BE1025031A1 - Arrangement for detecting the degree of wear of chopping blades of a chopper drum of a forage harvester - Google Patents

Abstract

An arrangement for detecting the degree of wear of chopping knives (144) of a chopper drum (36) of a forage harvester (10) comprises: an inductive sensor (152) inserted into or connected to a counterblade (102) and passing through a chopping knife (144) passing by Signal output, a mechanism for adjusting the counter-blade (102) relative to the enveloping circle of the cutterhead (36), and connected to the sensor (152) evaluation device (70), which is configured based on the signal of the sensor (152) information regarding the orientation of the counter-blade (102) relative to the enveloping circle of the cutterhead (36) to generate.

Description

(30) Priority information:

30/01/2017 DE 102017201423.7 (71) Applicant:

DEERE & COMPANY IL 61265, MOLINE United States (72) Inventor:

BOHRER Stefan 66606 ST. WENDEL Germany

MUNICH Philipp

67663 KAISERSLAUTERN Germany

STONE Matthias

66424 HOMBURG Germany

COOK Rolf

66540 NEUNKIRCHEN Germany (54) Arrangement for the detection of the degree of wear of chop knives of a chopper drum of a forage harvester (57) An arrangement for the detection of the degree of wear of chop knives (144) of a chopper drum (36) of a forage chopper (10) comprises: one in a shear bar (102) inserted or connected inductive sensor (152), which emits a signal when a chopping knife (144) passes by, a mechanism for adjusting the shearbar (102) relative to the enveloping circle of the chopper drum (36), and one connected to the sensor (152) Evaluation device (70), which is set up to generate information on the orientation of the shearbar (102) with respect to the enveloping circle of the chopper drum (36) based on the signal from the sensor (152).

BE2017 / 0156

Arrangement for the detection of the degree of wear of

Chopper blades of a forage harvester's chopper drum

The invention relates to an arrangement for detecting the degree of wear of chop knives of a chopper drum of a forage harvester and a forage harvester equipped therewith.

State of the art

Forage harvesters are used to plant or their

Pick up fruit stands from a field and cut them into small pieces. The plants standing in the field are usually cut off from the roots remaining in the soil by means of a suitable harvesting attachment and fed to a feed channel of the forage harvester. Alternatively, the plants can be cut off and swathed in a previous operation and picked up by means of a pick-up, or only the fruit stands are separated from the plants and conveyed into the feed channel. In the feed channel, the crop mat picked up by the header is pre-compacted by interacting pairs of pre-press rollers that feed the crop mat to a chopper drum, with a number of chopping knives distributed around its circumference (and possibly across its width). The chopping knives cut the crop into small pieces together with a shear bar. The chopped crop (and in particular corn kernels contained therein) is optionally further chopped by means of a post-processing device, conveyed into a discharge chute by means of a post-accelerator and loaded onto a transport vehicle. The chopped crop is used in particular as feed for cattle or for biogas production.

When cutting the crop, in addition to the sharpness of the chopper knives, the distance between the cutting edge of the chopper knives and the shear bar is of great importance in order to achieve a good cutting result in an energy-saving manner. To

BE2017 / 0156 the chopper knives are subjected to a grinding process after their first assembly and also later from time to time, in which a grindstone interacts with the rotating chopper drum. This then ensures that all cutting edges are sharp and are at least approximately the same distance from the axis of rotation of the chopper drum for all chopper knives. The position of the shear bar is usually set automatically.

DE 10 2011 005 317 A1 describes a measuring system for determining the wear state of chop knives of a chopper drum of a forage harvester. The measuring system is based on an inductive sensor built into the shear bar, which detects the magnetic field that changes as the chopper knife passes by, which induces a voltage in the sensor. The sharpness of the chopper knives and the distance to the shear bar are used to draw conclusions based on the time course of the electrical voltage detected by the sensor. As a result, a grinding process and / or a shear bar position setting process can be triggered automatically if required.

A certain amount of material is removed from the chopping knives during each grinding process. The chopper knives become shorter and shorter over time. While this can be compensated for by repositioning the shear bar, so that the actual cutting process is possible even with partially worn chopping knives, worn chopping knives only protrude slightly beyond the knife holder, which worsens their air delivery effect. As a result, the function of the chopper drum gradually deteriorates because it can only convey a little air from the inlet of the feed channel to the rear of the discharge chute. In addition, the chopping knives will eventually become so worn that they can no longer be sharpened.

In the state of the art, the operator must therefore check from time to time whether the chopping knives are worn to such an extent

BE2017 / 0156 are that they have to be adjusted. In this case, the chopping knives are unscrewed, pulled forward and finally screwed back on again to restore the air delivery effect. If the chopping knives are completely worn out, they must be replaced. This manual control is prone to errors and can be avoided by inexperienced operators, which can lead to poor functioning of the forage harvester. Although it has been proposed to detect the hard material layer of the chopper knives by means of a sensor which can detect physical properties of the hard material layer (DE 10 2009 047 584 A1) in order to determine the state of wear of the chopper knives, such sensors are currently not commercially available. The position of the shearbar moves when the chopping knives wear, also gradually inwards, in the direction of the axis of rotation of the chopper drum, but the sensors used in the prior art to detect the position of the shearbar are highly precise, but only designed to detect relative positions ( DE 10 2004 016 089 A1), which is why knock sensors are usually used when setting the shear bar to detect contact between the shear bar and chopper knives. These sensors are therefore not suitable for detecting the enveloping circle diameter of the chopper drum and thus the state of wear of the chopper knives.

Object of the invention

The object on which the invention is based is seen in the provision of an automatically operating arrangement for detecting the degree of wear of chop knives of a chopper drum of a forage harvester, which does not have the mentioned disadvantages or has them to a reduced extent and is capable of detecting the degree of wear of the chopper knives .

solution

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According to the invention, this object is achieved by the teaching of claims 1 and 5, features which are listed in the further claims which further develop the solution in an advantageous manner.

An arrangement for recognizing the degree of wear of chop knives of a chopper drum of a forage harvester comprises an inductive sensor inserted in or connected to a shearbar, which emits a signal when a chopper knife passes, a mechanism for adjusting the shearbar with respect to the enveloping circle of the chopper drum, which is set up. to adjust the shear bar on a non-radial path opposite the chopper drum, and an evaluation device connected to the sensor, which is set up to generate information regarding the orientation of the shear bar with respect to the enveloping circle of the chopper drum based on the signal of the sensor, and an information signal therefrom to produce the degree of wear of the chopping knives.

In other words, the counter-cutter is not exactly radially displaced relative to the chopper drum by the mechanism for adjusting the counter-cutter, but is moved on a non-radial path, which can be circular, for example. This changes the orientation of the shearbar with respect to the chopper drum when the shearbar is gradually moved closer to the fulcrum of the chopper drum as the knives wear out. This change in orientation is detected by the inductive sensor inserted into the shear bar, which detects the chopping knife passing by, because the steepness of the leading and trailing edges of the signal generated by the chopping knife passing by will change with the orientation of the shear bar. An evaluation device evaluates the signal and generates an information signal regarding the degree of wear of the chopping knives, which can be displayed to an operator. The operator can thus, if necessary, i.e. when the chopping knives are worn out sufficiently and theirs

BE2017 / 0156

Air scoop effect is no longer good enough, either replace the chopping knives or loosen them, pull them further outwards and fix them again.

In particular, the shearbar can be rotatable about a pivot point with respect to the enveloping circle of the chopping drum.

The evaluation device can be operable to calculate the angle of the shear bar around the pivot point on the basis of the time course of the sensor signal generated by a passing knife and, based on the angle of the shear bar, calculate the diameter of the enveloping circle of the chopper drum and the length of the chopper knife with which the latter their knife holders protrude to calculate.

The evaluation device can be operable to send an indication signal to an operator via an operator interface if the length of the chopper knives is below a threshold value.

Embodiment

In the drawings, an embodiment of the invention described below is shown. It shows:

1 is a side view of a self-propelled forage harvester,

Fig. 2 is a schematic representation of the shear bar of the forage harvester of Figure 2 with its adjustment device and an evaluation device which is used to determine the degree of wear of the chopper knife, and

3a and 3b examples of signals from the sensor depending on the degree of wear of the chopping knife.

BE2017 / 0156

1 shows a self-propelled forage harvester 10 in a schematic side view. The forage harvester 10 is built on a frame 12 which is supported by front driven wheels 14 and steerable rear wheels 16. The forage harvester 10 is operated from a driver's cab 18, from which a header 20 in the form of a pickup can be seen. By means of the header 20 harvested crop, z. B. grass or the like is fed via a feed conveyor 22 with pre-press rollers, which are arranged within a feed housing 24 on the front of the forage harvester 10, a chopper drum 26 arranged below the driver's cab 18, which chops it into small pieces in cooperation with a shearbar 102 and it gives up a conveyor 28. A grinding device 100 is used, if necessary, to sharpen the chopper blades 144. The material leaves the harvesting machine 10 to a transport vehicle traveling alongside via an ejection elbow 30 which can be rotated about an approximately vertical axis and adjustable in inclination. In the following, directional information such as the side, bottom and above, on the forward direction V of the harvesting machine 10, which runs to the right in FIG. 1.

The chopping drum 26 is driven starting from a pulley 48, which is connected to an internal combustion engine (not shown) via an angular gear, via a drive belt 50, which has a pulley 54 for driving the chopping drum 26 and a pulley 52 for driving the conveying device 28. A grinding device 100 is used to grind the chopper knives of the chopper drum 26. In addition, a metal detector 108 is provided in the lower, front pre-press roller, which may be used to quickly stop the feed conveyor 22, and an operator input device 98 coupled to a controller 70 in the driver's cab 18.

FIG. 2 shows the chopper drum 36 and the shear bar 102 in an enlarged view. The chopper drum 36 comprises a drum casing 72, which extends over support disks 74 and

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Stub axles with pivot bearings 76 is connected. Instead of the closed drum casing 72 shown, an open chopping drum 36 could also be used. Knife holders 146 are distributed around the circumference of the chopper drum 36 (and preferably over its width), to which the individual chopper knives 144 are each fastened by a plurality of screws 150. Pressure plates 148 are arranged between the heads of the screws 150 and the chopper blades 144. The threads of the screws 150 interact with threads in the knife holders or thread strips inserted transversely therein.

The shear bar 102 is rotatably mounted about an axis of rotation 156 which is located below the rotary bearing 76 of the chopper drum 36. At both lateral ends of the shear bar 102, a lever arm 154 is attached at one end to the axis of rotation 156 and at the other end to the shear bar 102. An adjustment drive 158 assigned to each lever arm 154 or to one end of the shear bar 102 serves to adjust the shear bar 102. The shear bar 102 can additionally be supported on the frame 12 by a bendable sheet metal (not shown), as described in DE 196 33 290 C2, the disclosure of which is incorporated into the present documents by reference.

An inductive sensor 152 is integrated or connected to the shear bar 102, which is connected to an evaluation device 70, which in turn is coupled to an operator interface 98. The inductive sensor can be designed in accordance with DE 10 2011 005 317 A1, the disclosure of which is incorporated into the present documents by reference.

The sensor 152 can be designed, for example, as a coil that is supplied with a high-frequency alternating current, for example in the kHz or MHz range, by an oscillator. If a (usually ferromagnetic) chopping knife 144 passes the shearbar 102 and thus the sensor 152,

BE2017 / 0156 the inductance of the coil changes, which changes the amplitude of the AC voltage applied to the coil. This amplitude is detected and evaluated by means of a detector (e.g. rectifier), which can be evaluated by an evaluation circuit integrated in the housing of the sensor 152 or in the evaluation device 70 or by a separate evaluation circuit. The sensor 152 accordingly provides a continuous idle or background signal (if no chopper knife 144 is coming by), which is interrupted by a chopper knife 144 as it passes by negative or positive impulses, as shown in FIGS. 3a and 3b.

The signal of the inductive sensor 152 changes depending on the respective temperature - even if other boundary conditions remain the same. These influences of the temperature change can lead to relevant points of the signal of the sensor 152 showing a change, although the real measurement objects (sharpness of the chopper blades 144 and their distance from the shear bar 102) have not changed or have not changed to the extent that the change in signal is displayed. A practical example is that the calculated cut gap values show a significantly faster (than the actual) growth when the forage harvester 10 and the shear bar 102 warm up after the start of the harvest in the morning. Analogously, these values can drop again when the forage harvester 10 and the shear bar 102 cool down. In principle, this behavior can also occur in the opposite way - falling values when heating and increasing values when cooling.

In order to compensate for this temperature drift, the evaluation circuit can take into account that the temperature-related signal changes act both on the signal dip when the chopper blade 144 passes as well as on the idle signal between two impulses caused by the chopper knife. The open circuit voltage of the sensor 152 is influenced only by the temperature only from the installation location of the sensor 152 in the shear bar 102. This does not change during a harvest day. In addition, it should be mentioned that the wear of the shear bar 102 also

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Predamping sensor 152 changes. However, it can be assumed that this process is much slower than the change in sensor temperature and can therefore be neglected. For temperature compensation, the procedure is such that as soon as (after an initial calibration of the sensor 152, in which the open circuit voltage is recorded and a value representing it is stored by the evaluation circuit) changes in the open circuit voltage are recognized over the period of use, these changes to correct the run-by the chopping knife 144 arising pulses can be used.

After all of this, the following mode of operation results: When a chopping knife 144 passes by, the sensor 152 generates an electrical signal due to the then changing magnetic field, which is fed to the evaluation device 70. If, after a certain operating time of the chopper drum 36, the chopper knives 144 become dull, the operator or an automatic system based on the signals from the sensor 152, on the basis of which the evaluation device 70 evaluates the sharpness of the chopper knives 144, will activate the grinding device 100. Since the envelope circle of the chopper blades 144 inevitably becomes smaller, the grinding process will be followed by a readjustment of the shear bar 102 in order to set the gap between the envelope circle of the chopper blades 144 and the shear bar 102 to a desired, relatively small value, for which purpose the evaluation device Signals of the sensor 152 can fall back in order to control the adjustment drive 158.

The adjustment of the shear bar 102, which can also be carried out independently of a grinding operation, has the consequence that the angle of the shear bar 102 with respect to the envelope circle of the chopper blades 144 changes, as can be seen in FIG. 2 from the dashed lines of the shear bar 102. This also changes the angle between the shearbar 102 and the chopper blade 144, which leads to changing slopes of the edges of the signals from the sensor 152 as the edges approach and move away

BE2017 / 0156 and trailing edges of the chopping knife 144 leads, as is shown schematically in FIG. 3a for the continuous shearbar 102 of FIG. 2 and in FIG. 3b for the shearbar shown in dashed lines in FIG. The falling flank that arises when the chopper knife 144 approaches is much flatter in FIG. 3a than in FIG. 3b, while the rising flank that arises when the chopper knife 144 runs away is much steeper in FIG. 3a than in FIG. 3b.

The evaluation device 70 is programmed to recognize on the basis of the steepness of one or both flanks what the angle of the shearbar 102 is about the axis of rotation 156. This angle is a measure of how much the chopper blades 144 are worn, i.e. Protrude beyond the front edge of the knife holder 146 in the direction of rotation. If the chopper blade 144 is worn out more than a predefined value or can be entered by the operator into the operator input device 98, the evaluation device 70 generates a corresponding message by the operator input device 98. The degree of wear of the chopper knife 144 can also be continuously displayed there. If necessary, the operator can thus replace the chopper blades 144 or loosen the screws 150 and move the chopper blades 144 forward by a defined length in the direction of rotation of the chopper drum 36 and then tighten the screws 150 again.

The automatic monitoring of the degree of wear of the chopper blades 144 makes it unnecessary for the operator to monitor it himself by inspecting the chopper drum 36.

BE2017 / 0156

Claims (5)

PATENT CLAIMS 1. An arrangement for detecting the degree of wear of chop knives (144) of a chopper drum (36) of a forage harvester (10), comprising: an inductive sensor (152) inserted into or connected to a shear bar (102), which emits a signal when a chopping knife (144) passes by, a mechanism for adjusting the shear bar (102) relative to the enveloping circle of the chopper drum (36) is to adjust the shear bar (102) on a non-radial path opposite the chopper drum (36), and an evaluation device (70) connected to the sensor (152), which is set up, provides information based on the signal from the sensor (152) with regard to the orientation of the shearbar (102) with respect to the enveloping circle of the chopper drum (36) and to generate an indication signal with regard to the degree of wear of the chopper knives (144). 2. Arrangement according to claim 1, wherein the shearbar (102) is rotatable relative to the enveloping circle of the chopper drum (36) about a pivot point (156). 3. Arrangement according to claim 2, wherein the evaluation device (70) is operable to calculate the angle of the shear bar (102) around the pivot point (156) on the basis of the time profile of the signal of the sensor (152) generated by a passing knife and using the Angle of the shear bar (102) to calculate the diameter of the enveloping circle of the chopper drum (36) and the length of the chopper knives (144) with which they protrude beyond their knife holder (146). 4. Arrangement according to claim 3, wherein the evaluation device (70) is operable via an operator interface (98) to a notification signal to an operator Give BE2017 / 0156 if the length of the chopper knife (144) is below a threshold. 5. forage harvester (10) with an arrangement according to one of the 5 preceding claims. BE2017 / 0156 ^{B £} 2O17 / _O1 56 <Ο cr> X—? X \ \ \ Cxi ίχ. CO Π · -. BE2017 / 0156 SUMMARY Arrangement for detecting the degree of wear of chop knives of a chopper drum of a forage harvester An arrangement for detecting the degree of wear of chop knives (144) of a chopper drum (36) of a forage harvester (10) comprises: an inductive sensor (152) inserted or connected to a shear bar (102), which emits a signal when a chopping knife (144) passes by, a mechanism for adjusting the shear bar (102) relative to the enveloping circle of the chopper drum (36), and one evaluation device (70) connected to the sensor (152), which is set up to use the signal from the sensor (152) to generate information regarding the orientation of the shearbar (102) with respect to the enveloping circle of the chopper drum (36).