EP3904603B1 - Trench wall cutter - Google Patents

Description

The invention relates to a trench wall cutter with at least one pair of cutting wheels, at least one bearing plate on which the cutting wheels of a pair are rotatably arranged on both sides of the bearing plate, a base frame on the underside of which at least one bearing plate is attached, and a cutting wheel drive for driving the Milling wheels via a gear lubricated with gear oil in the end shield, according to the preamble of claim 1.

A generic trench cutter is from EP 1 637 794 B1 known. In this trench wall cutter, an oil circuit is arranged between the cutting wheels, which are arranged at a lower end of the bearing plate, and a frame housing with the cutting wheel drive. Oil is conveyed from the auger wheels up through the auger blade to the auger wheel drive in the housing by the drive shaft. An oil return follows via a return line in the end shield. During operation, the end shield is covered on both sides by the milling wheels and the support suspension can hardly flow around it.

Another generic trench cutter is from EP 1 580 327 B1 known. In this trench wall cutter, a drive torque from an individual drive motor is transmitted via a central drive shaft in a bearing plate to a sun wheel, from which the torque is distributed to the individual pairs of cutting wheels.

From the post-published WO 2020/114656 A1 (& EP 3 701 091 A1 ) a hydraulic circuit diagram of a trench cutter is known. Optionally, a heat exchanger in an oil return line to the auger gearbox is suggested. However, this disclosure does not give any information about the arrangement of the heat exchanger.

The EP 2 924 174 A1 , EP 3 467 209 A1 and JP-H07 138 979 A1 show well-known trench cutters with their mechanical design of the cutter wheel gears. In some cases, the hydraulic connection of the various components is also shown.

The invention is based on the object of specifying a trench wall cutter in which a particularly high cutting capacity is ensured with reliable lubrication of a gear arrangement for driving the cutting wheels.

The object is achieved according to the invention by a trench wall cutter with the features of claim 1. Preferred embodiments of the invention are given in the dependent claims.

The trench cutter according to the invention is characterized in that at least one heat exchanger is arranged above the bearing plate and that an oil circuit is designed to cool the transmission oil, to which at least one heat exchanger is connected above the bearing plate.

A basic idea of the invention is based on the knowledge that the gear arrangement in a trench wall cutter is exposed to considerable forces, particularly when cutting through harder soil or rock layers, which can result in the gear oil being heated to a great extent. Excessive heating of the gear oil can cause a lubricating film to break off on contacting gears and lead to increased wear on the gears and bearings. This can limit the milling performance and shorten the service life of the gearbox.

In order to counteract this problem, it is provided according to the invention to provide an oil circuit with at least one heat exchanger through which the transmission oil is conducted. The heat exchanger is located away from the milling point and the end shield with the gear, namely above the end shield. The oil circuit can be formed by means of oil lines.

In this way, according to the invention, targeted cooling takes place at an exposed area in the fluid-filled milling slot of the housing above the milling wheels and above the end shield. This area on or even above the base frame offers the possibility of a very large wall construction of a preferably plate-shaped heat exchanger. Several heat exchangers can also be arranged. In this way, even if the transmission oil in the oil circuit heats up considerably, it can be cooled down to a desired operating temperature, so that the oil has a desired viscosity for forming a stable lubricating film during operation. In this way, particularly high milling performance can be achieved.

A preferred embodiment of the invention is that the heat exchanger is designed as a plate which is detachably attached to the base frame or to a holding device above the base frame. The heat exchanger can therefore be attached to struts of the base frame or to the holding device on which the base frame is suspended. The holding device can be a guide rod, a holding cable and/or feed lines.

According to a development of the invention, it is advantageous that the milling drive is arranged in a housing and that the heat exchanger is formed in or on an outer wall of the housing. In the case of a compact milling machine, such as a CSM milling machine, without guide plates, the base frame is essentially formed by the housing of the milling wheel drive. In this case, the heat exchanger can be designed in a compact manner on the housing.

It is advantageous that the outer wall of the housing is designed as a cooling wall, with at least one groove being introduced on an inside of the cooling wall to form an oil duct, in which a hose-shaped or tubular line is arranged. The at least one outer wall of the housing can be designed as a cooling wall in which at least one oil duct is arranged, oil for cooling being able to be conducted through the at least one oil duct in the outer wall of the housing.

A preferred embodiment of the invention consists, in particular, in that the oil duct is designed in the shape of a loop, preferably in a meandering shape, in the outer wall of the housing. As a result, the oil in the cooling wall can be cooled particularly strongly and quickly.

The heat exchanger is designed in particular as a separate plate which is detachably fastened. This means that existing trench cutters can also be retrofitted or converted. The plate can be in two parts, with a cover plate covering an oil duct in a base plate. The cooling plate can also be applied, in particular screwed, to a smooth-surfaced housing wall.

A particularly expedient embodiment is achieved according to a further development of the invention in that at least one groove is introduced to form the oil duct on an inside of the cooling wall, in which a hose or tubular line is arranged. The groove can accordingly run in a loop or meander shape. In principle, it is also possible to form the groove directly as an oil duct by means of a corresponding seal. The use of a hose-like or tubular line, which can be made of metal, preferably high-grade steel, or plastic, leads to a particularly simple design with a high degree of tightness.

Particularly good cooling can be achieved with the trench wall cutter according to the invention in that the plate-shaped heat exchanger comprises a metal with high thermal conductivity, in particular aluminum or an aluminum alloy. In particular, a metal is provided which has a higher thermal conductivity than steel. A particularly strong cooling effect can be achieved in this way. In a test, a cooling capacity of approx. 3.2 kW was achieved when using a steel plate, while a cooling capacity of approx. 11.2 kW was achieved when using an aluminum plate.

A further preferred embodiment of the invention consists in that at least one pumping device is provided, through which the oil in the oil circuit can be pumped. The pump device can be an electrically or hydraulically driven pump, preferably with a variable delivery volume. In particular, the pump device can be driven by a control device, which changes the delivery flow through the oil duct depending on the current oil temperature, which can be detected, for example, by a temperature sensor. Heat can be dissipated as required in this way.

A particularly simple configuration of a trench wall cutter according to the invention is achieved in that the pump device comprises a shaft driven by the cutter drive, which shaft is provided on its outside with at least one conveying helix to form a worm pump. The shaft of the pumping device can be driven in rotation by the cutting wheel drive via a separate drive train.

According to one embodiment variant of the invention, it is particularly advantageous that the shaft is the drive shaft, which extends from the cutting wheel drive through the bearing plate to the cutting wheels. The drive shaft runs essentially vertically and is provided on its outside with a conveyor helix, in particular grooves, through which oil in the shaft channel is conveyed upwards along the shaft by the cutting wheels. As a result, oil can be conveyed from the cutting wheels in the direction of the cutting wheel drive without a great deal of design effort. The cutting wheel drive preferably includes one or more hydraulic motors.

For targeted control of the oil flow, it can be advantageous according to a development of the invention that a control valve is provided which blocks an oil line channel of the oil circuit at a first low temperature and releases the oil line channel at a second, higher temperature. The control valve can be actuated depending on the oil temperature by the control already mentioned above. In particular when starting the cutting wheel drive with a low temperature of the gear oil, the oil duct will be blocked so that the gear oil is heated to the operating temperature as quickly as possible. When a second, higher temperature is exceeded, the control valve can then open and release the oil line channel. Thus, oil can flow through the oil duct into the heat exchanger, so that a corresponding cooling can be achieved.

In principle, the at least one cooling wall can be arranged at any point on the outside of the housing or the milling frame. According to one embodiment of the invention, it is particularly advantageous that at least two cooling walls are provided, which are arranged on the longitudinal sides of the housing. As a result, sufficient cooling can also take place in the event of particularly strong heating. The housing can be designed as a lattice frame, on or in which one or more cooling plates are arranged.

Fig. 1

eine Vorderansicht einer erfindungsgemäßen Schlitzwandfräse;

Fig. 2

eine schematische teilgeschnittene Darstellung zum Verlauf eines Ölleitungskanals bei der Schlitzwandfräse von Fig. 1;

Fig. 3

eine vergrößerte Teilquerschnittsansicht durch eine Kühlwand für die Erfindung; und

Fig. 4

eine schematische Darstellung eines Teils des Ölkreislaufs bei einer erfindungsgemäßen Schlitzwandfräse.

The invention is further described below with reference to a preferred exemplary embodiment, which is illustrated schematically in the accompanying drawings. In the drawings show:

1

a front view of a trench cutter according to the invention;

2

a schematic, partially sectioned representation of the course of an oil duct in the trench wall cutter from 1 ;

3

Figure 3 is an enlarged partial cross-sectional view through a cooling wall for the invention; and

4

a schematic representation of part of the oil circuit in a trench cutter according to the invention.

A trench wall cutter 10 according to the invention 1 has a base frame 30 with a housing 31 on the underside of which two plate-shaped end shields 14 are attached. A cutting wheel 12 with a multiplicity of cutting teeth 13 for cutting off soil material are rotatably mounted on both sides of the bearing plates 14 . Furthermore, a wedge-shaped suspension feed 16 can be arranged between the two pairs of cutting wheels 12 on the underside of the base frame 30 . During the milling operation, a support and milling suspension can be introduced into the milling slot formed via the suspension feed 16 . The supplied suspension can be provided with a binder, so-called soil cement can be formed by mixing it with the milled off soil fragments, which can harden in the milled trench to form a trench wall segment.

Plate-shaped adjusting and guiding elements 18 are provided along the narrow sides of the base frame 30 . These can lie against the wall of the cut trench during cutting, with the trench wall cutter 10 being able to be guided and adjusted in the cut cut by a corresponding adjustment of the adjusting elements 18 . On an upper side of the housing 31 of the base frame 30, a cable suspension or a guide rod for holding and vertically adjusting the trench wall cutter 10 in the cut trench is provided in a known manner.

On one or preferably both longitudinal sides of the box-shaped base frame 30, a plate-shaped outer wall 32 is provided to form a heat exchanger 60, which as a in the figures 2 and 3 cooling wall 34 shown in detail is formed. The cooling wall 34 can form a wall of the housing 31 .

The heat exchanger 60 with the cooling wall 34 is according to 3 designed as a flat plate, preferably made of stainless steel. The cooling wall 34 has an inner side 35 directed towards the housing 31 and an opposite outer side 37 which forms an outside of the housing 31 in the assembled state. A groove 38 is milled along the inside 35 of the cooling wall 34, which according to the representation of FIG 2 is designed meandering. In this loop-shaped groove 38 is a line 40 made of a metal tube, such as copper, is inserted. The line 40 thus forms the oil line channel 36 in the cooling wall 34. The line 40 has connections 42 at its ends, with which the heat exchanger 60 can be connected to an oil circuit 50, which is partially shown schematically in FIG 4 is shown.

According to the highly schematized representation of 4 a partially indicated cutting wheel drive 20 is shown with numerous bearings. From the cutting wheel drive 20, a drive shaft 22 (only partially shown) for each bearing plate 14 extends downwards to the cutting wheels 12 lying below. The drive shaft 22 is provided on its outside with conveying grooves, not shown, which can convey gear oil from the area of the cutting wheels 12 upwards in the direction of the cutting wheel drive 20 . The oil flows through the bearings and gear wheel arrangement of the only schematically indicated cutting wheel drive 20. The cutting wheel drive 20 can preferably include at least one hydraulic motor and an output and distribution gear.

At least part of the transmission oil is conducted via a pump device (not shown) via a feed 44 of an oil circuit 50 to an upper connection of the heat exchanger 60 with a meandering oil duct 36 in the cooling wall 34 . The heated oil can flow through the meandering oil duct 36 in the cooling wall 34 from top to bottom and in the process emit heat to the cooling wall 34 with its free outer side facing the suspension-filled slot. The oil duct 36 can be formed in the cooling wall 34 with a slight gradient of, for example, approximately 15°, so that an oil flow can be set without a great deal of pressure being applied.

The cooled transmission oil is routed back to the cutting wheel drive 20 via a return line 46 of the oil circuit 50 . Via a return line 52, the transmission oil can be routed downwards from the cutting wheel drive 20 to the cutting wheels with the distribution gear. The oil, which has been heated up again in particular in the area of the distribution gear, can then be pumped upwards again via the conveying effect of the drive shaft 22 to the cutting wheel drive 20 and the heat exchanger 60 above the end shield 14 . A control valve 28 is provided on the supply line 44 or, as shown, on the return line 46 in order to control the flow of oil through the oil line channel 36 . At the intended temperatures, this can control the oil flow through the oil duct 36 and block or open it altogether. The control takes place depending on temperature sensors, not shown, which measure a temperature of the transmission oil at one or more points in the oil circuit 50 . The cooling circuit can also have a branch for pressure equalization of the transmission arrangement.

Claims (10)

1. Trench cutter, comprising

   - at least one pair of cutting wheels (12),

   - at least one bearing plate (14) on which the cutting wheels (12) of a pair are rotatably arranged on the two sides of the bearing plate (14),

   - a base frame (30) on the underside of which the at least one bearing plate (14) is attached, and

   - a cutting wheel drive (20) for driving the cutting wheels (12) via a transmission lubricated with transmission oil in the bearing plate (14),

   characterized

   - in that at least one heat exchanger (60) is arranged above the bearing plate (14), and

   - in that for cooling the transmission oil, an oil circuit (50) is formed to which the at least one heat exchanger (60) is connected above the bearing plate (14).
2. Trench cutter according to claim 1,
   characterized
   in that the heat exchanger (60) is designed as a panel which is fastened in a releasable manner on the base frame (30) or on a holding device above the base frame (30).
3. Trench cutter according to claim 1 or 2,
   characterized

   in that the cutting drive (20) is arranged in a housing (31), and

   in that the heat exchanger (60) is designed in or on an outer wall (32) of the housing (30).
4. Trench cutter according to claim 3,
   characterized
   in that the outer wall (32) of the housing (31) is designed as a cooling wall (34), wherein to create an oil conducting channel (36) on an inner side of the cooling wall (34), at least one groove (38) is introduced in which a hose-shaped or tube-shaped line (40) is arranged.
5. Trench cutter according to one of claims 1 to 4,
   characterized
   in that the panel-shaped heat exchanger (60) comprises a metal with high thermal conductivity, more particularly aluminium or an aluminium alloy.
6. Trench cutter according to one of claims 1 to 5,
   characterized
   in that at least one pump device is provided via which the oil can be conveyed in the oil circuit (50).
7. Trench cutter according to claim 6,
   characterized
   in that the pump device comprises a shaft driven by the cutting wheel drive (20), which shaft is provided with at least one conveying helix on its outer side.
8. Trench cutter according to claim 7,
   characterized
   in that the shaft is the drive shaft (22) which extends from the cutting wheel drive (20) through the bearing plate (14) to the cutting wheels (12).
9. Trench cutter according to one of claims 1 to 8,
   characterized
   in that a control valve (28) is provided which blocks an oil conveying channel (36) of the oil circuit (50) to the heat exchanger (60) at a first low temperature and releases the oil conveying channel (36) at a second higher temperature.
10. Trench cutter according to one of claims 1 to 9,
    characterized
    in that at least two cooling walls (34) are provided which are arranged on the long sides of the housing (30).

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