EP3918134B1 - Cutting wheel assembly for a slurry wall cutter - Google Patents

Description

The present invention generally relates to trench cutters for milling trench walls in special civil engineering. The invention relates in particular to the cutting wheel arrangement for such a trench cutter with a cutter hub that can be driven in rotation and a cutter wheel that can be detachably fastened to the cutter hub in a rotationally fixed manner.

Such trench cutters show, for example, the writings EP 19 75 323 A1 , EP 0 841 467 A1 and EP 25 97 205 A1 .

Diaphragm wall cutters are generally used in special foundation engineering in order to mill slits in the ground, rock or subsoil, which are filled with a suspension containing, for example, concrete to form a diaphragm wall. Diaphragm walls are generally wall constructions in the subsoil made of, for example, concrete, reinforced concrete and the like. In order to produce such a diaphragm wall, a trench wall cutter is used to cut a substantially vertical slot open at the top, with the cutting tool being lowered into the ground from above and being guided by a carrier device such as a crawler-type crawler crane that is supported on the ground and is preferably mobile. The trench wall cutter usually includes an elongated, upright cutting frame that is suspended from the carrier device so that it can be moved vertically and usually carries a plurality of cutting wheels at its lower end, which can be driven in opposite directions about respective axes. The drive for rotationally driving the cutting wheels can also be mounted on a lower section of the cutting frame and include, for example, one or more hydraulic motors that can drive the cutting wheels, for example via a chain drive and/or one or more gear stages.

The cutting wheels of such a trench cutter have to be changed regularly and relatively frequently. On the one hand, the milling tools, which are arranged circumferentially on the milling wheels, are subject to heavy wear. In order not to have to change the many cutting tools individually, the entire cutting wheel is usually dismantled and replaced by another cutting wheel with fresh cutting tools. On the other hand, different milling wheels, optimized in each case, are also used for different soil conditions. Since the soil condition can vary depending on the milling depth, the milling wheels are often changed when milling a single slot if the soil condition changes with increasing milling depth. Furthermore, different cutting wheels are also used for different trench widths and depths, so that overall the cutting wheels of a trench wall cutter have to be changed quite frequently.

In order to lose as little time as possible on a construction site for changing the cutting wheels and to have as little downtime as possible for the machine, it is desirable to make the changing process as simple as possible. The cutting wheels of a trench wall cutter are usually clamped to the cutter hub with a friction fit. In order to be able to transmit the very high forces and torques between the milling wheel and the milling cutter hub during milling operations, a large number of screws, for example 48 bolts per milling wheel, are usually used, by means of which the respective milling wheel is frictionally clamped against the milling cutter hub. In order to achieve uniform tightening, all screw bolts must be tightened with the same torque, for example using a torque wrench, so that the sum of the pretensioning forces of the screws clamps the milling wheel to the milling cutter hub and holds it in place with friction. The disadvantage here, however, is that when changing the cutting wheel, all the screws are loosened and then have to be reassembled with even torque tightening, which is very complex and time-consuming.

In order to reduce the amount of time required to change the cutting wheel, it has already been proposed to provide a type of bayonet catch between the cutter hub and the cutting wheel, cf. EP 25 97 205 B1 . Slot-shaped recesses are provided on the milling cutter hub distributed around the circumference, which are open on one side, so that projections provided on the milling wheel, suitably designed, can be inserted into the pocket-shaped recesses and locked by turning. The projections and the pocket-shaped recesses are each wedge-shaped, so that they jam against one another when the cutting wheel is rotated relative to the hub. However, with this bayonet-type connection, the stated clamping and power transmission can only be achieved in one direction of rotation. If the milling wheels are rotated backwards, the bayonet-type clamping connection will loosen unintentionally.

In order to avoid this problem of the direction of rotation, it has already been considered to design the milling cutter hub in the manner of a hexagon and to provide a complementary, likewise hexagonal recess on the milling wheel, which can be pushed onto the hexagonal contour of the hub. However, such a polygonal connection usually has to be designed with play in order to enable simple assembly and disassembly, which, however, then leads to corresponding wear during operation. In addition, forces can only be transmitted in the radial direction, but not in the axial direction, so that additional clamping or tensioning means must be provided in order to be able to dissipate the axial forces that also occur during operation.

The present invention is therefore based on the object of creating an improved trench wall cutter and an improved cutting wheel arrangement which avoid the disadvantages of the prior art and develop the latter in an advantageous manner. In particular, an easy and quick to assemble and disassemble Milling wheel attachment can be created that can transmit the forces and moments occurring during operation with as little wear as possible.

According to the invention, the stated object is achieved by a cutting wheel arrangement according to claim 1 and a trench wall cutter according to claim 14. Preferred developments of the invention are the subject matter of the dependent claims.

It is therefore proposed to clamp the milling wheel and the milling cutter hub against one another at the front and to fix them in a form-fitting manner in relation to one another in order not to transmit the high operating forces, or at least not only to transmit them by friction. According to the invention, the end faces of the milling wheel and the milling cutter hub that can be joined together are provided with end teeth that mesh with one another in a torque-proof manner. The cutter hub and the cutter wheel are held in a non-rotatable form-fitting manner relative to one another by the interlocking pair of end teeth. At the same time, the end faces that are seated next to one another can also transmit axial forces, so that the cutting wheel is held in place so that it cannot tilt. Since the operating forces and moments are transmitted in a form-fitting manner through the toothing engagement, the cutting wheel can be secured to the cutting hub in a relatively simple manner, for example by a few screws, so that the time required for disassembly and assembly can be significantly reduced.

In particular, the intermeshing end teeth on the end faces of the milling wheel and milling cutter hub can form a form-fitting connection that is free of play, which prevents micro-movements due to its lack of play and thus drastically reduces wear. At the same time, the milling wheel and milling cutter hub can be assembled or disassembled by means of a one-dimensional movement, in particular by simply pushing one on top of the other from the front side, without an additional twisting or threading movement being necessary, as is the case with a bayonet lock.

In principle, however, it would also be possible to design the spur gear stage with a little play. In a development of the invention, a centering or centering device can be provided, for example attached to the hub pot to transmit additional radial forces and to relieve the spur gearing.

In order to secure the milling hub and the milling wheel to one another in the axial direction or at the front or to brace them against one another, axially effective clamping means can be provided between the milling wheel and the milling hub, which pull and/or press the milling hub against the milling hub in the direction of the axis of rotation. Such axial clamping means can fundamentally be designed in different ways, for example having a central lock, for example in the form of a central screw lock. Alternatively or additionally, a few screw bolts can be distributed over the circumference in order to tension the cutting wheel against the cutting hub and/or to clamp it tightly. Said screw bolts can advantageously be distributed along a pitch circle passing through the spur gearing. In particular, the screw bolts can be provided in the area of intermeshing face toothing sections in order to ensure that the toothings mesh with one another with an exact fit, even under operating forces.

The intermeshing spur gearing stage can fundamentally be designed differently, for example, have spur gearing running around in the form of a closed ring on each end face. In an advantageous development of the invention, however, the spur gears on the faces of the cutting hub and the cutting wheel can advantageously each have a plurality of spaced groups of teeth, which can be distributed over the circumference and spaced from each other. For example, groups of teeth and tooth-free surfaces can alternate when viewed in the circumferential direction.

Advantageously, at least three such groups of teeth and at most ten such groups of teeth can be provided, with four to eight or in particular six groups of teeth being distributed over the circumference in a further development of the invention. Alternatively, only one group of teeth can be provided, which can be distributed completely over the circumference.

The teeth of the toothing can be contoured and/or profiled differently. In order to be able to equally transmit torques and also radial and axial forces, it can be advantageous if the teeth within each group of teeth are arranged or aligned parallel to one another, but the different groups of teeth are arranged rotated relative to one another with regard to the orientation of their teeth.

In an advantageous development of the invention, it can be provided that the teeth each have a straight tooth flank profile and the teeth of each tooth group are arranged parallel to one another. Looking at the tip of each tooth, the ridge forming the tip may have a straight course. In principle, it would be conceivable for the teeth to have a curved course. Advantageously, however, the teeth can each have a straight course when considering their peaks or ridges and the valleys lying between the teeth.

In particular, the respective groups of teeth can have a tooth that extends in the radial direction, while the other teeth can extend parallel thereto and thus offset transversely to the radial direction. In particular, a middle tooth of a respective group of teeth can run in the radial direction and be flanked on the right and left by teeth aligned parallel thereto.

The groups of teeth mentioned can have a different number of teeth, for example between three and ten teeth, in particular about six to eight teeth, it being possible for all groups of teeth to have the same number of teeth.

In a further development of the invention, the groups of teeth can also be arranged or configured asymmetrically overall, for example by having one group of teeth have a smaller number of teeth than the other groups of teeth. In this way it can be ensured that the cutting wheel opens in only one predetermined rotational position the milling hub fits. Alternatively or additionally, a predetermined rotary mounting position of the cutting wheel can also be achieved by a corresponding arrangement of the bolts, for example by an uneven distribution in the circumferential direction, for example by an additional bolt with an otherwise uniform pitch pattern.

Such a clear definition of the rotational mounting position of the cutting wheel on the associated cutting hub can ensure the desired rotational position relative to one another, especially when there are several cutting wheels, in order to ensure synchronous rotation or meshing of the cutting tools. In particular, the cutting wheels can be aligned with one another in such a way that cutting tools projecting on the peripheral side do not collide with one another, even if the cutting wheels are arranged very close to one another.

The teeth of the spur gearing step can fundamentally be profiled differently, wherein the teeth can advantageously be formed symmetrically to a sectional plane parallel to the axis of rotation through a respective tooth profile, viewed in cross section, in order to be able to transmit forces equally in both directions of rotation.

In particular, viewed in cross section, the teeth can each be contoured in the shape of a truncated wedge and/or have straight or even tooth flanks. Such wedge-shaped teeth can be contoured, for example, at a wedge angle of 2 times 10° to 2 times 40° or 2 times 15° to 2 times 30° or in particular about 2 times 20°. With a wedge angle in the range of 2 times 15° to 2 times 25°, on the one hand play-free meshing can be ensured and on the other hand excessive jamming during tightening can be prevented.

The teeth can be flattened at their pointed levels. The valleys between two teeth or the respective tooth bases can advantageously be contoured in cross-section in order to avoid stress peaks in the tooth base.

Fig. 1:

eine schematische, perspektivische Darstellung einer Schlitzwandfräse nach einer vorteilhaften Ausbildung der Erfindung,

Fig. 2:

eine perspektivische, teilweise geschnittene Darstellung eines Fräsrads und einer Fräsernabe der Schlitzwandfräse aus der vorhergehenden Figur, wobei die Fräsernabe und das Fräsrad im aneinander montierten Zustand gezeigt sind,

Fig. 3:

eine perspektivische, teilweise geschnittene Darstellung des Fräsrads und der Fräsernabe ähnlich Figur 2, wobei das Fräsrad und die Fräsernabe im voneinander demontierten Zustand gezeigt sind,

Fig. 4:

eine Draufsicht auf die Stirnseiten des Fräsrads und der Fräsernabe aus den vorhergehenden Figuren, welche Stirnseiten mit jeweils einer Stirnverzahnung versehen sind, und

Fig. 5:

eine ausschnittsweise Schnittansicht entlang der Linie A-A in Figur 4, die die ineinandergreifenden Stirnverzahnungen von Fräsernabe und Fräsrad zeigt.

The invention is explained in more detail below using a preferred exemplary embodiment and associated drawings. In the drawings show:

Figure 1:

a schematic perspective view of a trench wall cutter according to an advantageous embodiment of the invention,

Figure 2:

a perspective, partially sectioned representation of a cutting wheel and a cutting hub of the trench wall cutter from the previous figure, the cutting hub and the cutting wheel being shown in the assembled state,

Figure 3:

a perspective, partially sectioned representation of the milling wheel and the milling cutter hub similar figure 2 , with the cutter wheel and cutter hub shown disassembled from each other,

Figure 4:

a plan view of the end faces of the milling wheel and the milling cutter hub from the previous figures, which end faces are each provided with a face toothing, and

Figure 5:

a partial sectional view along the line AA in figure 4 , showing the intermeshing face gears of the cutter hub and cutter wheel.

How figure 1 shows, the trench wall cutter 1 can have an elongate, upright arranged cutter frame 2, which can be designed as a frame girder and/or can comprise two laterally arranged longitudinal guide profiles. At a lower end section, the milling frame 2 can have at least two milling wheels 3, which are arranged next to one another and can be driven in rotation about respective axes of rotation, in which case the axes of rotation of the milling wheels 3 can extend parallel to one another, in particular perpendicularly to the flat side of the milling frame 2.

The two cutting wheels 3 can be driven in opposite directions to one another. A milling drive 4 can be arranged on a lower end section of the milling frame 2 above the milling wheels 3 and can comprise, for example, one or more hydraulic motors which can drive the milling wheels 3 via one or more gear stages.

How figure 1 shows, the milling frame 2 with the milling wheels 3 can be held by a carrier device 5 such that it can be raised and lowered or suspended therefrom. Said carrier device 5 stands on the ground in which the respective slot is to be milled and can advantageously be designed to be movable. In particular, a cable excavator with a chassis, for example a tracked chassis 6 , can be provided as the carrier device 5 , with the milling frame 2 being able to be raised and lowered by a boom 7 of the carrier device 5 .

As the Figures 2 to 5 show, each cutting wheel 3 is attached to a cutter hub 8 which is rotatably mounted on the cutter frame 2 and can be driven by the cutter drive 4 . The cutter hub 8 can be formed by the driven element of the cutter drive 4 or by an intermediate gear stage. In particular, said gear stage can be designed as a planetary gear, wherein the cutter hub 8 can be formed, for example, by a planet carrier of the planetary gear.

In particular, the milling cutter hub 8 can have a rotatably mounted hub pot 9 which can have, for example, a planar end face 10 against which the milling wheel 3 can be clamped.

The cutting wheel 3 can be constructed in the manner of a rim and, independently of this, have a peripheral wall 11 on the outside of which one or more rows of cutting tools 12 can be arranged, for example in the form of cutting tools. Said peripheral wall 11 is rigidly connected to a fastening flange 13 which can be designed as a disc or ring and, independently of this, has an end face 14 which can be placed against the end face 10 of the cutter hub 8 is. Said fastening flange 13 can extend approximately in a plane perpendicular to the axis of rotation and have a flat end face 14 which faces the cutter hub 8 .

Advantageously, said fastening flange 13 is detachably fastened to the rest of the body of the cutter wheel 3 in order to be able to be replaced when worn. For example, the fastening flange 13 can be fastened to the body of the cutting wheel 3 by means of several screws 15 .

As the Figures 3 , 4 and 5 show, the end faces 10 and 14 of the milling cutter hub 8 and the milling wheel 3 that can be joined together are each provided with end teeth 16, 17, which are designed and arranged to fit one another in a form-fitting manner, so that the two end teeth 16 and 17 mesh with one another when the end faces 10 and 14 of the cutter hub 8 and the cutter wheel 3 are placed one on top of the other. The spur gears 16 and 17 are designed in such a way that they come into engagement with one another parallel to the axis of rotation by simply pushing the milling wheel 3 and milling cutter hub 8 onto one another axially. The two face gears 16 and 17 sit on top of each other so that they mesh, like this figure 5 shows, the cutting wheel 3 is positively and non-rotatably fixed to the cutter hub 8 .

The cutting wheel 3 can be clamped axially against the cutter hub 8 by axial clamping means 18, which can advantageously include a plurality of bolts 19, in order to secure the cutting wheel 3 on the cutter hub 8 and to keep the face gears 16 and 17 positively engaged. How figure 3 shows, several bolts 19 can be arranged distributed in the circumferential direction, in particular in the region of the spur gears 16 and 17, in order to fix the spur gears 16 and 17 uniformly in the engaged position.

How figure 4 shows, the spur gears 16 and 17 can each have several--6 in the illustrated embodiment--tooth groups 20, which are spaced apart from one another in the circumferential direction and distributed evenly, optionally also unevenly can be distributed. In particular, the groups of teeth 20 can be arranged on a common pitch circle and each be separated from one another by tooth-free surfaces 21 .

How figure 4 shows, each tooth group 20 can have a plurality of teeth 22, each of which can have straight tooth flanks, wherein all tooth flanks of a tooth group can be arranged parallel to one another, while the tooth groups 20 can be twisted relative to one another or aligned in different directions. In particular, a respective middle tooth of a respective group of teeth 20 can extend in the radial direction with respect to the axis of rotation and be flanked on the right and left by teeth arranged parallel thereto.

How figure 5 shows, the teeth 22 of the spur gears 16 and 17 viewed in cross-section can each be contoured in the shape of a truncated wedge, the tooth flanks of the teeth 22 in the shape of a truncated wedge being able to extend at a wedge angle of, for example, 2 times 20°.

In the area of the tooth tips, the teeth 22 can be flat or truncated. Irrespective of this, the valleys between the teeth 22 or the tooth root areas can be rounded off, cf. figure 5 .

Claims (15)

1. Cutting wheel assembly for a trench wall cutter (1) having a rotatingly drivable cutter hub (8) and a cutting wheel (3) that is releasably fastened to the cutter hub (8) in a rotationally fixed manner, characterized in that end faces (10, 14) of the cutter hub (8) and of the cutting wheel (3) that can be placed at one another are provided with shape matched end toothed arrangements (16, 17) that can be placed at one another at the end face that rotationally fixedly engage into one another.
2. Cutting wheel assembly in accordance with the preceding claim, wherein the end faces (10, 14) have tooth-free surfaces (21) between the end toothed arrangements (16, 17).
3. Cutting wheel assembly in accordance with one of the preceding claims, wherein axial clamping means (18) are provided for the axial tensioning against one another of the end faces (10, 14) of the cutting wheel (3) and of the cutter hub (8).
4. Cutting wheel assembly in accordance with one of the preceding claims, wherein the axial clamping means (18) comprise screws and/or threaded bolts (19) that are arranged distributed along a partial circle passing through the end toothed arrangements (16, 17).
5. Cutting wheel assembly in accordance with one of the preceding claims, wherein the end toothed arrangements (16, 17) each comprise a plurality of tooth groups (20) arranged distributed in the circumferential direction spaced apart from one another, wherein each tooth group (20) comprises a plurality of teeth (22), wherein the teeth (22) within a tooth group (20) are aligned in parallel with one another and the tooth groups (20) are arranged rotated relative to one another such that the teeth (22) of different tooth groups extend inclined at an acute angle with respect to one another.
6. Cutting wheel assembly in accordance with one of the preceding claims, wherein the end toothed arrangements (16, 17) comprise straight teeth (22) whose tooth tips define a straight extent.
7. Cutting wheel assembly in accordance with one of the preceding claims, wherein a middle tooth (22) of at least one tooth group (20) is arranged radially to the axis of rotation of the cutter hub (8) and of the cutting wheel (3) and all the other teeth (22) of the same tooth group are arranged in parallel therewith.
8. Cutting wheel assembly in accordance with one of the preceding claims, wherein the teeth (22) of the end toothed arrangements (16, 17) are each frustoconically contoured, viewed in cross-section.
9. Cutting wheel assembly in accordance with one of the preceding claims, wherein the teeth (22) of the end toothed arrangements (16, 17) have planar tooth flanks and/or have straight tooth flanks in cross-section that are set at a wedge angle in the range of 2 times 50°, 2 times 15°, or 2 times 40° to 2 times 25°.
10. Cutting wheel assembly in accordance with one of the preceding claims, wherein the end toothed arrangement (16) of the cutting wheel (3) is provided at a fastening flange (13) that is releasably fastened to a cutting wheel body, which cutting wheel body supports cutting tools, and/or the end toothed arrangement (17) of the cutter hub (8) is provided at a hub plate or at a hub flange that is releasably fastened to a hub pot (9).
11. Cutting wheel assembly in accordance with one of the preceding claims, wherein the end toothed arrangements (16, 17) are configured such that the cutting wheel (3) is fastenable at the cutting hub (8) in a maximum of six different rotary positions, or a maximum of two different rotary positions, or a maximum of only one rotary position relative to the cutting hub (8)
12. Cutting wheel assembly in accordance with one of the preceding claims, wherein the end toothed arrangements (16, 17) are formed as transmitting force and/or torque equally in two opposite directions of rotation.
13. Cutting wheel assembly in accordance with one of the preceding claims, wherein the cutter hub (8) is formed by the output part of a transmission stage, in particular in the form of a hub pot (9), by which the cutting wheel (3) is connected to a cutting drive (4) in a torque transmitting manner, wherein the transmission stage comprises a planetary gear and the cutter hub (8) is formed by the planetary carrier of the planetary gear.
14. Trench wall cutter having a cutting wheel assembly that is configured in accordance with one of the preceding claims.
15. Trench wall cutter in accordance with the preceding claim, wherein the cutting wheel (3) and the cutter hub (8) are supported at an elongate upright cutting frame (2) that supports a cutting drive (4) and is suspended at a travelable support unit (5) standing on the ground.

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