Ground milling machine and method to operate a ground milling machine

Abstract

A ground milling machine, in particular a soil stabilizer or a recycler, comprising a machine frame carried by front and rear traveling devices, a drive engine arranged on the machine frame, a ground milling device with a milling rotor supported for rotation about a horizontal rotation axis extending transversely to the working direction of the ground milling machine, said milling rotor having a plurality of ground processing tools, and with a milling rotor housing having an interior space which is open in the downward direction towards the underlying ground and in which the milling rotor is arranged, said milling rotor being height-adjustable via a milling depth adjusting device having a drive, and said milling rotor housing being connected to the machine frame via a housing support device. The invention further relates to a method for operating a ground milling machine. According to an essential aspect of the invention, provision is made for a lifting movement of the front edge of the milling rotor housing relative to the machine frame depending on the milling depth.

Claims

1. A ground milling machine, comprising: a machine frame carried by front and rear traveling devices, comprising a drive engine arranged on the machine frame; a ground milling device with a milling rotor supported for rotation about a horizontal rotation axis extending transversely to a working direction of the ground milling machine, said milling rotor having a plurality of ground processing tools, and with a milling rotor housing having an interior space which is open in a downward direction towards underlying ground and in which the milling rotor is arranged; said milling rotor being height-adjustable via a milling depth adjusting device having a drive; and said milling rotor housing being connected to the machine frame via a housing support device, wherein a housing adjusting device is provided which is configured to adjust a position of the milling rotor housing relative to the machine frame depending on a milling depth of the milling rotor such that a front edge of the milling rotor housing is lifted with increasing the milling depth, which enlarges free space underneath the milling rotor housing towards the milling rotor and the underlying ground, and vice versa.

2. The ground milling machine according to claim 1, wherein the housing adjusting device is configured such that, for lifting the front edge, the milling rotor housing rotates about an axis such that a vertical distance of a rear edge of the milling rotor housing from the machine frame remains essentially constant.

3. The ground milling machine according to claim 1, wherein the housing adjusting device has a sensor device for ascertaining the milling depth, a control unit, and an adjusting drive for adjusting the position of the milling rotor housing relative to the machine frame, said control unit controlling the adjusting drive depending on a currently ascertained milling depth.

4. The ground milling machine according to claim 1, wherein the housing adjusting device and the milling depth adjusting device are coupled to one another, and that both the milling depth adjusting device and the housing adjusting device are jointly driven via the drive of the milling depth adjusting device.

5. The ground milling machine according to claim 1, wherein the housing adjusting device has an adjusting mechanism.

6. The ground milling machine according to claim 5, wherein the adjusting mechanism is a cam mechanism.

7. The ground milling machine according to claim 5, wherein the adjusting mechanism comprises at least one of the following features: a control cam integrated into a sidewall of the milling rotor housing, said control cam being traced by a rotor swivel arm or an element moved together with said rotor swivel arm; and a swivel thrust joint in a swivel lever which connects the machine frame to the milling rotor housing.

8. The ground milling machine according to claim 1, wherein the housing adjusting device is configured to control not only a lifting movement of the milling rotor housing but also a horizontal displacement of the milling rotor housing such that the milling rotor housing is displaced in the working direction towards the front relative to the machine frame and relative to the milling rotor with increasing milling depth, and vice versa.

9. The ground milling machine according to claim 1, wherein the housing adjusting device is configured such that a horizontal displacement and a lifting movement of the milling rotor housing occur at least partially concurrently across a range between a position in which the milling rotor rests on a non-milled underlying ground and a maximally lowered milling rotor.

10. The ground milling machine according to claim 1, wherein the ground milling machine is a soil stabilizer or recycler.

11. A method for operating a ground milling machine, comprising: obtaining the ground milling machine, the ground milling machine comprising a machine frame carried by front and rear traveling devices, comprising a drive engine arranged on the machine frame; a ground milling device with a milling rotor supported for rotation about a horizontal rotation axis extending transversely to a working direction of the ground milling machine, said milling rotor having a plurality of ground processing tools, and with a milling rotor housing having an interior space which is open in a downward direction towards underlying ground and in which the milling rotor is arranged; said milling rotor being height-adjustable via a milling depth adjusting device having a drive; and said milling rotor housing being connected to the machine frame via a housing support device, wherein a housing adjusting device is provided which is configured to adjust a position of the milling rotor housing relative to the machine frame depending on a milling depth of the milling rotor such that a front edge of the milling rotor housing is lifted with increasing the milling depth, which enlarges free space underneath the milling rotor housing towards the milling rotor and the underlying ground, and vice versa; adjusting milling depth with the milling depth adjusting device; and adjusting the position of the milling rotor housing relative to the machine frame with the housing adjusting device.

12. The method according to claim 11, further comprising starting from an initial position in which the milling rotor rests on a non-milled underlying ground, and lifting the front edge of the milling rotor housing only upon an exceedance of a threshold milling depth.

13. The method according to any one of claim 11, further comprising lifting the front edge of the milling rotor housing such that a rear edge of the milling rotor housing essentially maintains a vertical position relative to the machine frame.

14. The method according to claim 11, further comprising displacing of the milling rotor housing in the working direction towards the front is performed in addition to lifting of the front edge of the milling rotor housing with increasing milling depth.

15. The method according to claim 14, wherein the displacing of the milling rotor housing in the working direction towards the front is performed at least partially concurrently with a lifting of the front edge of the milling rotor housing depending on an exceedance of a threshold milling depth.

16. The method according to claim 11, further comprising lifting of the front edge of the milling rotor housing by tracing a control cam by a rotor swivel arm or an element that is movable together with said rotor swivel arm, and by running along a slot guide in a swivel thrust lever which connects the machine frame to the milling rotor housing.

17. The method according to claim 11, wherein adjusting the position of the milling rotor housing is forcibly coupled to adjusting of the milling depth.

18. The method according to claim 11, wherein adjusting the position of the milling rotor housing and the adjusting of the milling depth are driven by a shared drive.

19. A ground milling machine, comprising: a machine frame carried by front and rear traveling devices, comprising a drive engine arranged on the machine frame; a ground milling device with a milling rotor supported for rotation about a horizontal rotation axis extending transversely to a working direction of the ground milling machine, said milling rotor having a plurality of ground processing tools, and with a milling rotor housing having an interior space which is open in a downward direction towards underlying ground and in which the milling rotor is arranged; said milling rotor being height-adjustable via a milling depth adjusting device having a drive; and said milling rotor housing being connected to the machine frame via a housing support device, wherein a housing adjusting device is provided which is configured to adjust a position of the milling rotor housing relative to the machine frame depending on a milling depth of the milling rotor such that a front edge of the milling rotor housing is lifted with increasing the milling depth and vice versa, and wherein the housing adjusting device has a sensor device for ascertaining the milling depth, a control unit, and an adjusting drive for adjusting the position of the milling rotor housing relative to the machine frame, said control unit controlling the adjusting drive depending on a currently ascertained milling depth.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail below by reference to the embodiment examples indicated in the figures. In the schematic figures:

(2) FIG. 1 is a side view of a ground milling machine in milling operation at small milling depth with non-lifted milling rotor housing, i.e. with the milling rotor housing in the zero position;

(3) FIG. 2 is a side view of a ground milling machine in milling operation at large milling depth with lifted milling rotor housing;

(4) FIG. 3 is an enlarged cut-out view of the region I of FIG. 1;

(5) FIG. 4 is an enlarged cut-out view of the region I of FIG. 2;

(6) FIG. 5 is a graphical representation of a concurrence of a lifting movement and a displacing movement of the milling rotor housing relative to the machine frame;

(7) FIG. 6 is a graphical representation of an alternative concurrence of a lifting movement and a displacing movement of the milling rotor housing relative to the machine frame;

(8) FIG. 7 is a graphical representation of an alternative concurrence of a lifting movement and a displacing movement of the milling rotor housing relative to the machine frame; and

(9) FIG. 8 is a flowchart for operating a ground milling machine.

DETAILED DESCRIPTION

(10) Like components are designated by like reference numerals in the figures, although not every recurring component is necessarily designated separately throughout the figures.

(11) FIG. 1 shows a ground milling machine 1, in this case of the soil stabilizer and/or recycler type, in milling operation at small milling depth FT. Essential elements of the ground milling machine 1 include a machine frame 2, which in the present case is an articulated machine frame having a front frame 2A and a rear frame 2B. A continuous machine frame 2 without articulation may also be used. The ground milling machine 1 further comprises a drive engine 3, a driver's cab 4 as well as front traveling devices 5A and rear traveling devices 5B, in the present case wheels, although crawler tracks may be used as well. The drive engine 3 produces the drive power required for traveling and milling operation. The ground milling machine 1 is operated from the operator platform 4. Generally, and regardless of the present embodiment example, the ground milling machine 1 may be self-propelled.

(12) Another essential element of the ground milling machine 1 is a ground milling device 6, which is arranged on the machine frame 2 between the front traveling devices 5A and the rear traveling devices 5B. Essential elements of the ground milling device 6 include a milling rotor 7 and a milling rotor housing 8. The milling rotor 7 is arranged inside the milling rotor housing 8, which is open towards the underlying ground B, and may, for example, have a support tube not shown in further detail having an outer circumferential surface on which a plurality of milling tools is arranged. The milling rotor housing 8 shields the milling rotor 7 from the outside environment towards the top, the face sides and the front and rear, enabling a controlled guidance of milled material inside the milling rotor housing 8. The milling rotor 7 is arranged inside the milling rotor housing for rotation about a horizontal rotation axis R extending transversely to the working direction A and protrudes in vertical downward direction beyond the bottom edge of the milling rotor housing 8 by the milling depth FT during milling operation. The milling rotor 7 is height-adjustable to enable the milling depth FT to be varied and the milling rotor 7 to be lifted out of the underlying ground, for example for a transportation operation. The height adjustment of the milling rotor 7 is performed via a milling depth adjusting device 9 having as its essential elements an adjusting drive 10 as well as a rotor swivel arm 11. The rotor swivel arms 11 are provided as a pair and are arranged at both face sides of the milling drum 7 (only the left rotor swivel arm 11 being visible in the side view of FIG. 1). The rotor swivel arm 11 is articulated to the machine frame 2 about a horizontal swivel axis S extending transversely to the working direction A. The swivel movement of the rotor swivel arm 11 is driven via the adjusting drive 10, which in the present embodiment example is a hydraulic cylinder arranged between the machine frame 2 and the rotor swivel arm 11. When the hydraulic cylinder is retracted, the rotor swivel arms 11 swivel upwards about the swivel axis S while carrying the milling rotor 7 along, and vice versa. This is illustrated, for example, by a comparison of FIG. 1, in which a comparably small milling depth FT is shown, with the side view of FIG. 2, in which the ground milling machine 1 of FIG. 1 is shown at a comparably large milling depth FT.

(13) The milling rotor housing 8 is, on the one hand, connected to the machine frame 2 of the ground milling machine 1 via a housing support device 12, which in the present embodiment example is a connection chain suspended vertically from the machine frame 2 and articulated to the rear region of the milling rotor housing 8. The milling rotor housing 8 further comprises a front edge 13, which in the present case designates the region of the milling rotor housing 8 located in the working direction A at the front, i.e. the front bottom edge of the milling rotor housing 8 in the working direction A, and a rear edge 14, which in the present case designates the region of the milling rotor housing 8 located in the working direction A at the rear (i.e. the rear bottom edge in the working direction A). The milling rotor housing 8 further has a respective sidewall 15 at both face sides of the milling rotor 7. Provided in said sidewall 15 is an elongated recess 16 through which a support connection extends from the inner side of the respective rotor swivel arm 11 to the milling rotor 7 arranged inside the milling rotor housing 8.

(14) An essential feature of the ground milling machine depicted in FIGS. 1 and 2 now consists in the fact that a housing adjusting device 17 is provided which effects an adjustment of the position of the milling rotor housing 8 relative to the machine frame 2 such that the milling rotor housing 8 is lifted in the region of its front edge 13 relative to the rear edge 14 of the milling rotor housing 8 with increasing milling depth FT. This is illustrated by a comparison of FIG. 1 with FIG. 2. In FIG. 1, the distance of the front edge 13 of the milling rotor housing 8 is designated with ΔH. Starting from FIG. 1, the milling depth FT is enlarged towards FIG. 2 by a downward swiveling of the rotor swivel arms 11. The housing adjusting device 17 here causes an enlargement of the distance ΔH of the front edge 13 of the milling rotor housing 8 simultaneously with the increase in milling depth FT by adjusting the position of the milling rotor housing 8 relative to the machine frame 2, more specifically by lifting the front edge 13 relative to the machine frame. The rear edge 14, on the other hand, essentially maintains its position, i.e. its position relative to the machine frame 2, at both milling depths. The milling rotor housing 8 thus essentially tilts or rotates about the connection joint 18 between the connection chain of the housing support device 12 and the milling rotor housing 8.

(15) An essential advantage of the arrangement shown in FIGS. 1 and 2 is that, as will be described in more detail below, only one single shared drive, more specifically the adjusting drive 10, is required for both the height adjustment of the milling rotor 7 as well as the movement of the milling rotor housing 8 in the manner described above. The milling depth adjusting device 9 and the housing adjusting device 17 are thus forcibly coupled to one another, so that an adjustment of the milling depth with the aid of the milling depth adjusting device 9 at the same time causes a change in the position of the milling rotor housing 8 relative to the machine frame 2 with the aid of the housing adjusting device 17.

(16) For further illustration, FIGS. 3 and 4 now show enlarged cut-out views of the region I of FIG. 1 (in FIG. 3) and of FIG. 2 (in FIG. 4). The sequence of motions of the milling rotor housing 8 as described above is thus achieved via the housing support device 12 articulated in the rear region of the milling rotor housing 8 on the one hand and the housing adjusting device 17 on the other hand. Essential elements of the housing adjusting device 17 include a control cam 19 (partially covered by the rotor swivel arm 11 in FIGS. 3 and 4) as well as a swivel thrust lever 20 with a slot guide 21. The control cam 19 is formed by the recess 16 (in the figures partially covered by the rotor swivel arm 11 and in this region partially indicated with dashed lines) in the sidewall 15 of the rotor housing 8. A slide member 22, which is covered by the rotor swivel arm 11 in the figures (indicated with dashed lines in FIGS. 3 and 4), runs along the control cam 19 on the rotor housing 8 side, said slide member being movable together with the rotor swivel arm 11 and resting against the front edge of the recess 16 in the working direction A forming the control cam 19. Upon adjustment of the adjusting drive 10, which in the present case is a hydraulic cylinder, the resulting swivel movement of the rotor swivel arm 11 about S thus also controls the position of the rotor housing 8 relative to the machine frame 2 via the control cam 19.

(17) The swivel thrust lever 20 is articulated to the machine frame 2 and the rotor housing 8 via the joints 20A and 20B, respectively. The joint 20B is formed by a slot 21 extending in the swivel thrust lever 20 in the longitudinal direction of the swivel thrust lever 20, said slot being engaged by a connection pin 23 which is displaceable along the slot 21 and is fixedly arranged on the rotor housing 8. All in all, the arrangement described above thus forms a cam mechanism with the four hinge points 20A, 20B, S and the resting point of the slide member 22 on the control cam 19. The mechanical connection between the slide member 22, i.e. the rotor swivel arm 11, and the control cam 19 has the effect that the milling depth adjusting device 9 and the housing adjusting device 17 are essentially forcibly coupled in a mechanical manner, and thus a height adjustment of the milling rotor 7 about the swivel axis S caused by the adjusting drive 10 is also translated into a movement of the rotor cover 8 relative to the machine frame 2, said movement thus being dependent on the current milling depth.

(18) As a result of the slot guide 21 arranged in the swivel thrust lever 20, the forced translation of the height adjustment of the milling rotor 7 into the lifting movement of the front edge 13 of the milling rotor housing 8 occurs only in certain phases, i.e. when, during a lowering of the milling rotor 7 for height adjustment of the milling rotor 7, the connection pin 23 abuts the abutment end of the slot guide 21 located closer to the hinge point 20A. Only then will the swivel thrust lever 20 transmit a thrust force such that, upon a continued downward swiveling of the rotor swivel arm 11, the slide member 22 resting against the control cam 19 pushes the milling rotor housing 8 in the working direction A towards the front in the bottom region and the swivel thrust lever 20 pushes the milling rotor housing 8 against the working direction A at the hinge point 20B in the top region of the milling rotor housing. This ultimately results in the upward swivel movement of the front edge 13 of the milling rotor housing 8 about the articulation point of the connection chain 12 at the milling rotor housing 8. As a result of the slot, a threshold milling depth is defined upon exceedance of which the upward swivel movement of the front edge of the rotor housing relative to the machine frame occurs as described above.

(19) FIGS. 5, 6 and 7 now show several exemplary solutions as to how to implement the movements of the milling rotor housing 8 relative to the machine frame 2 in various variants through a corresponding adaptation of the housing adjusting device 17, in particular the control cam 19, the swivel thrust lever 20 and the slot guide 21. The upper graph in each case shows the upward swivel movement AB of the front edge 13 about the rotation point of the milling rotor housing 8, i.e. the angular change of the milling rotor housing 8 with respect to a swivel axis extending transversely to the working direction A and horizontally (for example at the articulation point of the connection chain at the milling rotor housing, as described above), starting from the zero position of the milling rotor housing 8, i.e. the position of the milling rotor housing 8 in which the milling rotor 7 either rests on the non-machined, non-milled underlying ground, in particular together with the milling rotor housing 8 (milling depth FT0) or has such a minimum milling depth FT0 that the milling rotor housing 8 just comes into contact with the underlying ground during the lowering of the rotor swivel arm 11. The lower graph in each case shows the horizontal displacement HV of the milling rotor housing 8 in the working direction A towards the front, also starting from the zero position of the milling rotor housing 8.

(20) In the embodiment example according to FIG. 5, the horizontal displacement of the milling rotor housing 8 in the working direction towards the front starts at a milling depth FT0. The milling rotor housing 8 in this case maintains the height position of the front edge 13 until the milling depth FT1 is reached. Upon exceedance of the threshold milling depth FT1, the forced coupling described above engages and the housing adjusting device 17 effects the lifting of the front edge 13 of the milling rotor housing 8 simultaneously with the horizontal displacement of the milling rotor housing until the maximum milling depth, and thus the maximum horizontal displacement and the maximum upward swivel position of the milling rotor housing 8, is reached at the milling depth FT2.

(21) According to the alternative embodiment example of FIG. 6, the horizontal displacement of the milling rotor housing 8, which occurs from the milling depth FT0 to the milling depth FT1, alternates with the lifting movement of the front edge 13 of the milling rotor housing 8, which occurs from the milling depth FT1 to the maximum milling depth FT2. According to another alternative, which is not shown, for example, the forced coupling, and thus the horizontal displacement and simultaneously also the lifting movement of the front edge 13 of the milling rotor housing 18, occur simultaneously across the entire range from FT0 to FT2.

(22) The embodiment example of FIG. 3 differs from the above variants in that the horizontal displacement HV and the upward swivel movement overlap only partially. A horizontal displacement of the milling rotor housing 8 in the working direction A towards the front is performed in the milling depth range from FT0 to FT1B, and an upward swivel movement AB of the front edge 13 of the milling rotor housing 8 is performed in the milling depth range from FT1A to FT2. A simultaneous movement AB and HV of the milling rotor housing 8 occurs only in the milling depth range from FT1A to FT1B. In this respect, the upward swivel movement AB and the horizontal displacement HV thus each have their own threshold milling depth FT1A and FT1B, respectively.

(23) Instead of the linear curve shapes shown, curved shapes are obviously also possible.

(24) FIG. 8 finally illustrates the sequence of a method according to the invention which may be carried out in particular with a ground milling machine 1 shown in any of the preceding figures. Step S1 initially involves the lowering of the milling rotor 7 until said rotor and/or the milling rotor housing 8 rests on the underlying ground in its zero position. Depending on the design of the milling rotor housing 8, the milling rotor 7 may already engage the underlying ground at a small milling depth at this point. This corresponds to the milling depth FT0. If the milling depth is now increased further by a continued lowering of the milling rotor 7 via the milling depth adjusting device 9, for example until the maximum milling depth FT2 is reached in step S2, a lifting S3 of the front edge 13 of the milling rotor housing 8 is performed during at least parts of this lowering process, wherein the extent of the lifting movement depends on the current milling depth. The larger the milling depth FT (at least starting from the exceedance of a threshold milling depth), the larger the vertical distance of the front edge 13 from the underlying ground, and vice versa. Step S4 may involve a simultaneous or alternating horizontal displacement of the milling rotor housing 8 relative to the machine frame 2 in the working direction towards the front in connection with steps S1 and S2. In step S5, steps S3 and S4 may preferably be driven together by a single drive device as shown in FIG. 8, i.e. a shared actuator, in particular the adjusting drive 10 of the rotor swivel arm 11, for example using a mechanically forced coupling, or they may each be driven by their own drive device, i.e. their own actuator.