EP1975323B1 - Cutting head for a soil-cutting machine with rotary cutters - Google Patents

Abstract

The head has a drill motor including hydraulic motors (44, 46) that are provided with stators (44a, 46a) and rotors (44b, 46b), and a common shaft (50) extending along a common axis (XX'). Transmission assemblies connect ends (50b, 50c) of the shaft to grinder drums (22, 24), where the assemblies are formed of rims (52, 54), and covers (64, 66). Mechanical systems (60, 62) directly integrate the rotors of the hydraulic motors with the assemblies corresponding to the drums closer to the hydraulic motors.

Description

The present invention relates to a cutting head for a ground milling machine with rotary milling cutters.

A first type of such a machine is used to make in the ground trenches of relatively large depth, up to 100 meters, and relatively small width relative to said depth, the width typically being between 500 mm and 1500 mm. One of the interests of these machines is to allow the realization of such trenches of significant depth that meet stringent verticality criteria. The entire trench is obtained by successive digging of juxtaposed panels.

In general, these cutting machines are constituted by a frame of relatively large height which provides mechanical guidance of the excavating machine as the trench is made. At the lower end of the frame is fixed a cutting head. These machines are in themselves well known and it is therefore sufficient to indicate that the cutting head is usually constituted by two milling motors usually carrying each a pair of drums on which are mounted the milling tools. Each pair of drums rotates about a common axis, the two axes of the mill motors being parallel and horizontal in use. The milling drums are rotated from hydraulic motors.

Different types of mounting are possible.

In a solution proposed in particular by Casagrande, the hydraulic motors are placed at the lower part of the frame of the machine above the cutting head and the power is transmitted to the milling drum by a transmission chain.

Also known by the European patent EP 0 262 050 on behalf of the company Soletanche, a drive mode for milling drums in which the single hydraulic motor is mounted inside the mill drums and connected thereto either by a gear reduction stage or by a direct transmission. The power arrives in hydraulic form in pipes connected to the mill motor.

A second type of such a machine is used for the production of walls molded in the soil obtained by cutting in the soil of a trench having the shape of the wall to be used and by mixing in situ. soil cut with a hydraulic binder. This technique of making molded walls is known as "soil mixing".

The diaphragm wall generally has a smaller depth than the trenches mentioned above. In addition, to allow the extraction of the cutting head out of the mixture "soil cut-hydraulic binder", the frame of the machine has dimensions much smaller. However, the cutting head of these soil mixing machines is also usually constituted by two milling motors each carrying a pair of milling drums.

For this second type of machine, the solution adopted in particular by Bauer, the hydraulic motor is placed on the frame above the cutting head. It transmits power through a shaft of small diameter substantially vertical which passes through the thickness of the plate forming the bearing of the milling motor. The vertical shaft attacks a pair of bevel gears that return motion in the horizontal axis. An epicyclic reduction system reduces the rotation speed and multiplies the torque to effectively drive the mill drums.

The first and third embodiments of soil cutting machine have the major disadvantage of having hydraulic motors above the cutting head and thus to present a more complex and more expensive assembly of these engines. In particular, it is impossible to make rapid exchanges of the cutting head.

In addition, the elements of the transmission kinematic chain of the first and third embodiments (gear, reducer, chain) introduce significant losses of efficiency of the order of 15% which is exempt from the solution described in the European patent of Soletanche company.

Moreover, when each cutter motor drives two cutter drums, it is important that the different conditions of rotation resistance of the drums due to the inhomogeneity of the grounds encountered by the machine do not induce any damaging effect on the mechanical strength of the drills. strawberry motors.

The document is also known DE 195 39 248 which discloses a cutting head according to the preamble of claim 1.

An object of the present invention is to provide a cutting head for a rotary milling cutter which offers better performance in terms of torque and / or speed than prior machines and which improves the mechanical strength of the motor (s). of strawberry.

• deux moteurs hydrauliques comportant chacun un stator et un rotor, et ayant un axe commun ;
• un arbre unique s'étendant selon ledit axe commun et ayant deux extrémités ;
• deux tambours de fraise montés rotatifs ; et
• deux ensembles de transmission pour relier cinématiquement chaque extrémité de l'arbre commun à un desdits tambours de fraise.

To achieve this object, according to the invention, the cutting head for soil cutting machine is constituted by at least one milling motor which comprises:

• two hydraulic motors each having a stator and a rotor, and having a common axis;
• a single tree extending along said common axis and having two ends;
• two rotary mounted milling drums; and
• two transmission assemblies for kinematically connecting each end of the common shaft to one of said milling drums.

• des moyens mécaniques pour solidariser en rotation directement le rotor de chaque moteur hydraulique à l'ensemble de transmission correspondant au tambour de fraise le plus proche du moteur hydraulique.

The cutting head is characterized in that it further comprises:

• mechanical means for directly rotating the rotor of each hydraulic motor to the transmission assembly corresponding to the milling drum closest to the hydraulic motor.

It is understood that thanks to the provisions of the invention, all two milling drums mounted on the same shaft is driven simultaneously by the two hydraulic motors. This allows for greater power to drive a milling drum. The shaft common to the two hydraulic motors simply makes it possible to synchronize the rotation of the two drums when they are both in soils of the same resistance to cutting. This facilitates the rectilinear movement of the excavating machine.

On the other hand, when one of the drums is blocked by the nature of the ground, the other drum remaining free in rotation, the presence of the mechanical means of direct connection between the locked drum and the associated hydraulic motor prevents the portion of the shaft common between this drum and the hydraulic motor alone supports the sum of the torques exerted by the two hydraulic motors since there is no direct mechanical connection between the rotors of the hydraulic motors and the common shaft. This direct mechanical connection transmits the torque applied by the hydraulic motor closest to the locked drum, the common shaft having to bear only the torque applied by the other hydraulic motor to the other drum.

According to a preferred embodiment, each transmission assembly comprises a disk-shaped structure whose center is integral with an end of said common shaft and whose periphery is integral with one end of a milling drum.

In this case, preferably, the securing means in rotation comprise clamping screws to ensure friction between a face of said disk-shaped structure and a face of the rotor frame.

More preferably, the securing means further comprise pins engaged in holes in the faces of the disk-shaped structure and the rotor housing.

• une plaque de fixation ;
• une structure de montage solidaire de la plaque de fixation présentant une partie centrale et deux ensembles de montage disposés de part et d'autre du plan médian de la plaque de fixation, chaque moteur hydraulique étant monté dans un desdits ensembles de montage ;
• une pluralité de conduites ménagées dans l'épaisseur de ladite plaque de fixation pour la circulation du liquide utilisé par les moteurs hydrauliques ; et
• une pluralité de canalisations ménagées dans ladite partie centrale de la structure de montage, lesdites canalisations étant raccordées d'une part auxdites conduites, et d'autre part auxdits moteurs hydrauliques pour raccorder chacun desdits moteurs à chacune desdites conduites.

In addition, preferably, each bur motor comprises:

• a fixing plate;
• a mounting structure integral with the mounting plate having a central portion and two mounting assemblies disposed on either side of the median plane of the mounting plate, each hydraulic motor being mounted in one of said mounting assemblies;
• a plurality of pipes arranged in the thickness of said fixing plate for the circulation of the liquid used by the hydraulic motors; and
• a plurality of ducts in said central part of the mounting structure, said ducts being connected on the one hand to said ducts, and on the other hand to said hydraulic motors for connecting each of said motors to each of said ducts.

It will be understood that the supply of fluid and the recovery of the fluids leaving the hydraulic motors is optimized since this circulation is obtained, on the one hand, by a plurality of ducts formed in the thickness of the fixing plate and, on the other hand, on the pipes in the central part of the mounting structure. Thus, hydraulic motors are accessible at end of the cutting head and can therefore be relatively easily dismounted.

• les figures 1A et 1B montrent l'ensemble d'une machine d'excavation du type fraise en vue en élévation et en vue de côté ;
• la figure 2 est une coupe verticale d'un moteur de fraise pour en exposer les éléments essentiels ;
• la figure 3 est une vue d'un moteur de fraise en section selon la ligne A-A de la figure 2 ; et
• la figure 4 est une vue de détails de la figure 2 montrant un exemple préféré de réalisation des moyens de liaison mécanique directe.

Other features and advantages of the invention will appear better on reading the following description of an embodiment of the invention given by way of non-limiting example. The description refers to the appended figures, in which:

• the Figures 1A and 1B show the whole of a strawberry-type excavation machine in elevation and side view;
• the figure 2 is a vertical section of a strawberry motor to expose the essential elements;
• the figure 3 is a view of a cutter motor in section along line AA of the figure 2 ; and
• the figure 4 is a detail view of the figure 2 showing a preferred embodiment of the direct mechanical connection means.

On the Figures 1A and 1B the assembly of a soil cutting machine has been represented in a simplified manner so as to make a deep trench. This machine is constituted by a frame 12 of relatively large length and of substantially rectangular horizontal section. The upper end 12a of the chassis is equipped with pulleys 14 on which passes a muffle levitation of the mill 12. On the lower end 12b of the frame 12 are attached two identical milling motors 16 and 18 forming the cutting head. Each cutter motor 16 or 18 essentially consists of a fixing plate 20 on which are mounted two milling drums 22 and 24 symmetrical with respect to the median plane of the fixing plate 20. The invention relates to the rotary drive of milling drums 22, 24 of the milling motors 16 and 18.

The suction nozzle 17 for the cut soil debris and the suction pump 19 thereof have also been included.

However, it goes without saying that the cutting head which will be defined in the following description could be part of a "soil mixing" machine. In this case, the upper frame of the machine would be lighter and much smaller than the one shown on the Figures 1A and 1B . It is also obvious that the suction nozzle 17 would be removed and that it would be replaced by one or more injection nozzles in the cut soil of the hydraulic binder.

As has already been explained, one of the essential characteristics of the invention consists in the fact that a direct mechanical connection is made in rotation between the rotor of the two hydraulic motors and the mechanical transmission assembly between the common shaft of the two motors and the drums of strawberry.

The description of the invention which will be made in connection with the Figures 2 to 4 relates to the application of the invention to a milling motor consisting of two hydraulic motors which are mounted in a particular manner at the lower end of the frame of the soil cutting machine, whether it is a chassis important for the realization of trenches of great depths or of a lighter chassis of a machine of "soil mixing". However, it goes without saying that the invention could be applied to other cutter motors since these cutter motors are constituted by two hydraulic motors coupled to the same output shaft.

Referring first to the figure 2 the general organization of the rotational drive of a pair of milling drums 22, 24 constituting a mill motor will be described.

The mill motor 16 comprises a mounting structure 26 which is integral with the fixing plate 20 and engaged in a circular opening 28 of axis XX '. The mounting structure 26 comprises a central portion 30 which is preferably substantially symmetrical with respect to the median plane of the fixing plate 20 and two mounting assemblies 32 and 34 extending symmetrically preferably on either side of the part In the embodiment shown, the mounting assemblies 32 and 34 are constituted by cylindrical shells 36 and 38 which thus define two substantially cylindrical mounting cavities 40 and 42 which are open to the outside. Inside the cavities 40 and 42 which are preferably but not necessarily identical, are mounted the hydraulic motors 44 and 46. Each hydraulic motor comprises a stator 44a, 46a and a rotor 44b and 46b. Each rotor 44b and 46b surrounds a common shaft 50 whose geometric axis coincides with the axis XX 'which is also that of the rotors of the hydraulic motors. The middle portion 50a of the shaft 50 passes through the central portion 30 of the mounting structure by a bore suitably made. The ends 50b and 50c of the shaft 50 are made integral with the transmission assemblies or rims 52 and 54. This attachment can be preferably carried out by splines 55. On these rims 52 and 54 are mounted the milling drums 22 and 24. The rims 52 and 54 are guided and supported by rotation by bearings 56 and 58 which are themselves mounted on the outer face 36a, 38a of ferrules 36 and 38 forming the mounting assemblies of the hydraulic motors. The function of the bearings 56 and 58 is essentially the recovery of the radial and axial forces applied by the milling drums during milling operations.

In addition, according to the invention, mechanical systems such as 60 and 62 provide a direct rotational connection respectively between the rotors 44b and 46b of the hydraulic motors 44 and 46 and on the other hand covers 64 and 66 constituting part of rims 52 and 54 which connect the ends of the shaft 50 to the milling drums 22 and 24. Thus, the milling drums are integral in rotation with the motor rotors by the mechanical systems 60 and 62. An embodiment of these systems mechanics will be described in connection with the figure 4 . The shaft 50 simply connects the strawberry drums together.

The flow of liquids necessary for the operation of the hydraulic motors and their environment is carried out as follows. Pipes such as 70 are drilled in the thickness of the fixing plate 20. One end thereof is connected to supply or discharge lines disposed on the frame of the cutter and their other lower end is connected to pipelines represented schematically by 72 on the figure 2 . As will be explained later in the embodiment considered, there are five supply lines 70 which respectively correspond to the high pressure supply of the hydraulic motors, the low pressure oil return of the hydraulic motors, the drainage internal leakage of the hydraulic motors, to an oil line transmitting a balancing pressure on the seals of the mill motor to prevent penetration of the drilling mud within the mill motors themselves.

Pipes such as 72 are made in the central portion 30 of the mounting structure. These pipes are preferably symmetrical for feeding or recovering liquids in the same way for the two hydraulic motors 44 and 46.

Insofar as the pipes 72 must feed the rotating parts of the hydraulic motors, these pipes end in distribution systems such as 74 and 76 commonly called windows which provide a rotating connection between the supply lines and the hydraulic inputs or outputs of the rotors 44b and 46b.

It will be understood that insofar as each duct 72 symmetrically feeds the windows 74 and 76 corresponding to the hydraulic motors 44 and 46, the pressure exerted by the liquid or the oil on the supply faces of the rotors of the hydraulic motors 44 and 46 are identical and thus equilibrate axially. One of the advantages of this embodiment is therefore not to require the introduction of bearings or stops to resume axial thrusts in the direction of the axis XX 'which would be due to the feed liquids.

On the figure 3 , the lines 70 and the pipes 72 have been shown in greater detail. In particular, the five supply lines 70a to 70e have been shown in the thickness of the fixing plate 20.

The lower ends of the pipes 70a to 70e are connected to the pipes 72a to 72e which extend symmetrically in the central portion 26 of the mounting structure. The ends of these pipes are connected to the windows of communication with the rotating parts of the hydraulic motors. The lines 72a to 72e which serve for the high-pressure supply and the low-pressure output of the hydraulic motors 44 and 46 are located at the same distance from the axis XX 'of the central portion 26.

On the figure 4 , there is shown in more detail a part of a preferred embodiment of the mechanical systems for direct connection in rotation between a milling drum and the hydraulic motor associated therewith.

In this figure, there is one of the two hydraulic motors 44 with its rotor 44b. The end 50b of the shaft is secured to the cover 64 which is part of the rim 52 on which is mounted a milling drums 22 not shown in this figure. The end face 45 of the frame of the rotor 44b is secured to the cover 64 of the rim 52 by mechanical systems referenced 60 and 62 on the figure 2 .

In the embodiment shown on the figure 4 each cover 64 is constituted by two pieces bolted together 64a, 64b.

Preferably, these mechanical systems 60 and 62 are constituted by an alternation of pins 80 and screws 82 regularly arranged around the axis XX 'of the hydraulic motors.

The purpose of the screws 80 is to ensure a high friction between the end face 45 of the rotor 44b and the internal face 63 of the cover 64, so as to lock the rotor and the rim 52 in rotation.

The purpose of the pins 80 is to complete, if necessary, the securing carried out by the screws 82. They are housed in blind holes formed in the face 45 of the rotor of each hydraulic motor and in blind holes made in the internal face 63 of the rim cover.

Claims (6)

1. A cutter head for a ground cutter machine having at least one cutter motor (16), each cutter motor comprising:

   - two hydraulic motors (44, 46), each comprising a stator (44a, 46a) and a rotor (44b, 46b) and having a common axis (XX');

   - a single shaft (50) extending along said common axis and having two ends;

   - two cutter drums (22, 24) mounted to rotate; and

   - two transmission assemblies (52, 54, 64, 66) for drivingly connecting each end (50b, 50c) of the common shaft to one of said cutter drums;

   said cutter head being characterized in that it further comprises:

   - mechanical members (60, 62) for constraining the rotor (44b, 46b) of each hydraulic motor directly in rotation with the transmission assembly corresponding to the cutter drum (22, 24) that is closer to the hydraulic motor.
2. A cutter head according to claim 1, characterized in that each transmission assembly comprises:

   a disk-shaped structure (64, 66) having its center secured to one end (50b, 50c) of said common shaft (50) and having its periphery secured to one end of a cutter drum (22, 24).
3. A cutter head according to claim 2, characterized in that the members for providing constraint in rotation comprise clamping screws (82) for providing friction between a face of said disk-shaped structure and a face of the rotor structure.
4. A cutter head according to claim 2 or claim 3, characterized in that the constraining members further comprise pegs (80) engaged in holes formed in the face of the disk-shaped structure (64, 66) and in the face of the rotor structure.
5. A cutter head according to any one of claims 1 to 4, characterized in that each cutter motor further comprises:

   - a fastener plate (20);

   - a mounting structure (26) secured to the fastener plate and presenting a central portion (30) and two mounting assemblies (32, 34) disposed on either side of the midplane of the fastener plate, each hydraulic motor (44, 46) being mounted in one of said mounting assemblies (32, 34);

   - a plurality of conduits (72) formed in the thickness of said fastener plate (20) for passing the liquid used by the hydraulic motors; and

   - a plurality of ducts (72) formed in said central portion (30) of the mounting structure (26), said ducts being connected firstly to said conduits and secondly to said hydraulic motors for connecting each of said motors (44, 46) to each of said conduits.
6. A cutter head according to claim 5, characterized in that the two hydraulic motors (44, 46) are substantially identical and in that they are substantially symmetrical about the midplane (A, A') of the fastener plate (20).

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