within which is arranged an axially displaceable drive element 32, which is non-rotatably connected to the drive shaft 19 and which frictionally engages against that clutch drum 28 or, as the centrifugal weights increase, as the engine speed increases 30 creates within which it is currently located. By moving the drive element 32, it is thus possible to select which of the clutch drums and thus which of the pulleys 24, 26 is to be driven.

These pulleys are connected via V-belts 34 and 36 to pulleys 38 and 40, the first of which is connected in a rotationally fixed manner to a hollow shaft 42 and the second to a core shaft 44 which is concentric therewith.

The hollow shaft 42 carries a larger, the core shaft 44 a smaller unbalanced mass 46 or 48, so that the two shafts and the two unbalanced masses together form the unbalance system designated by 12 in FIGS. 1 and 2.

Since one of the two clutch drums 28, 30 can always rotate freely, the unbalanced mass 46 or 48 connected to the respective non-driven shaft 42 or 44 could assume any rotational angle position relative to the driven unbalanced mass. However, stops are now provided, which are arranged according to the invention in such a way that when the large unbalanced mass 46 is driven, the small unbalanced mass 48 is not taken along in any position, but in a position in which it lags slightly compared to the large unbalanced mass 46, as shown in FIG Figure 4a is shown. On the other hand, even for the state of the smallest effective total unbalance, in which the small unbalanced mass 48 is driven, a stop carrying the large unbalanced mass 46 is provided, in order to ensure that the larger unbalanced mass 46 is carried in the position in which it was moved from the beginning smaller unbalanced mass 48 is approximately diametrically opposite, as was shown in Figure 4b.

By appropriate selection of the diameters of the pulleys 24, 26, 38, 40 it can be achieved that the unbalanced masses 46 and 48 are driven at different speeds and the device runs at a low total frequency with a large total unbalance and at a high frequency with a small total unbalance.

Since, according to the invention, the entire transmission 24, 26, 38, 40, 34, 36 is located on one side of the unbalance system 12, only a single housing-like cover, which has been designated 50 in FIGS. 1 and 2, is required.

FIGS. 5 and 6 show a preferred embodiment of the unbalance system 12 according to the invention, in which the hollow shaft 42 is mounted in a housing 60 with the aid of roller bearings 62, while slide bearings 64 serve to support the core shaft 44.

According to the invention, a stop bar 46a is attached to the large unbalanced mass 46 such that when the hollow shaft 42 is driven or the large unbalanced mass 46 is driven, the small unbalanced mass 48 which is carried along lags slightly in the direction of rotation, as is shown in FIG. 6 with solid lines.

Furthermore, on one of the two unbalanced masses, in the illustrated embodiment also on the large unbalanced mass 46, a further stop bar 46b can be provided, through which the large unbalanced mass is driven when the core shaft 44 is driven so that it is diametrically opposed to the small unbalanced mass 48. This state is shown in dot-dash lines in FIG.

In the vibration device according to the invention the two states with the largest and smallest total unbalance are brought about with the simplest means, so that complicated parts such as switchable couplings in the unbalance system itself can be dispensed with.

FIG. 7 shows a drive shaft 110 provided with a drive flange 112, on which two pulley bodies 116 and 118 are rotatably but axially non-displaceably mounted with ball bearings 114 held axially immovable. Each of these pulley bodies forms a pulley 116a or 118a and a clutch drum 116b or 118b, the latter facing each other and having the same inside diameter according to the invention.

In the drive shaft 110, a switching axis 120 is held in the longitudinal direction; at its outer end it carries a shift lever 124 via a ball bearing 122 which is held immovably in the axial direction, while a tension pin 126 is fastened at its inner end, which extends through longitudinal slots 128 in the drive shaft 110 on both sides of the shift axis 120 and in one designated 130 as a whole Clutch disc protrudes. This clutch disc is available as a whole part on the market, e.g. from the company Robert Scheuffele & Co., D-7120 Bietigheim-Bissingen.

The clutch disc 130 has a disc body 132 on which the flyweights 136 provided with clutch linings 134 are held with the aid of springs 138 pulling the flyweights against each other in such a way that they can only move outward in the radial direction relative to the disc body 132.

By shifting the shift lever 124 in the axial direction, the clutch disc 130, which is non-rotatably connected to the drive shaft 110 via the dowel pin 126, can be shifted in the axial direction when the drive shaft 110 is at a standstill or only rotating at idling speed, and thus optionally within one of the clutch drums 116b and Arrange 118b so that when the speed of the drive shaft 110 increases, one of the two pulleys 116a or 118a is driven.

In the variant of the centrifugal clutch according to the invention according to FIG. 9, a clutch disk 130 'is fixedly attached to a drive shaft 110', ie it rotates with the drive shaft and is immovable relative to the latter. With the aid of ball bearings 114 'which are held immovably on the drive shaft 110', two pulley bodies 116 _' and 118' are again rotatable on the drive shaft, but are mounted immovably relative to the latter and each form a pulley 116a 'and 118a'.

In this embodiment, however, the clutch drums 116b 'and 118b' are not formed on the pulley bodies, but are formed as separate parts, which are connected in a rotationally fixed manner to the assigned pulley body via a ring of driving pins 150 'or driving wedges 152', but are opposed to it in Have it shifted axially.

A ball bearing 122 'is fastened on each of the clutch drums 116b' and 118b ', a shift lever 124' was fastened on the outer rings of these ball bearings, so that one of the two clutch drums 116b 'and 118b' can be selectively positioned with its help over the clutch disc 130 'can be pushed.

The same reference numerals as in FIGS. 7 and 8 were used for parts of the embodiment according to FIG. 9 not described above, but with the addition of an apostrophe.

Since in the second embodiment the space between the two pulleys required by the two clutch drums in the axial direction is used to accommodate the shifting path, the embodiment according to FIG. 9 is shorter in the axial direction than the embodiment according to FIG. 7.

Claims (9)

1. A vibration machine for compacting materials, in particular an earth compacting machine; comprising an imbalance system (12) with two coaxial shafts (42, 44) drivable independently of each other, each of said shafts being connected with an unbalanced mass (46, 48) and a first or second gear element (38 or 40), also comprising a drive shaft (19) and at least one actuatable clutch (22) for selective driving of a third or fourth gear element (24 or 26), these elements being in drive connection with either the first or second gear element (38 or 40), respectively, characterized in that the four gear elements (24, 26, 38, 40) are all disposed on one side of the imbalance system (12) and shielded by a cover (50).

2. Vibration machine according to claim 1, characterized in that the unbalanced masses (46, 48) are adjacent to each other in axial direction and are disposable in at least two angular positions relative to each other to achieve different total imbalances, the unbalanced mass not coupled with the drive shaft being taken along by the other unbalanced mass in at least one of said angular positions, and that for the angular position, in which the unbalanced masses (46,48) have the smaller angular space between them, a stop (46a) taking along the second unbalanced mass (48) rotates together with the first, driven unbalanced mass (46), this stop being disposed such that the first unbalanced mass (46) is ahead of the second unbalanced mass (48).

3. Vibration machine according to claim 2, the unbalanced masses of which have different imbalance momentums, characterized in that the first unbalanced mass (46) has the greater imbalance momentum.

4. Vibration machine according to claims 2 or 3, characterized in that a stop (46b) taking along the first unbalanced mass (46) is provided for the angular position, in which the unbalanced masses have the greater angular distance between them.

5. Vibration machine according to any or several of the preceding claims, characterized in that the clutch for the third and fourth gear elements (24, 26 or 116a, 118a or 116a', 118a') has a clutch cylinder (16b, 18b or 116b', 118b') for each of said gear elements, these cylinders being disposed next to each other in axial direction and having only one single, actuatable flyweight clutch element (130 or 130') associated with them, this flyweight clutch element being secured to the drive shaft (19 or 110) such that they do not rotate relative to each other, and that for changing the clutch clutch element (130; 130') and clutch cylinders (116b, 118b; 116b', 118b') are movable relative to each other in axial direction such that the clutch element is selectively disposable inside one of the clutch cylinders associated with it.

6. Vibration machine according to claim 5, characterized in that the clutch cylinders (116b, 118b) are each secured to a gear element (116a, 118a) such that they do not rotate relative to each other, are disposed between these elements in axial direction and rotatably mounted together with these elements on the drive shaft (110).

7. Vibration machine according to claims 5 and 6, characterized in that an actuating element (120) penetrating the drive shaft (110) in axial direction is provided for the clutch element (130) displaceable along the drive shaft.

8. Vibration machine according to claim 6, characterized in that the clutch cylinders (116b', 118b') are not rotatable relative to the gear element (116a_', 118a') associated with each cylinder, are displaceable in axial direction and disposable alternatingly over the clutch element (130').

9. Vibration machine according to claim 8, characterized in that an actuating element (124') is rotatably mounted on the clutch cylinders (116b', 118b') and rigidly connected with these in axial direction.

Images