Chopper blade of a field harvester and method for producing the same

Description

[0001] The invention relates to a chopper blade of a forage harvester. Furthermore, the invention relates to a method for producing a chopper blade of a forage harvester.

[0002] US 2014 / 311 114 A1 relates to a rotatable knife drum with knife holders for attaching knives, each knife holder comprising a front and a rear element and a knife connecting section. The rear element extends from the connecting section toward the rotational axis of the drum and has an extension element that extends circumferentially of the rotational axis in a direction opposite to the rotational direction of the drum. The front element extends from the connecting section toward the drum rotational axis and abuts the extension element of an adjacent knife holder arranged upstream in the rotational direction of the drum.

[0003] US 8 146 849 B2 discloses a chopper drum for a field chopper with a shaft on which support rings are mounted which are arranged next to one another in the axial direction and extend in the radial direction, wherein knife holders with chopper knives fastened thereto by first screws are arranged on the outer circumference of the support rings and wherein the first screws establish a connection between the knife holders which follow one another in the circumferential direction.

[0004] From DE 88 13 953 U1 a knife drum of a forage harvester with several drum bases mounted on an axle is known, wherein at least two adjacent drum bases are connected to one another by several knife holders evenly distributed around the circumference, each with a bearing surface that fully supports the knives, wherein each knife holder is assigned a material guiding surface, and each knife holder consists of a solid rolled profile with a machined material guiding surface.

[0005] EP 3 329 765 A1 discloses a chopper blade of a forage harvester having a base body and at least one crop guide element fastened to the base body. The base body has a fastening section for fastening the chopper blade to a chopper drum and a cutting section for the crop to be chopped, angled relative to the fastening section. The respective crop guide element is fastened to the fastening section of the base body and serves to guide chopped crop. A guide surface of the crop guide element has a curved contour. The curved contour of the crop guide element begins at a distance from a transition edge between the fastening section and the cutting section of the base body. The chopper blade known from EP 3 329 765 A1 is designed with a view to fastening the same to the chopper drum. This results in problems in guiding the chopped crop.There is a need for a chopping knife that optimally guides and guides the chopped crop.

[0006] Based on this, the present invention is based on the object of creating a novel chopper blade of a forage harvester and a method for producing the chopper blade.

[0007] This object is achieved by a chopping knife of a forage harvester according to claim 1.

[0008] According to the invention, the distance between the beginning of the guide surface of the respective material guide element and the transition edge between the fastening section and the cutting section of the base body is between 4 mm and 8 mm.

[0009] According to the invention, the guide surface of the respective material guiding element runs in a straight line with a length of between 4 mm and 8 mm in a first section of the material guiding element, which adjoins the beginning of the guide surface, wherein the first section of the respective material guiding element forms an angle of between 18° and 22° with the fastening section of the base body.

[0010] According to the invention, the first section of the respective material guiding element merges into a concavely curved second section, the radius of curvature of which is between 21 mm and 25 mm and which has a wrap angle of between 29° and 33°.

[0011] According to the invention, the second section of the respective material guiding element merges into a concavely curved third section, the radius of curvature of which is between 18 mm and 22 mm and which has a wrap angle of between 24° and 28°.

[0012] According to the invention, the third section of the respective material guiding element merges into a convexly curved fourth section.

[0013] According to the invention, the maximum height of the respective material guide element relative to the fastening section of the base body is between 24 mm and 30 mm. Preferably, the fourth section of the material guide element transitions into a fifth section, which defines the maximum height of the material guide element.

[0014] The distance between the beginning of the guide surface of each crop guide element and the transition edge of the base body, the length of the first section of the guide surface of each crop guide element, the radii of curvature and wrap angle of the concavely curved second and third sections of the guide surface of each crop guide element, the convexly curved fourth section, and the height of each crop guide element measured from the attachment section of the base body, all combine to ensure optimal guidance of the chopped crop. Optimal guidance and deflection of the chopped crop allows for energy savings in the conveying process, as deflecting the chopped crop requires little acceleration work.

[0015] Furthermore, the above combination of features redirects the crop in a defined area of one revolution of the chopper drum, thereby reducing the circulation of the crop in the area of the chopper drum.

[0016] The above combination of features is therefore optimized for flow and reduces the energy required for crop flow. Crop conveyance is highly efficient for a wide variety of crops, cutting lengths, and throughput rates.

[0017] Preferably, the fourth section of the respective crop guide element has a radius of curvature between 5 mm and 7 mm, with the fifth section of the respective crop guide element running parallel to the attachment section. This serves to further optimize crop guidance.

[0018] Preferably, the fifth section of the respective crop guide element transitions into a straight sixth section, which forms an angle of between 23° and 27° with the attachment section. This also allows for further optimization of crop guidance.

[0019] Preferably, the respective crop guide element is closed by sections adjoining the sixth section. This advantageously prevents crop material from accumulating on the rear knife edge. Deposits can lead to imbalance. This feature also serves to further optimize crop guidance.

[0020] The respective material guide element is a roll-profiled element. Roll-profiling involves surface hardening, which can provide increased hardness for the respective material guide element. This can reduce its susceptibility to wear.

[0021] Preferably, the first section, the second section, and the third section of the respective material guide element have a wear-resistant coating. This can also reduce the susceptibility of the respective material guide element to wear.

[0022] The method for manufacturing the chopping knife is defined in claim 10.

[0023] Preferred developments of the invention will become apparent from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being limited thereto, with reference to the drawings. In the drawings: Fig. 1 shows a cross-section through a chopping knife according to the invention; Fig. 2 shows the cross-section of the Fig. 1 with geometric sizes; Fig. 3 a section of Fig. 2 ; Fig. 4 the section of the Fig. 3 together with crop flow arrows; Fig. 5 the section of the Fig. 3 together with further crop flow arrows; Fig. 6 the section of the Fig. 3together with further crop flow arrows; Fig. 7 the section of the Fig. 3 together with further crop flow arrows; Fig. 8 another section of Fig. 2 ; and Fig. 9 another section from Fig. 2 .

[0024] Fig. 1 shows a cross-section through a chopping knife 10 according to the invention. The chopping knife 10 according to the invention has a base body 11 and at least one material guide element 15.

[0025] The base body 11 of the chopping knife 10 has a fastening section 12 for fastening the chopping knife 10 to a chopping drum (not shown) and a cutting section 13 angled relative to the fastening section 12 for cutting the crop to be chopped.

[0026] The cutting section 13 of the base body 11 of the chopping knife 10 is angled relative to the fastening section 12 of the base body 11.

[0027] Between the fastening section 12 and the cutting section 13 of the base body 11 of the chopping knife 10, a transition edge 14 in the form of a bending edge is formed.

[0028] As already explained, the chopping blade 10 can be attached to a chopping drum (not shown) via the attachment section 12. For this purpose, fastening elements (not shown), preferably designed as elongated holes, are inserted into the attachment section 12, via which the chopping blade 10, namely its base body 11, can be attached to the chopping drum.

[0029] At least one crop guide element 15 is attached to the fastening section 12 of the base body 11. The crop guide element 15 has a guide surface 16 for chopped crop material, with the guide surface 16 having a curved contour at least in sections. The guide surface 16 is concavely curved inward in sections.

[0030] The guide surface 16 of the material guide element 15 has a front edge 17, with which the guide surface 16 begins. This edge 17 of the guide surface 16 of the material guide element 15 has a distance a from the transition edge 14 between the fastening section 12 and the cutting section 13 of the base body 11.

[0031] According to the invention, the distance a between the beginning of the guide surface 16 of the material guide element 15, i.e. the edge 17, and the transition edge 14 between the fastening section 12 and the cutting section 13 of the base body 11 is between 4 mm and 8 mm, i.e. 6 mm ± 2 mm.

[0032] According to the invention, the guide surface 16 of the material guide element 15 runs in a straight line in a first section 18 adjoining the edge 17, specifically along a length b which is between 4 mm and 8 mm, i.e. 6 mm ± 2 mm.

[0033] This first section 18 of the material guiding element 15 forms an angle α between 18° and 22°, i.e. 20° ± 2°, with the fastening section 12 of the base body 11.

[0034] According to the invention, this first section 18 of the guide surface 16 of the material guide element 15 merges into a concavely curved second section 19, namely continuously and thus tangentially, wherein the second section 19 has a radius of curvature Rx between 21 mm and 25 mm, i.e. 23 mm ± 2 mm, and a wrap angle β between 29° and 33°, i.e. 31° ± 2°.

[0035] According to the invention, this second section 19 of the guide surface 16 of the material guide element 15 merges into a concavely curved third section 20, again continuously or tangentially, the concavely curved third section 20 having a radius of curvature Ry between 18 mm and 22 mm, i.e. 20 mm ± 2 mm, and a wrap angle γ between 24° and 28°, i.e. 26° ± 2°.

[0036] The radius of curvature Rx of the concavely curved second section 19 of the guide surface 16 of the material guiding element 15 is greater than the radius of curvature Ry of the concavely curved third section 20 of the guide surface 16 of the material guiding element.

[0037] Furthermore, the wrap angle β of the concavely curved second section 19 is greater than the wrap angle γ of the concavely curved third section 20.

[0038] According to the invention, the concavely curved third section 20 of the guide surface 16 of the material guiding element 15 merges into a convexly curved fourth section 21, wherein this fourth section 21 of the material guiding element 15 preferably merges into a fifth section 22, which preferably determines the maximum height c of the material guiding element 15 - measured from the fastening section 12 of the base body 11.

[0039] According to the invention, this maximum height c of the material guide element 15 is between 24 mm and 30 mm, i.e. 27 mm ± 3 mm.

[0040] The above parameters of the chopper blade 10 enable optimal crop flow guidance. The crop is guided with minimal acceleration work, which saves energy for the conveying process. The crop circulation, i.e., the time the crop is guided past the chopper blade 10 in the area of the respective crop guide element 15 and thus within the chopper drum, can be reduced. The above geometric parameters allow for ideal crop guidance for a wide variety of crops, cutting lengths, and throughput rates.

[0041] The fourth section 21 of the crop flow element 15 preferably has a radius of curvature Rz between 5 mm and 7 mm, i.e., 6 mm ± 1 mm. This also serves to optimally guide the crop.

[0042] The fifth section 22 of the crop guide element 15 merges into a rectilinear sixth section 23, preferably continuously or tangentially, whereby this sixth section 23 forms an angle δ between 23° and 27°, i.e., 25° ± 2°, with the fastening section 12 of the base body 11. This is also advantageous with regard to optimal crop guidance.

[0043] The material guide element 15 is designed to be closed by sections 24, 25, and 26 adjoining the sixth section 23. Thus, the sixth section 23 of the material guide element 15 transitions into a convexly curved seventh section 24, and the seventh section 24 transitions into a rectilinear eighth section 25, which adjoins the fastening section 12 of the base body 11 and via which the respective material guide element 15 is preferably connected to the fastening section 12 of the base body 11.

[0044] This eighth section 25 merges into a ninth section 26, which contacts the second section 19 of the guide surface 16 of the material guide element 15 with its end facing away from the eighth section 25.

[0045] The ninth section 26 and the second section 19 of the material guide element 15 are preferably connected to one another by welding. This welded connection is preferably formed by laser welding.

[0046] Fig. 4visualizes the advantageous effect of the distance dimension a between the edge 17 of the guide surface 16 of the crop guide element 15 and the transition edge 14 of the base body 11 for guiding the crop using the arrows 27. The first deflection of the chopped crop takes place in the transition area between the cutting section 13 and the fastening section 12 of the base body 11. This is advantageous both with regard to crop guidance and with regard to reducing wear.

[0047] Even with a worn cutting section 13 and longer cutting lengths, the chopped crop does not impact the crop flow element 15. The distance a is selected so that the chopped crop is not conveyed too far into a so-called flight circle of the chopping drum.

[0048] Fig. 5visualizes with an arrow 28 the guidance of the cut crop during the transition into the first section 18 of the guide surface 16 of the crop guide element 15. Due to the relatively flat angle α, a further deflection of the cut crop onto the crop flow element 15 takes place, whereby according to Fig. 6 in the direction of arrow 29, the crop then reaches the second section 19 of the guide surface 16 of the crop guide element 15. The concavely curved section 19 further deflects the chopped crop in the direction of rotation DR of the chopper drum, with the chopped crop guide element 15 accelerating the crop in the direction of rotation DR of the chopper drum.

[0049] In the following, according to Fig. 7In the direction of arrows 30 and 31, the chopped crop initially enters the third section 20 of the guide surface 16 of the crop guide element 15, whereby the reduced radius Ry of the third section 20 further deflects the cut crop in the direction of rotation DR. In the direction of arrow 31, the chopped crop leaves the drum flight circle due to the rotational acceleration caused by the centrifugal force.

[0050] The radius Rz of the fourth section 21 is in the opposite direction and prevents residues of the chopped crop from accumulating in this area.

[0051] The crop guide element 15 prevents the chopped crop from penetrating too far into the drum's flight circle on the inside of the chopping blade 10. This would lead to delayed crop discharge and thus to a longer crop rotation. It can prevent the crop from rotating within the drum housing. Ultimately, the crop transport is designed so that it can be carried out efficiently with low energy consumption.

[0052] The material guide element 15 is designed as a roll profiling element.

[0053] During roll profiling, a blank sheet for the material guide element 15 is formed and surface hardened. This gives the material guide element 15 increased hardness and reduced susceptibility to wear.

[0054] According to an advantageous development, the material guide element 15 has a wear-resistant coating at least on the first section 18, second section 19, and third section 20. Such a wear-resistant coating preferably consists of a tungsten carbide alloy, which can be applied via laser powder deposition welding. This can further reduce the susceptibility of the material guide element 15 to wear.

[0055] The invention further relates to a method for producing the chopping knife 10 described above. During the production of the chopping knife 10, the base body 11 is first provided, which has the fastening section 12 and the cutting section 13 angled relative to the fastening section 12. This can be achieved by bending the cutting section 13 relative to the fastening section 12. Furthermore, at least one material guide element 15 is provided, which is connected to the base body 11. The material guide element 15 is formed by roll profiling a sheet metal blank made of steel and brought into the contour described above from the nine sections 18 to 26. In this case, the first section 18, the second section 19 and the third section 20 of the material guide element 15 are preferably coated with a wear-resistant coating, preferably with a tungsten carbide alloy.The ninth section 26 is preferably welded to the second section 19. List of reference symbols

[0056] 10Chopping knife 11Base body 12Attachment section 13Cutting section 14Transition edge 15Crop guide element 16Guide surface 17Edge 18First section 19Second section 20Third section 21Fourth section 22Fifth section 23Sixth section 24Seventh section 25Eighth section 26Ninth section 27Crop guide 28Crop guide 29Crop guide 30Crop guide 31Crop guide

Claims

1. Chopping blade (10) of a forage harvester, having a basic body (11), which has a fastening portion (12) for fastening the chopping blade (10) to a chopping drum and a cutting portion (13) which is angled in relation to the fastening portion (12) and is intended for harvested crop to be chopped, having at least one crop-guiding element (15) which is fastened to the fastening portion (12) and is intended for guiding chopped harvested crop, wherein a guide surface (16) of said crop-guiding element has a contour which is curved at least in sections and begins at a distance from the one transition edge (14) between the fastening portion (12) and the cutting portion (13), characterized in that a distance (a) between the beginning of the guide surface (16) of the at least one crop-guiding element (15) and the transition edge (14) between the fastening portion (12) and the cutting portion (13) of the basic body (11) is between 4 mm and 8 mm, the guide surface (16) of the at least one crop-guiding element (15) runs rectilinearly adjacent to the beginning of said guide surface in a first portion (18) with a length (b) between 4 mm and 8 mm, wherein the first portion (18) of the at least one crop-guiding element (15) encloses an angle (α) between 18° and 22° with the fastening portion (12) of the basic body (11), the first portion (18) of the at least one crop-guiding element (15) merges into a concavely curved second portion (19), the radius of curvature (Rx) of which is between 21 mm and 25 mm and which has a wrap angle (β) between 29° and 33°, the second portion (19) of the at least one crop-guiding element (15) merges into a concavely curved third portion (20), the radius of curvature (Ry) of which is between 18 mm and 22 mm and which has a wrap angle (γ) between 24° and 28°, the third portion (20) of the at least one crop-guiding element merges into a convexly curved fourth portion (21), a maximum height (c) of the crop-guiding element (15) is between 24 mm and 30 mm starting from the fastening portion (12) of the basic body (11), wherein the at least one crop-guiding element (15) is a roll profiling element.

2. Chopping blade according to Claim 1, characterized in that the fourth portion (21) of the at least one crop-guiding element (15) has a radius of curvature (Rz) between 5 mm and 7 mm, wherein the fourth portion (21) merges into a fifth portion (22) of the guide surface (16), which fifth portion runs parallel to the fastening portion (12) of the basic body (11) and defines the maximum height (c) of the crop-guiding element (15).

3. Chopping blade according to Claim 2, characterized in that the fifth portion (22) of the at least one crop-guiding element (15) merges into a rectilinearly running sixth portion (23) which encloses an angle (δ) between 23° and 27° with the fastening portion (12) of the basic body (11).

4. Chopping blade according to Claim 3, characterized in that the at least one crop-guiding element (15) is closed by portions (24, 25, 26) adjoining the sixth portion (23).

5. Chopping blade according to Claim 3 or 4, characterized in that the sixth portion (23) of the at least one crop-guiding element (15) merges into a convexly curved seventh portion (24) and the seventh portion (24) into a rectilinearly running eighth portion (25) which is adjacent to the fastening portion (12) of the basic body (11).

6. Chopping blade according to Claim 5, characterized in that the eighth portion (25) of the at least one crop-guiding element (15) merges into a ninth portion (26) which makes contact with the second portion (19) of the respective crop-guiding element (15).

7. Chopping blade according to Claim 6, characterized in that the ninth portion (26) is welded to the second portion (19).

8. Chopping blade according to one of Claims 1 to 7, characterized in that the first portion (18), the second portion (19) and the third portion (20) of the at least one crop-guiding element (15) each bear a wear-protection coating.

9. Chopping blade according to Claim 8, characterized in that the wear-protection coating is composed of a tungsten-carbide alloy.

10. Method for producing a chopping blade according to one of Claims 1 to 9, having the following steps: providing the basic body (11), which has the fastening portion (12) and the cutting portion (13) which is angled in relation to the fastening portion (12), providing the at least one crop-guiding element (15), fastening the at least one crop-guiding element (15) to the basic body (11), characterized in that the at least one crop-guiding element (15) is provided by roll profiling of a metal sheet.

11. Method according to Claim 10, characterized in that the at least one crop-guiding element (15) is coated with a wear-protection coating at least on the first portion (18), on the second portion (19) and on the third portion (20).