Ground milling machine and method of operating a ground milling machine

Abstract

Ground milling machine, in particular stabilizer or recycler, and method, characterized by a roller flap position correction mode, which can be activated manually or automatically after the ground milling machine has been started, after the application of milling / mixing rollers or after an increase in milling depth. In the roller flap position correction mode, the position of the rear roller flaps is optimized, thereby largely avoiding the accumulation of material and the problems resulting therefrom. The control device of the roller flap adjustment device is designed such that, in the roller flap correction mode, in a first step the floating position of the rear roller flaps is cancelled and the rear roller flaps are pivoted upward from a first pivot position into a second pivot position. In a second step, the floating position is set again such that the rear roller flaps are in a third pivot position in which the lower edge of the rear roller flaps rests on the ground. After the floating position is reset, a check routine comprising at least one check cycle is carried out.

Description

TECHNICAL FIELD

[0001] The invention relates to a ground milling machine, in particular a stabilizer or a recycler, having a machine frame which is supported by a running gear and on which a milling / mixing drum is arranged, which is arranged in a drum housing which is open at the bottom and has a drum flap at the rear in the direction of travel, which can be pivoted about a pivot axis which extends transversely to the longitudinal direction of the ground milling machine. Furthermore, the invention relates to a method for operating such a ground milling machine. BACKGROUND

[0002] In order to stabilize ground which has insufficient load-bearing capacity, stabilizers are known which increase the load-bearing capacity of the ground by introducing a powder-like or liquid binder into the ground. Self-propelled and non-self-propelled stabilizers are known which are attached to or towed by a towing vehicle. Known recyclers differ from stabilizers in that recyclers are not only used to improve or consolidate the ground, but also to repair damaged surface layers of roads or paths.

[0003] The stabilizer or recycler has a machine frame on which a milling / mixing drum is arranged for milling the ground to be stabilized or the road surface layer to be repaired, which is located in a drum housing which is open at the bottom. The drum housing has a drum flap at the front in the direction of travel and a drum flap at the rear in the direction of travel, and these flaps can be pivoted about a pivot axis which extends transversely to the longitudinal direction of the machine frame. The drum housing is closed at the sides by side parts which extend in the longitudinal direction.

[0004] The volume enclosed by the drum housing forms a mixing chamber for the milled material and the binder. One or more dosing devices are located on the drum housing, which dosing devices provide the volume of the mixing chamber with predetermined amounts of possibly different binders or water.

[0005] In order to pivot the drum flap at the front and the drum flap at the rear, a drum flap adjustment device is provided, which has at least one actuator for pivoting the drum flap at the front or the drum flap at the rear and a control device for operating the at least one actuator, so that the height of the lower edge of the drum flap at the front or the drum flap at the rear relative to the ground is adjustable. The control device of the drum flap at the rear is designed in such a way that during the milling operation the at least one actuator is controlled so that the drum flap at the rear rests on the ground in a floating position with a predetermined contact force.

[0006] In addition, known stabilizing or recycling machines have a milling / mixing roller adjustment device that is designed in such a way that the height of the milling / mixing roller relative to the machine frame can be adjusted, thereby changing the milling depth.

[0007] When milling / mixing rollers are applied and milling operations begin, and as the milling depth increases during the operation, the rear roller flaps exert considerable back pressure on the material in the roller housing, even in the floating position. Practice has shown that this back pressure can cause material to accumulate in the mixing chamber. If material accumulation occurs, the mixing ratio of material and binder can no longer meet specifications. Another disadvantage is the need for higher power to operate the milling / mixing rollers, or the milling process can only be performed at lower operating speeds.

[0008] After applying milling / mixing rollers or after increasing milling depth, raising the lower edge of the rear roller flaps can facilitate the outflow of accumulated material from the roller housing as the milling machine advances. However, if the rear roller flaps open too far, there is a risk that material will be thrown backward from the roller housing. Summary of the Invention

[0009] The object of this invention is to improve the operation or working results of a ground milling machine, particularly when initiating milling with a milling / mixing roller or when increasing the milling depth during milling. Specifically, one object of the invention is to avoid material buildup when using the milling / mixing roller or when increasing the milling depth, or to ensure an optimal mixing ratio of the milled material and binder. Another object of the invention is to avoid increasing the power required to operate the milling / mixing roller, or to avoid reducing the working speed when using the milling / mixing roller or when increasing the milling depth.

[0010] Another object of the present invention is to provide a method, particularly when milling is initiated with milling / mixing rollers or when the milling depth is increased during milling, to operate a ground milling machine to avoid material buildup.

[0011] According to the invention, these objectives are achieved by the features of the independent claims. The dependent claims relate to advantageous embodiments of the invention.

[0012] The ground milling machine according to the invention, particularly a stabilizer or recovery machine, and the method according to the invention, are characterized by a roller tilting plate position correction mode, which can be manually or automatically activated after the milling / mixing rollers are applied and the ground milling machine is started, or during actual milling operation after an increase in milling depth. The roller tilting plate position correction mode includes at least one roller tilting plate position correction cycle to optimize the position of the rear roller tilting plates, thereby largely avoiding material buildup and the resulting problems. The roller tilting plate position correction mode can be manually activated by the machine operator or can be activated fully automatically, thus human intervention is not necessary. No human intervention is required when operating the ground milling machine in roller tilting plate position correction mode. After the roller tilting plate position is corrected, the roller tilting plate position correction mode can be automatically deactivated again.

[0013] The control device of the roller tilting adjustment device is designed such that, in at least one roller tilting correction cycle, in the first step, the floating position of the rear roller tilting is canceled, and the rear roller tilting is pivoted upward from the first pivoting position to the second pivoting position, causing the lower edge of the rear roller tilting to rise. Therefore, material accumulated in the roller housing can flow out. The pivoting angle of the roller tilting upward can be specified by the control device. On the one hand, the roller housing should open wide enough so that the accumulated material can flow out of the roller housing without obstruction, but on the other hand, it should not open too wide, otherwise the risk of material being thrown out is greater. In the second step, after the rear roller tilting has reached the second pivoting position, the floating position is set again so that the rear roller tilting is in the third pivoting position, in which the lower edge of the rear roller tilting rests on the ground.

[0014] In a preferred embodiment, at least one roller tilting plate position correction cycle includes a check routine. The basic principle of the check routine is to monitor the movement of the roller tilting plate after the floating position has been restored.

[0015] The inspection routine specifies that the variable associated with the third pivot position is compared with a threshold, or the variable associated with the third pivot position is compared with the value of the variable associated with the first pivot position, wherein the roller flipper position correction mode is deactivated based on the comparison of the value of the variable associated with the third pivot position with the threshold or based on the comparison of the value of the variable associated with the third pivot position with the value of the variable associated with the first pivot position.

[0016] If the raised roller flap returns to a lower position after the floating position has been reset, meaning it did not remain in the raised position, then a continuous material flow is considered to have been established, where the milled material accumulating in the mixing chamber and the material flowing out of the mixing chamber below the roller flap are in equilibrium, preventing material accumulation. Specifically, it can be checked whether the roller flap has returned to the position from which it was raised. In this case, the roller flap position correction mode can be disabled.

[0017] A threshold can be set for the movement of the roller flapper. If the movement of the roller flapper is less than or equal to the threshold after the floating position is reset, i.e., the roller flapper has not fallen back by the predetermined amount, another roller flapper position correction cycle is executed. Conversely, if the movement of the roller flapper is greater than the threshold, i.e., the roller flapper has fallen back by the predetermined amount, the roller flapper position correction mode is disabled.

[0018] Variables related to pivot position can be those that can be easily detected with minimal technical effort. The evaluation of the variable's value depends on whether it increases or decreases as the milling roll rises. For example, if the variable is a pivot angle, the evaluation depends on which angle is defined as the pivot angle. Different mathematical methods can be used to compare variables related to pivot position before and after the milling roll rises.

[0019] In a preferred embodiment, the variable associated with the first and third pivot positions is a variable related to the height of the lower edge of the rear roller flap. The value of this variable increases when the roller flap opens. In this embodiment, a roller flap position correction cycle is executed until it is determined at least once that the height of the lower edge of the rear roller flap at the third pivot position is equal to or less than the height of the lower edge of the rear roller flap at the first pivot position. Conversely, if the height of the lower edge of the rear roller flap at the third pivot position is greater than the height of the lower edge of the rear roller flap at the first pivot position, a further roller flap position correction cycle is executed. Therefore, the roller flap position correction mode can terminate after only one or more roller flap position correction cycles. Thus, if the lower edge of the rear roller flap at the third pivot position is checked only once to be equal to or less than the height of the lower edge of the rear roller flap at the first pivot position, the roller flap position correction mode can include only one roller flap position correction cycle, and this is also the case. However, the repeated determination of these conditions has the following advantages: the roller position correction mode is only deactivated when the balance state has been permanently set.

[0020] The height of the lower edge of the roll turner is a variable relative to a reference plane, which can be an unmilled surface. If the height of the surface relative to the machine frame or roll housing is known, the height of the lower edge of the roll turner can be determined from the height of the roll turner relative to the machine frame or roll housing.

[0021] At least one actuator of the roller tilting device can be a piston-cylinder assembly acting on the roller tilting device, wherein a measuring unit, particularly a distance sensor, can be provided to detect the position of the piston of the piston-cylinder assembly in order to detect variables related to the first and / or third pivoting positions. For example, the piston of the piston-cylinder assembly may be pivotally attached to the machine frame, while the cylinder may be pivotally attached to the roller tilting device, or vice versa. This embodiment can be easily implemented without significant technical effort. In this embodiment, the pivoting position can be simply compared by comparing the piston's stroke during lifting with its stroke during lowering. If the distance the piston extends during lowering is less than the distance the piston retracts during raising the roller tilting device, i.e., the roller tilting device maintains its upper position or is even raised further by material flow, another roller tilting device position correction cycle is executed. Conversely, if the roller tilting device falls back to a lower position after raising due to the lack of material flow, the check terminates.

[0022] The control device of the roller tilting device is preferably designed such that, in the second step, after a predetermined time interval has elapsed or a predetermined distance has been covered, after the floating position has been cancelled or the roller tilting device has pivoted to the third pivot position, the floating position is reset. The time interval or distance can be measured considering dynamic conditions related to material flow during milling.

[0023] The pivot angle of the roller flap's upward pivoting depends on the volume of material milled away. A further preferred embodiment provides a memory that stores pivot angles for different milling depths or variables related to the pivot angle through which the rear roller flap pivots from a first pivot position to a second pivot position. The control device of the roller flap adjustment device is designed such that, depending on the set milling depth, the pivot angle or variables related to the pivot angle are read from the memory.

[0024] To manually activate the roll tilting position correction mode, the control device of the roll tilting adjustment device may have operating elements, such as knobs, switches, or buttons on a touch screen (touchscreen). The control device is designed in such a way that the roll tilting position correction mode is activated by operating the operating elements.

[0025] The control device for the roller tilting adjustment device can also be designed such that the roller tilting position correction mode is automatically activated after a predetermined time interval has elapsed since the ground milling machine started milling operations or after the ground milling machine has covered a predetermined distance. The start time of the ground milling machine can be determined by monitoring control signals obtainable from the central control and computing unit of the ground milling machine, or by obtaining measurement values ​​from appropriate sensors (e.g., distance sensors).

[0026] Since ground milling machines typically have a milling / mixing roller adjustment device, designed so that the height of the milling / mixing roller relative to the machine frame can be adjusted to change the milling depth, the control device of the roller tilting adjustment device can be designed such that when the milling / mixing roller adjustment device increases the milling depth by a predetermined value during milling operation and after a predetermined time interval has elapsed, or when the milling / mixing roller adjustment device increases the milling depth by a predetermined value during milling operation and the ground milling machine has covered a predetermined distance after the increase in milling depth, the roller tilting position correction mode is activated. The time interval or distance can be measured considering the dynamic conditions during milling operation. The height of the milling / mixing roller relative to the machine frame can be adjusted, wherein the machine frame is supported by lifting columns fixed to the traveling mechanism, allowing the height of the machine frame to be adjusted relative to the ground. Attached Figure Description

[0027] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] In the diagram:

[0029] Figure 1 An embodiment of the ground milling machine according to the present invention is shown in partial cross-sectional view;

[0030] Figure 2 This is a diagram showing the structure of the roller tilting adjustment device and the milling / mixing roller adjustment device;

[0031] Figures 3A to 3N A highly simplified schematic diagram of a ground milling machine is shown, in which the rear roller flaps are in different positions when the ground milling machine is started and operated. Detailed Implementation

[0032] Figure 1A side view of a ground milling machine according to the invention is shown, which is described in detail in EP 2 977 514 B1. The ground milling machine has a chassis 1, which includes two front traveling mechanisms 2 and two rear traveling mechanisms 3. In this embodiment, the traveling mechanisms 2 and 3 are wheels. A lifting column 4 is fastened to each traveling mechanism 2 and 3 and carries a machine frame 5, allowing the height of the machine frame relative to the ground 6 to be adjusted. A driver's platform 7 is located on the machine frame 5, in front of the front traveling mechanisms 2 in the working direction 11. A roller housing 8 is arranged on the machine frame 5 between the traveling mechanisms, the roller housing 8 being open downwards, and a milling / mixing roller 9 is located in the roller housing 8. The rotation direction of the milling / mixing roller is marked by arrow 10. The roller housing 8 has a roller flap 12 at the front in the working direction 11 and a roller flap 13 at the rear in the working direction, the roller flaps 12 and 13 being pivotable about a pivot axis 14' or 14 extending transversely to the longitudinal direction of the machine frame. The roller housing is closed at the side by side members 15 extending in the longitudinal direction, the side members 15 being only... Figure 1 The outline is roughly shown in the middle.

[0033] To adjust the height of the milling / mixing roller 9, the ground milling machine has a milling / mixing roller adjustment device 16. In this embodiment, the milling / mixing roller adjustment device 16 includes a piston-cylinder assembly 17 having a piston 17A and a cylinder 17B. By actuating the piston 17A of the piston-cylinder assembly 17 of the milling / mixing roller adjustment device 16, the height of the milling / mixing roller 9 relative to the machine frame 5 or the ground 6 can be adjusted, wherein the axis of the milling / mixing roller moves in a circular path. Adjustment of the height of the milling / mixing roller 9 relative to the ground 6 is also possible by retracting or extending the lifting column 4. To control the piston-cylinder assembly 17 of the milling / mixing roller adjustment device 16, a control device 18 is provided. Figure 1 (Not shown in the image), which includes a control and computing unit 18A, which can be a separate control and computing unit, or can be a ground milling machine ( Figure 2 Components of the central control and computing device (not shown).

[0034] The front and rear roller flap adjustment devices 19 are configured to adjust the positions of the front and rear roller flaps 12 and 13 in the working direction. In the embodiments described below, only the rear roller flaps are considered.

[0035] The roller tilting device 19 of the rear roller tilting plate 13 has at least one actuator acting on the roller tilting plate. In this embodiment, the actuator is a piston-cylinder device 20, whose piston 20A is pivotally attached to the machine frame 5 and whose cylinder 20B is pivotally attached to the rear roller tilting plate 13.

[0036] By moving the piston 20A of the piston cylinder assembly 20 to a specific position (hereinafter referred to as a), or by retracting or extending the piston 20A from its initial position by a predetermined distance (hereinafter referred to as Δa), the rear roller flap 13 can pivot upward or downward about a pivot axis 14 extending transversely to the working direction to a predetermined pivot position α or pivot through a predetermined pivot angle Δα, which is related to the distance Δa, so that the lower edge 13A of the roller flap 13 can be raised or lowered relative to the ground 6. Figure 3A ).

[0037] To control the actuator, the roller tilting device 19 has a control device 21 ( Figure 1 (Not shown in the image), the control device 21 includes a control and calculation unit 21A, which can be a separate control and calculation unit or can be a ground milling machine ( Figure 2 Components of the central control and computing device.

[0038] The control and computing unit 21A of the control device 21 of the roller tilting device 19 may have, for example, a general-purpose processor, a digital signal processor (DSP) for continuous processing of digital signals, a microprocessor, an application-specific integrated circuit (ASIC), an integrated circuit composed of logic elements (FPGA), or other integrated circuits (ICs), or hardware components, to control the actuator. The data processing program (software) can run on the hardware components. Combinations of different components are also possible.

[0039] The roller tilting device 19 also includes other components known to those skilled in the art, particularly hydraulic components such as hydraulic pumps, hydraulic valves, and hydraulic lines.

[0040] In addition, the ground milling machine has a drive unit (not shown) for hydraulic components (such as hydraulic pumps or hydraulic motors), for example for driving the walking mechanism.

[0041] The following reference Figures 3A to 3N The control of the rear roller tilting plate 13 by the control device 21 via the roller tilting plate adjustment device 19 is described in detail, wherein corresponding components are provided with the same reference numerals. First, the application of the milling / mixing roller 9 for initiating the milling operation is described.

[0042] To apply the milling / mixing roller 9, the machine operator moves the ground milling machine to the desired position with the milling / mixing roller 9 raised. In this position, the lifting column 4 is extended to its maximum extent and the milling / mixing roller 9 is moved to the upper position. Figure 3AThen the lifting column 4 retracts to a large extent and the milling / mixing roller 9 enters its contact position with the ground 6. This process is also known as scraping. In this position, the piston 20A of the piston cylinder assembly 20 is in the "a0" position, while the roller flap 13 is in the pivot position "α0". Figure 3B When the milling / mixing roller 9 contacts the ground 6, the milling / mixing roller adjusting device 16 performs zero-position adjustment. Therefore, further lowering of the milling / mixing roller, or the predetermined distance that the piston 17A of the piston cylinder device 17 of the milling / mixing roller adjusting device 16 moves, corresponds to the milling depth. It should be noted that the change in the length of the piston cylinder device does not necessarily correspond to a change in milling depth in a 1:1 ratio. Considering the geometry, the change in milling depth can be calculated from the stroke of the piston 17A. Through zero adjustment, a reference plane corresponding to the surface of the unmilled ground 6 is established. Therefore, the milling depth can be adjusted by the distance covered by the lowering of the milling / mixing roller 9 relative to the machine frame 5 or the ground surface, or by the movement of the piston 17A in or out, or it can be determined from the distance covered when lowering the milling / mixing roller or moving the piston. The distance traveled can be detected using a known distance sensor. The milling / mixing roller 9 is now lowered to the desired milling depth, thus initiating the milling process. Figure 3C In the lowered position, the rear roller flap 13 enters the floating position, in which the lower edge 13a of the roller flap rests on the ground 6 with a predetermined contact force, so that the roller housing 8 is closed at the rear (h=0). The hydraulic device used to achieve the floating position is prior art (DE 10 2004 012 382 B4).

[0043] Figure 2 A simplified hydraulic circuit diagram is shown for an embodiment of the piston cylinder assembly 20 used to achieve a floating position of the roller tilting device 19. In the floating position, to raise and lower the rear roller tilting device 13, the hydraulic valve 22 of the hydraulic unit (not shown in more detail) connects the upper and lower cylinder chambers of the piston cylinder assembly 20 to a hydraulic tank (not shown) via hydraulic lines 23, 24 connected to the cylinder connectors, so that system pressure is not applied to the chambers. The hydraulic valve 22 is a four-way three-position valve (4 / 3 Wegeventil). For simplicity, the hydraulic lines leading to the hydraulic valve 22 are not shown in the diagram. Figure 2 As shown in the diagram. Since no specific hydraulic pressure acts on the cylinder, piston 20A can move within cylinder 20B, causing roller flap 13 to move downwards due to its gravity. By switching hydraulic valve 22, system pressure can be applied to one or another hydraulic line 23, 24 (pressure line), or one or another hydraulic line can be connected to the tank (tank line), causing piston 20A to move upwards or downwards.

[0044] The roller tilting device 19 can also be designed such that the roller tilting plate 13 does not rest on the ground under its own weight, but rather loads or releases the load using an additional contact force. If, in the floating position, the two chambers are subjected to pressures that preferably do not correspond to the system pressure, then, for example, if the two cylinder chambers have the same pressure, the downward movement of the roller tilting plate can be supported by a corresponding design of the effective contact surfaces of the cylinders.

[0045] In principle, the present invention can also be implemented by a roller tilting plate adjusting device 19 having a single-acting piston cylinder device. The single-acting piston cylinder device is characterized in that it can only operate in one direction. The roller tilting plate adjusting device 19 only needs to be able to raise the roller tilting plate. The floating position is achieved such that when no hydraulic pressure is applied to the piston cylinder device, the roller tilting plate sinks along the direction of gravity under its own weight.

[0046] When the ground milling machine is started and moves in the working direction 11, the mixing chamber of the roller housing 8 is filled with the milled material, which is deposited behind the milling / mixing roller 9 in the working direction.

[0047] Figure 3C and Figure 3D This shows the application of the milling / mixing roller 9 ( Figure 3C ) and after the milling machine has been started ( Figure 3D The roller housing 8. After application, the piston 20A of the piston cylinder assembly 20 is in the "a0" position, and the roller flap 13 is in the pivot position "α0", such that the lower edge 13A of the rear roller flap 13 is at zero height (h=0) above the unmilled ground surface 6 forming the reference plane. It can be seen that the mixing chamber is increasingly filled with the milled material 25, in which a specific rest angle is established according to the forward speed and material characteristics. Figure 3D The diagram shows the time point at which material 25 reaches the rear roller flap 13. Because the rear roller flap 13 is in a floating position, it can make way if the mixing chamber continues to be filled with material as the ground milling machine advances (a1, α1 or Δa1, Δα1), such that... Figure 3E As indicated in the document. The purpose is to establish... Figure 3F The equilibrium state between the milled material and the deposited material is shown, wherein the lower edge 13A of the rear roller flap 13 in the floating position rests on the material 25 thrown to the rear, and the roller housing 8 is closed at the rear, and the material is pulled out from the rear roller flap.

[0048] However, in practice, it has been shown that after the milling / mixing roller 9 has been applied, material can accumulate in the roller housing 8 as the ground milling machine advances, because the floating milling / mixing roller exerts considerable counter-pressure on the milled material. With material accumulation, the mixing ratio of material and binder can no longer meet specifications, and the drive power required to drive the milling / mixing roller increases. In the worst case, the accumulated material can severely impede the movement of the milling / mixing roller, causing the internal combustion engine of the drive unit to stall. The same problem occurs when the milling depth increases during milling operations.

[0049] The control device 21 of the roller tilting device 19 or the central control and calculation device of the ground milling machine (which may include the control and calculation unit of the control device of the roller tilting device) is configured in such a way that the following method steps are performed. The roller tilting device 19 provides a roller tilting position correction mode, which can be activated manually or automatically and includes at least one roller tilting position correction cycle.

[0050] To manually activate the roller tilting plate position correction mode, the control device 21 of the roller tilting plate adjustment device 19 has an operating element 26 ( Figure 2 The machine operator can operate the operating element 26 after the ground milling machine has been started or after a larger milling depth has been set during the milling operation. When the operating element 26 is operated, a control signal is generated, which is received by the control and calculation unit 21A of the control device 21 of the roller tilting device 19.

[0051] After receiving the control signal, the roller tilting plate position correction mode is switched on, thereby executing the first roller tilting plate position correction cycle. In the roller tilting plate position correction cycle, the control device switches the floating position of the rear roller tilting plate 13 to disconnect and controls the piston cylinder device 20 of the roller tilting plate adjustment device in such a way that the rear roller tilting plate 13 rotates at a first pivot angle α1. Figure 3E The rear roller flap 13 pivots away from the first pivot position (floating position), in which the lower edge 13A of the rear roller flap 13 rests floatingly on the milled material 25, wherein the height of the lower edge above the ground is h. 11 And it pivots upward through an angle Δα2, leaving the pivot position "α1" and entering the second pivot position with a second pivot angle α2 (at a height of h above the ground). 21 () Figure 3G In response, the piston 20A of the piston cylinder assembly 20 is pulled back by a preset distance Δa2, which can be measured by the distance sensor 28. Figure 2 ) can be measured from memory 27 ( Figure 2The distance a2 or Δa2 is read, which is a variable related to the pivot position (specifically, the height of the lower edge 13a of the roller flap 13). The memory 27 stores pivot angles or distances related to the pivot angles suitable for different milling depths to be set. Next, in the second step, the floating position of the rear roller flap 13 is switched again, so that the rear roller flap 13 is at a third pivot angle α3 (height above ground = h). 31 The third pivot position, in which the lower edge of the roller plate rests on the milled material. Figure 3H Piston 20A moves from position “a2” to position “a3”, or the piston extends by Δa3.

[0052] Figure 3G This shows that after the floating position has been cancelled, the rear roller flap 13 has moved from the first pivot position (h). 11 () Figure 3E ) rise to the second pivot position (h 21 ) time point, and Figure 3H This shows that after resetting to the floating position, the rear roller flap 13 is already in the third pivot position (h). 31 The time point of the milling process. Since the milled material flows in simultaneously, it can be seen that the third pivot position ( Figure 3H To a large extent, it corresponds to the second pivot position ( Figure 3G In this embodiment, h 31 ≈h 21 In this case, h 31 Greater than h 11 .

[0053] The automatic activation of the roller tilting plate position correction mode is described as follows. When the ground milling machine starts and the milling depth is greater than zero, the drive unit generates a control signal, which is received by the control and calculation unit 21A of the control device 21 of the roller tilting plate adjustment device 19. After receiving the control signal, the timer 21AA or the odometer 21AB is started. The timer and / or odometer can be components of the roller tilting plate adjustment device 19, especially its control and calculation unit 21A, or can be other components of the ground milling machine. When the predetermined time interval has expired or the ground milling machine has covered the predetermined distance, the control device 21 switches to the off floating position in the first step and moves the rear roller tilting plate 13 from the first pivot position ( Figure 3E Pivot upwards to the second pivot position ( Figure 3G Then, in the second step, the floating position is switched again, so that the rear roller flap 13 is in the third pivot position. Figure 3H ), wherein its lower edge 13A rests on the milled material 25.

[0054] When the milling / mixing roller adjustment device 16 generates a control signal, the roller flipper position correction mode is also automatically activated. The control signal sends a signal to the control and calculation unit 21A of the control device 21 of the roller flipper adjustment device 19 to notify that the milling / mixing roller adjustment device has increased the milling depth by a predetermined value during the milling operation.

[0055] if Figure 3F If the equilibrium shown has not yet been established, the rear roller 13 continues to exert considerable counter-pressure on the material, allowing it to continue accumulating. This applies to both initial situations and increasing milling depth. In this case, another roller position correction cycle is executed. The roller position correction cycle is executed until a position is determined. Figure 3F The equilibrium state shown has been established. The roller tilting position correction cycle in the roller tilting position correction mode includes a check routine.

[0056] To perform the inspection routine, in one embodiment, the control unit 21 of the roll tilting device 19 is configured such that the equilibrium state is inferred based on a comparison of the value of a variable associated with the third pivot position (distance Δa in this embodiment) with a threshold. Different thresholds can be defined to account for dynamic conditions; these thresholds can be stored in the memory 27 and can be read by the control and calculation unit 21A of the control unit 21 of the roll tilting device 19.

[0057] For this inspection, the control device detects the distance Δa3 traveled by the piston 20A of the piston cylinder device 20 of the roller tilting device 19 from the second pivot position to the third pivot position. Figure 3G , Figure 3H The distance Δa3 is measured when the floating position resets after a predetermined time interval or after the ground milling machine has covered a predetermined distance. For this purpose, a timer 21AA or odometer 21AB is activated for a specified predetermined time interval. However, other timers or odometers may also be provided. The time interval or distance used for checking may differ from the time interval or distance used for automatic activation of the roll turner position correction mode.

[0058] If the distance Δa3 is less than or equal to the threshold, i.e. Figure 3G and Figure 3H If the roller flap 13 shown does not fall back from the second pivot position by the minimum amount, a balanced state cannot be deduced, and the roller flap position correction cycle repeats. For this purpose, the control device 21 of the roller flap adjustment device 19 again controls its piston cylinder device 20 to perform the first and second steps described above. The floating position is switched off, and the rear roller flap 13 pivots upward away from the first pivot position ( Figure 3I Entering the second pivot position ( Figure 3J (h) 22In the first pivot position, the rear roller flap rests floatingly on the milled material 25 (h) 12 For this purpose, the piston 20A of the piston cylinder device 20 of the roller tilting device 19 retracts by a predetermined distance Δa. Then, the floating position is switched on again, causing the rear roller tilting device 13 to fall into the third pivot position (h). 32 () Figure 3K ).

[0059] The control device re-detects the distance Δa that the piston 20A of the piston cylinder assembly 20 of the roller tilting device 19 has retracted during its pivoting from the second pivoting position to the third pivoting position. Then the above-described inspection routine is executed again.

[0060] If the distance Δa is less than or equal to the threshold, i.e. Figures 3I to 3K If the roller flap 13 shown does not fall back from the second pivot position by the minimum amount, an equilibrium state cannot be inferred, and the check cycle is repeated. On the other hand, if the distance Δa is greater than the threshold, i.e., the roller flap has fallen back, an equilibrium state is inferred. The check cycle is repeated until an equilibrium state is established. Figure 3F The equilibrium state shown indicates that the distance Δa has been determined to be greater than the threshold.

[0061] Figure 3L The first pivot position (h) of another roller flap position correction mode is shown. 13 ), Figure 3M The second pivot position (h) is shown. 23 ),as well as Figure 3N The third pivot position (h) is shown. 33 It can be seen that the roller flap 13 falls back by a relatively large amount, where the distance Δa is greater than the threshold, thus the equilibrium state (h) can be inferred. 33 <h 23 Then, the roll tilting plate position correction mode is disabled. However, in an alternative embodiment, if the distance Δa is determined to be greater than the threshold only once, the roll tilting plate position correction mode is not yet disabled. Instead, another check loop is executed to check whether the roll tilting plate falls back by an amount greater than the threshold again.

[0062] In a particularly preferred embodiment, based on the variable value associated with the third pivot position ( Figure 3H ) and variable values ​​related to the first pivot position ( Figure 3EThe balance state is inferred by comparison. In this embodiment, the variable value associated with the third pivot position is distance a3 or Δa3, and the variable value associated with the first pivot position is distance a1 or Δa1. If the balance state has been determined at least once, the check routine is terminated, and the roller tilting plate position correction mode is deactivated. Otherwise, another check cycle is executed. In this embodiment, the control device 21 of the roller tilting plate adjustment device 19 is configured such that the distance Δa (hereinafter referred to as ΔA) by which the piston 20A of the piston cylinder device 20 of the roller tilting plate adjustment device 19 retracts to raise the rear roller tilting plate 13 is compared with the distance Δa (hereinafter referred to as ΔB) by which the piston of the piston cylinder device extends when the rear roller tilting plate falls back. That is, the amount by which the roller tilting plate is raised is compared with the amount by which the milling / mixing roller falls back. When the distance ΔB is less than the distance ΔA, the control device executes another roller tilting plate position correction mode. When it is determined that the distance ΔB is equal to or greater than the distance ΔA, the roller tilting plate position correction mode is deactivated. Therefore, the roller flap remains in a floating position and is pulled to float above the milled ground surface. In an alternative embodiment, the roller flap position correction mode is deactivated only when distance ΔB is equal to or greater than distance ΔA in at least two consecutive roller flap position correction cycles.

[0063] Figure 3G and Figure 3J The rear roller flap 13 is shown in the second pivot position, and Figure 3H and Figure 3K This shows that the roller flap has pivoted upwards relative to the first pivot position to the third pivot position (h). 31 h 11 or h 32 h 12 Because material has already flowed in simultaneously, that is, after a predetermined time interval or after covering a predetermined distance, the roller flap has lowered by an amount less than the roller flap's rise, which is determined by comparing the recorded distances ΔA and ΔB. At the third pivot position ( Figure 3H or Figure 3K The lower edge 13A of the roller flap 13 is higher than before it was raised ( Figure 3E or Figure 3I The height of the material flow is not yet balanced, thus preventing the execution of further inspection cycles.

[0064] Figures 3L to 3N Indicates the position at the third pivot point ( Figure 3N The height of the lower edge 13A of the rear roller flap 13 approximately corresponds to the position of the first pivot ( Figure 3L The height of the roller flap is determined to establish the equilibrium state.

[0065] The control device 21 of the roller tilting adjustment device 19 can also be configured such that the roller tilting position correction mode can only be automatically activated again when the milling / mixing roller has returned to the zero position. This prevents the roller tilting position correction mode from being automatically activated after the ground milling machine has only been temporarily stopped.

Claims

1. A ground milling machine having a machine frame (5) on which milling / mixing rollers (9) are arranged, the milling / mixing rollers (9) being arranged in a roller housing (8) having an opening at the bottom and having a roller flap (13) at the rear in the working direction, the roller flap (13) being pivotable about a pivot axis (14) extending transversely to the longitudinal direction of the machine frame, wherein a roller flap adjustment device (19) is provided, the roller flap adjustment device (19) having at least one actuator for pivoting the rear roller flap and a control device (21) for controlling the at least one actuator such that the height of the lower edge (13A) of the rear roller flap (13) relative to the ground (6) is adjustable, the control device (21) of the roller flap adjustment device (19) being designed such that the at least one actuator is controlled to cause the rear roller flap in a floating position to rest on the ground with a predetermined contact force; Its features are, The roller tilting device (19) provides an activatable roller tilting position correction mode, which includes at least one roller tilting position correction cycle, wherein the control device (21) of the roller tilting device (19) is designed such that, in the at least one roller tilting position correction cycle, in a first step, the floating position of the rear roller tilting device (13) is canceled and the rear roller tilting device is pivoted upward away from the first pivoting position and into the second pivoting position, such that the lower edge (13A) of the rear roller tilting device (13) is raised, and in a second step, after the rear roller tilting device has been in the second pivoting position, the floating position is set again, such that the rear roller tilting device is in the third pivoting position, in which the lower edge of the rear roller tilting device rests on the ground (6).

2. A ground milling machine according to claim 1, characterized in that The at least one roll tilting position correction cycle includes a check routine, wherein the control device (21) of the roll tilting adjustment device (19) is designed such that a variable associated with the third pivoting position is compared with a threshold, or a variable associated with the third pivoting position is compared with a variable associated with the first pivoting position, wherein the roll tilting position correction mode is deactivated based on the comparison of the value of the variable associated with the third pivoting position with the threshold, or based on the comparison of the value of the variable associated with the third pivoting position with the value of the variable associated with the first pivoting position.

3. A ground milling machine according to claim 2, characterized in that, The variable associated with the first pivot position and the third pivot position is the variable associated with the height (h) of the lower edge (13A) of the rear roller flap (13). The control device (21) of the roller flap adjustment device (19) is designed such that the roller flap position correction cycle is executed until it is determined at least once that the height (h) of the lower edge (13A) of the rear roller flap (13) at the third pivot position is equal to or less than the height of the lower edge of the rear roller flap at the first pivot position.

4. A ground milling machine according to any one of claims 1 to 3, characterized in that, The at least one actuator of the roller flap adjusting device (19) is a piston cylinder device (20) acting on the roller flap, and for detecting variables associated with the first and / or third pivot position, a measuring unit is provided which detects the position of the piston (20A) of the piston cylinder device (20).

5. A ground milling machine according to claim 4, characterized in that The measuring unit is a distance sensor.

6. The ground milling machine according to any one of claims 1 to 3, characterized in that, The control device (21) of the roller flap adjusting device (19) is designed in such a way that after a predetermined time interval has elapsed or after a predetermined distance has been covered, after the floating position has been cancelled or after the rear roller flap (13) has been pivoted into the second pivot position, the floating position is set again in the second step.

7. The ground milling machine according to any one of claims 1 to 3, characterized in that, A memory (27) is provided in which, for different milling depths, the pivot angle of the rear roller flap (13) from the first pivot position into the second pivot position is stored, the control device (21) of the roller flap adjusting device (19) being designed in such a way that the pivot angle is read from the memory (27) depending on the set milling depth.

8. The ground milling machine according to any one of claims 1 to 3, characterized in that, The control device (21) of the roller flap adjusting device (19) has an operating element (26), the control device (21) being designed in such a way that the roller flap position correction mode is activated by operating the operating element (26).

9. The ground milling machine according to any one of claims 1 to 3, characterized in that, The control device (21) of the roller flap adjusting device (19) is designed in such a way that the roller flap position correction mode is activated when a predetermined distance has been covered after the start of the ground milling machine or when a predetermined time interval has elapsed after the start of the ground milling machine.

10. The ground milling machine according to any one of claims 1 to 3, characterized in that, The ground milling machine has a milling / mixing roller adjusting device (16) which is designed in such a way that the height of the milling / mixing roller (9) relative to the machine frame (5) can be adjusted, so that the milling depth can be changed, the control device (21) of the roller flap adjusting device (19) being designed in such a way that the roller flap position correction mode is activated when the milling / mixing roller adjusting device (16) has increased the milling depth by a predetermined value during a milling operation and after the increase in the milling depth has elapsed for a predetermined time interval or after the ground milling machine has covered a predetermined distance.

11. A ground milling machine according to any one of claims 1 to 3, characterized in that, The ground milling machine is a stabilizer or a recycling machine.

12. A method for operating a ground milling machine having a machine frame on which a milling / mixing roller is arranged, which is arranged in a roller housing which is open at the bottom and has a roller flap at the rear in the direction of travel, which roller flap can be pivoted about a pivot axis extending transversely to the longitudinal direction of the machine frame, so that the height of the lower edge of the rear roller flap relative to the ground is adjustable, the ground milling machine being operated in such a way that the rear roller flap in the floating position rests on the ground with a predetermined contact force; characterized in that activating a roller flap correction mode, which comprises at least one roller flap position correction cycle, wherein in the at least one roller flap position correction cycle, in a first step, the floating position of the rear roller flap is cancelled and the rear roller flap is pivoted upward from a first pivot position into a second pivot position, so that the lower edge of the rear roller flap is raised, and in a second step, after the rear roller flap has been in the second pivot position, the floating position is set again, so that the rear roller flap is in a third pivot position, in which the lower edge of the rear roller flap rests on the ground.

13. The method for operating a ground milling machine of claim 12, characterized in that, The at least one roller flap position correction cycle comprises a check routine, in which a variable related to the third pivot position is compared to a threshold value or a variable related to the third pivot position is compared to a value of a variable related to the first pivot position, wherein based on the comparison of the value of the variable related to the third pivot position to the threshold value or based on the comparison of the value of the variable related to the third pivot position to the value of the variable related to the first pivot position, the roller flap position correction mode is deactivated.

14. The method for operating a ground milling machine of claim 13, characterized in that, The variables related to the first pivot position and to the third pivot position are variables related to the height of the lower edge of the rear roller flap, and the roller flap position correction cycle is executed until it is determined at least once that the height (h) of the lower edge (13A) of the rear roller flap (13) in the third pivot position is equal to or less than the height of the lower edge of the rear roller flap in the first pivot position.

15. The method for operating a ground milling machine according to any one of claims 12 to 14, characterized in that, The floating position is set again in the second step after a predetermined time interval has elapsed or after a predetermined distance has been covered, after the floating position has been cancelled or after the rear roller flap has been pivoted into the third pivot position.

16. The method for operating a ground milling machine according to any one of claims 12 to 14, characterized in that, The pivot angle, by which the rear roller flap is pivoted out of the first pivot position and into the second pivot position, is read from a memory, in which pivot angles adapted to different milling depths are stored, depending on the set milling depth.

17. The method for operating a ground milling machine according to any one of claims 12 to 14, characterized in that, The roller flap position correction mode is activated when the ground milling machine has covered a predetermined distance after a start or a predetermined time interval has elapsed after the start.

18. The method for operating a ground milling machine according to any one of claims 12 to 14, characterized in that, The roller flap position correction mode is activated when the milling depth has been increased by a predetermined value during a milling operation and after the increase of the milling depth has elapsed a predetermined time interval or the ground milling machine has covered a predetermined distance.

19. The method for operating a ground milling machine according to any one of claims 12 to 14, characterized in that, The ground milling machine is a stabilizer or a recycler. The ground milling machine is a stabilizer or a recycler.

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