CN113272502A

CN113272502A - Tooth for attachment to an excavator bucket

Info

Publication number: CN113272502A
Application number: CN201980088622.5A
Authority: CN
Inventors: 巴里斯·厄尔马克; 英戈·内特梅尔; 马克·蒂格斯
Original assignee: ThyssenKrupp AG; ThyssenKrupp Industrial Solutions AG
Current assignee: ThyssenKrupp AG; ThyssenKrupp Industrial Solutions AG
Priority date: 2019-01-11
Filing date: 2019-12-19
Publication date: 2021-08-17
Also published as: WO2020144040A1; EP3908704A1; DE102019200302A1

Abstract

The invention relates to a tooth (20) for attachment to an excavator bucket (12) of a bucket wheel excavator, wherein the tooth (20) is formed in part from a metal matrix composite material, and the metal matrix composite material comprises an insert (44), the insert (44) being cast into a metal based material (42) and being made of a hard material. The invention also relates to a method of manufacturing a tooth (20) for attachment to an excavator bucket (12) of a bucket wheel excavator, comprising: positioning an insert (44) made of a hard material or its reaction partner of tungsten, chromium, niobium and/or vanadium, boron, titanium, silicon and/or tantalum and such as carbon and/or nitrogen in a casting mould for casting a tooth (20), and casting a metal-based material (42) into the tooth (20) such that the insert (44) is at least partially surrounded by the metal-based material (42) of the tooth (20).

Description

Tooth for attachment to an excavator bucket

Technical Field

The present invention relates to a tooth for attachment to an excavator bucket of a bucket wheel excavator, and also to a method for producing such a tooth.

Background

In order to remove hard materials, such as rock in a strip mine, mining machines, such as excavators, and particularly bucket wheel excavators, are used. Such bucket wheel excavators have teeth, in particular digging or cutting teeth, attached to the excavator bucket. Machining of hard materials often causes considerable wear to the teeth, particularly the tooth lips, of the excavator bucket. Such teeth therefore need to be replaced frequently, which results in high downtime and maintenance costs.

DE 202015006273U 1 discloses a tooth for attachment to the excavator bucket of a bucket wheel excavator. The teeth of bucket wheel excavators are typically cast from steel and provided with wear protection. The wear assemblies are typically very fragile and cannot withstand the high loads of the excavation process. The result is rapid wear of the excavator teeth until destroyed.

Disclosure of Invention

Starting from this, it is an object of the present invention to provide a tooth for a bucket wheel excavator, which tooth is easy to manufacture and has high wear resistance.

This object is achieved by a tooth having the features of independent apparatus claim 1 and independent method claim 12. Advantageous developments will become apparent from the dependent claims.

According to a first aspect, a tooth for attachment to an excavator bucket of a bucket wheel excavator is formed from a metal matrix composite, wherein the metal matrix composite comprises an insert cast into a metal based material and made of a hard material. The insert is an anti-wear element. The term "cast into … …" should be understood to mean that the insert is at least partially surrounded by a cast material, in particular a metal-based material.

Hard materials include, for example, ceramics, diamond, carbides, or nitrides. The hard material has in particular a hardness of 950HV30 to 2200HV30, preferably 1500HV30 to 2200HV 30.

Preferably, the metal matrix composite material consists exclusively of one or more inserts and a metal based material. In particular, the entire tooth is formed entirely of the metal matrix composite material. The tooth preferably has a tooth tip and a tooth shank adjacent thereto. The tooth bar is preferably configured in such a way as to be attachable to an excavator bucket. In particular, it is only a tooth tip formed of a metal matrix composite material, wherein the shank is, for example, forged. In particular, the tooth tip is connected to the shank by welding. Forged tooth shanks have better mechanical properties than cast tooth shanks, as a result of which, for example, fractures in the shank region are avoided.

The material to be mined by a bucket wheel excavator is, for example, hard rock such as mineral material, ore, coal, oil sand, limestone, marl, clay, chalky rock, gypsum and similar raw materials.

The insert comprises a hard material, for example from diamond, tungsten carbide, titanium carbide, boron carbide, niobium carbide, chromium carbide, vanadium carbide, silicon carbide, zirconium carbide, tantalum carbide, boron nitride, silicon nitride, titanium nitride and/or ceramics (such as alumina and/or zirconia) or blends of these materials. For example, the insert comprises a hard material, for example from diamond, tungsten carbide, titanium carbide, boron carbide, niobium carbide, chromium carbide, vanadium carbide, silicon carbide, zirconium carbide, tantalum carbide, boron nitride, silicon nitride, titanium nitride or ceramics (such as alumina and/or zirconia) or blends of these materials.

Preferably, the insert comprises about 20% to 80%, preferably 30% to 75%, most preferably 45% to 55% tungsten carbide, wherein the remainder of the insert is primarily carbon as the remainder.

It is also conceivable that the insert comprises about 20% to 80%, preferably 30% to 75%, most preferably 45% to 55% titanium carbide, wherein the remaining component of the insert is mainly carbon as the remaining part. The above description is in volume percent.

The insert has in particular a porous structure, wherein the insert preferably has a plurality of pores, for example, uniformly distributed and/or structured. As an example, the cells are configured in a honeycomb form. The insert is preferably in one piece. The teeth are preferably in one piece and manufactured by a casting process.

Metal matrix composite material is understood to mean a material consisting of a metal-based material, such as steel, into which an insert made of a hard material has been cast. The metal-based material is, for example, a steel having a hardness of about 200-600HB, particularly 350-500HB, preferably 450HB (Brinell hardness), and, for example, has an elongation at break of 1-15%, particularly 2-8%.

Forming the teeth from a metal matrix composite material provides the advantages of simple producibility and high wear resistance resulting from inserts formed from hard materials.

According to a first embodiment, the insert is made of, for example, a hard material or a powdery and/or granular mixture of tungsten, chromium, niobium, vanadium, boron, titanium, silicon, tantalum, or a blend of these elements, by heating. For example, the insert is produced from a pulverulent mixture of tungsten, chromium, niobium, vanadium, boron, titanium, silicon, tantalum or from a blend of these elements by heating. It is likewise conceivable for the insert to be produced from a granular mixture of tungsten, chromium, niobium, vanadium, boron, titanium, silicon, tantalum or from a blend of these elements by heating.

Tungsten, chromium, niobium, vanadium, boron, titanium, silicon or tantalum or mixtures of blends of these elements are preferably mixed with an aggregate/reaction partner, for example with carbon and/or nitrogen, and pressed, bonded or sintered to form an insert, preferably a precursor of an insert. The insert is then placed in a casting mould corresponding to the inverse of the tooth and overmoulded with a metal-based material, in particular hot, so that the insert is surrounded by the metal-based material and the metal-based material at least partially penetrates into the insert, so that the metal-based material enters and fills the pores of the porous insert. The heat acting on the pressed, bonded or sintered material during the casting process ensures that there is a reaction between the various elements and their reaction partners, so that, for example, wear-resistant carbides and nitrides are produced, such as tungsten carbide, titanium carbide, boron carbide, niobium carbide, chromium carbide, vanadium carbide, silicon carbide, tantalum carbide, boron nitride, titanium nitride or silicon nitride and/or blends of these compounds. In this embodiment, the carbide and nitride form an insert within the metal-based material.

It is likewise conceivable for the insert to be produced, for example, from a pulverulent and/or granular mixture of particles (granules), in particular from a hard material comprising a ceramic (such as aluminum oxide and zirconium oxide) or a hard metal (preferably carbides and nitrides, such as tungsten carbide, titanium carbide, boron carbide, niobium carbide, chromium carbide, vanadium carbide, silicon carbide, zirconium carbide, tantalum carbide, boron nitride, silicon carbide and/or titanium nitride or blends of these compounds), wherein the mixture is mixed, for example, with a binder, heated, in particular treated with a gas and baked. The mixture is preferably heated in a flexible mould, for example corresponding to the inverse of the insert. In particular, the insert is made by pressing, gluing or sintering the above-mentioned powdery material and is inserted into a casting mould corresponding to the inverse of the tooth. Preferably, the granulated tungsten carbide, titanium carbide or niobium carbide is mixed with a binder, heated, in particular treated with a gas and baked. In the casting mold, the insert is then surrounded by the metal-based material and at least partially infiltrated.

Subsequently, the mixture is cooled and hardened to form a very wear resistant insert with a porous structure. This offers the possibility of simple production of different forms of insert. The porous structure of the insert should not be understood to mean that the insert must have pores filled with air, but ideally all and realistically most of the pores are filled with a metal-based material.

According to another embodiment, the insert forms at least partially or completely the surface of the tooth. In particular, the inserts on the surface of the teeth are at least partially covered with a metal-based material. The metal-based material is preferably a more ductile, softer material than the material of the insert, which is why the metal-based material wears faster than the insert and is, for example, washed out of holes arranged on the tooth surface.

According to another embodiment, the teeth are partially or completely manufactured by a casting process. Preferably, only the tooth tip is manufactured by a casting process. During the casting process, the insert is positioned in a reverse casting mold having teeth. The metal-based material is then cast into a casting mold such that it infiltrates the pores of the insert and at least partially or completely surrounds the insert with the metal-based material. The casting process represents a particularly simple method of manufacturing the tooth, in which the insert can be placed in a simple manner at any desired point in the casting mould and wear protection can thus be achieved at any desired point of the tooth.

According to another embodiment, the tooth has a plurality of inserts. For example, the plurality of inserts comprise a plurality of particles, in particular hard material particles. Inserts formed from particles, for example prepared by carburizing tungsten with carbon, preferably have a size of 0.2 to 6 microns. Each insert preferably consists of exactly one particle, wherein a plurality of inserts are arranged in a disordered manner in the matrix material. It is also conceivable that the tooth comprises exactly one insert. For example, three inserts preferably extending along the surface of the tooth are arranged within the tooth. Multiple inserts provide the possibility of placing the inserts in the most worn positions. The remaining regions of the teeth may be cast with a more advantageous metal-based material. In particular, the insert has a thickness of about 5mm to 50mm, preferably 5mm to 25 mm. The insert preferably extends over the entire width of the tooth tip.

According to another embodiment, the insert extends at least partially or completely along the surface in the longitudinal direction of the tooth. In particular, the insert extends completely over the entire extent of the tooth tip. Preferably, the tooth comprises only exactly one insert, which constitutes the simplest and most cost-effective embodiment of the tooth.

According to a further embodiment, the tooth has a tooth tip, wherein the insert is arranged in the tooth tip. The tooth tip preferably has a cutting face that ensures improved material removal. The tooth tip is preferably directed in the direction of rotation of the excavator bucket of the bucket wheel excavator and is in contact with the material during the excavation process. Preferably, the tooth has a shank with a fastening region at one end thereof and a tip at an opposite end thereof. The tooth bar preferably has means for securing the tooth to the excavator bucket. In particular, only the tooth tip has an insert, wherein the tooth shank is formed only of the base material. In particular, the tip and shank are in one piece, preferably cast. A two-part construction is also conceivable. Preferably, the insert forms at least partially the surface of the tooth tip and in particular extends along the entire surface of the tooth tip. One or more inserts are preferably arranged in the tooth tip.

According to a further embodiment, the tooth tip has a cutting face which is in contact with the material during the material removal and in particular the cutting of said material. The insert at least partially forms a cutting face. The tooth tip preferably has a plurality of cutting faces, for example three cutting faces. The insert preferably extends completely along the entire cutting face of the tooth tip. In particular, the insert has a V-shaped cross section and is formed, for example, in a shell-shaped manner. Preferably, all outer surfaces of the tooth tip are cutting faces, and the insert is formed, for example, in an envelope-shaped manner such that it extends along the outer surface of the tooth tip. Preferably, the insert is in one piece, and in particular the tooth has exactly one insert. The core of the tooth is preferably formed exclusively from the metal-based material, wherein the insert is arranged exclusively on the region of the surface of the tooth.

According to another embodiment, a plurality of inserts are arranged on each cutting face of the tooth. The inserts are preferably in the form of plates and are arranged in particular adjacent to one another.

According to another embodiment, the tooth tip has a plurality of cutting faces, wherein at least one cutting face is formed predominantly of a metal-based material. By predominantly is meant, for example, from more than 60% to 95%, preferably from 70% to 90%, in particular 80%. In particular, at least one cutting surface or all the remaining cutting surfaces is additionally provided with an insert, in particular extending completely along the cutting surface. As a result, during operation of the tooth, the cutting face of the tooth tip wears to a greater extent than the remaining cutting face provided with the insert, resulting in sharpening of the cutting shape of the tooth, preferably the tooth.

The invention also includes an excavator bucket for attachment to a bucket wheel of a bucket wheel excavator having teeth as described above. Preferably, a plurality of teeth as described above are attached to each excavator bucket. In particular, the or each tooth of the excavator bucket comprises an insert embedded in the base material.

The invention also includes a method of manufacturing a tooth for attachment to an excavator bucket of a bucket wheel excavator, the method comprising the steps of:

positioning an insert made of a hard material or a reaction partner of tungsten, chromium, niobium and/or vanadium, boron, titanium, silicon and/or tantalum and preferably such as carbon and/or nitrogen in a casting mould for casting a tooth, and

casting a metal-based material into the teeth such that the inserts are at least partially surrounded by the metal-based material of the teeth.

The advantages and explanations described with reference to the tooth apply correspondingly in terms of method to the method for producing the tooth.

According to one embodiment, the insert is manufactured by binding, pressing or sintering a powdery and/or granular mixture of hard materials prior to the positioning operation.

According to one embodiment, the tooth has a tooth tip and a tooth shank, wherein the tooth tip is produced by casting and the tooth shank is forged, wherein the tooth tip is subsequently connected, preferably welded, to the tooth shank.

According to another embodiment, a mixture of tungsten, chromium, niobium, vanadium, boron, titanium, silicon and/or tantalum and/or a blend of these elements is pressed into the insert before positioning the insert.

According to another embodiment, during the casting process, the material of the insert reacts to form carbides.

Drawings

The invention will be explained in more detail below on the basis of a number of exemplary embodiments with reference to the drawings.

FIG. 1 shows a schematic diagram of a front view of a bucket wheel excavator having a plurality of excavator buckets according to one exemplary embodiment.

Fig. 2 shows a schematic illustration of an isometric view of a tooth of an excavator bucket for attachment to a bucket wheel excavator, according to an example embodiment.

Fig. 3 shows a schematic illustration of an isometric cross-sectional view of a tooth of an excavator bucket for attachment to a bucket wheel excavator according to the exemplary embodiment of fig. 2.

Detailed Description

Fig. 1 shows a bucket wheel 10 of a bucket-wheel excavator for crushing bulk material or of a bridge bucket-wheel reclaimer for reclaiming bulk material, for example, in particular in an open-pit mine or a storage yard. Preferably, such wheels are used for mining or recovering minerals, ores, sand, clay, gravel, oil sands, coal or other particulate materials. The bucket wheel 10 of fig. 1 has a bucket wheel frame 18 of a generally annular form, the bucket wheel frame 18 having a plurality of segments, for example, in the shape of partial circular rings. A plurality of excavator buckets 2 are mounted on the bucket wheel frame 18. As an example, the bucket wheel 10 shown in fig. 1 has eight buckets 12, and the eight buckets 12 are attached to the outer periphery of the bucket wheel frame 18 in a manner evenly spaced from each other. Each bucket 12 is attached to the bucket wheel frame 18 so as to be rotatable about a pivot axis.

During operation, the bucket wheel 10 rotates about the central axis of the bucket wheel frame. In the example of fig. 1, the direction of rotation is indicated, for example, as counterclockwise. Preferably, each excavator bucket 12 has two opposing

cutting edges

14, 16 so that the bucket wheel 10 can be operated in both rotational directions so that the cutting edges 14, 16 of the bucket 12 pointing in the direction of rotation of the bucket wheel can engage the material to be removed. As described with reference to fig. 2-5, a plurality of teeth 20 are attached to each of the excavator buckets 12, respectively. The teeth are preferably attached to

respective cutting edges

12, 14 of an excavator bucket 12.

Fig. 2 shows a tooth 20 for attachment to an excavator bucket (not shown). The tooth 20 comprises a tooth tip 22 and a tooth shank 24, wherein the tooth tip 22 is constructed, for example, as a single piece with the tooth shank 24. It is likewise conceivable for the tooth shank 24 and the tooth tip 22 to be constructed as separate components and subsequently to be connected to one another (e.g. welded). Preferably, the shank 24 directly abuts the tooth tip 22 and is particularly useful for securing the tooth 20 to the excavator bucket 12 of a bucket wheel excavator. The tooth tip 22 forms the front end of the tooth 20, which is directed in the direction of rotation of the bucket wheel 10 during operation of the tooth 20. The tooth tip 22 is tooth-shaped and configured to narrow in the direction of the tip of the tooth 10. The tooth tip 22 has a triangular or rectangular cross-sectional area, for example. Preferably, the tooth point 22 has four outer surfaces, namely two respectively opposed lateral cutting faces 26, an upper face 28 and a lower cutting face 30.

The tooth shank 24 has, for example, two

wings

30, 32 extending parallel to one another. Each

tab

32, 34 has a

hole

36, 38 which is in particular opposite the corresponding

hole

36, 38 of the

other tab

32, 34 in a flush manner. The

holes

36, 38 are for receiving a fastening device (not shown) for fastening the tooth 22 to the excavator bucket 12. Preferably, the tooth 20 has a stop 40 on an end region of the tooth shank 24, the stop 40 being used to position the tooth 20 on the excavator bucket 12, and with the tooth 20 mounted on the excavator bucket 12, the stop 40 abuts against said excavator bucket, in particular against the cutting edges 14, 16 of the excavator bucket 12. Preferably, the handles are fastened to the cutting edges 14, 16 of the excavator bucket 12.

The tooth 20 is formed of a metal matrix composite material including an insert 44, the insert 44 being cast into the metal base material 42 and being made of a hard material. The insert is preferably formed of a hard material and has a porous structure. Hard materials include, for example, tungsten carbide, ceramics (such as alumina and zirconia), titanium carbide, boron carbide, niobium carbide or chromium carbide or blends of these materials. The metal-based material 28 comprises a more ductile material than the insert 44 (such as steel) and is cast into the insert 44. The metal-based material 42 in particular penetrates into the insert 44, wherein a material-bonded fixed connection is formed between the insert 44 made of a hard material and the metal-based material 28.

The tooth 20 is preferably manufactured by a casting process and is in particular in one piece. For example, the at least one insert 44 is produced from a powdery and/or granular mixture comprising particles (granules) of tungsten carbide, ceramics (such as aluminum oxide and zirconium oxide), titanium carbide, boron carbide, niobium carbide or chromium carbide, or from a blend of these materials, wherein the mixture is mixed, for example, with a binder, heated, in particular treated with a gas and baked. In particular, the mixture is heated in a flexible mould, for example of the inverse type corresponding to the insert 44. Subsequently, the mixture cools and hardens, forming a very wear resistant body with a porous structure. To manufacture the tooth 20, the insert 44 is placed in a casting mold corresponding to the inverse of the tooth 20. Subsequently, a metal-based material is cast into the casting mold such that it penetrates into the insert 44 and at least partially or completely surrounds it.

In the exemplary embodiment of fig. 1, the insert 44 is configured such that it extends over the entire cutting face of the tooth 20. Preferably, the insert 44 at least partially forms the lateral cutting face 26 and the lower cutting face 30 and is of one-piece form. It is also conceivable for the insert to be formed by a plurality of segments arranged next to one another. The insert 44 is cast into the metal matrix material 28 such that the metal matrix material preferably infiltrates the insert. By way of example, the entire tooth 20 is formed from a metal matrix composite material. The upper face 28 of the tooth point 22 is, for example, free of the insert 44, wherein only the upper end of the insert 44 of the cutting face 26 forms part of the upper face 28 of the tooth point 22. The upper face 28 is formed mostly or entirely of a metal-based material. Thus, during operation of the tooth 20, the upper face wears more quickly than the insert 44, causing the tooth form of the tooth 20 to become sharp.

Fig. 3 shows a sectional view of the tooth 20 according to fig. 2, wherein like elements are denoted by like reference numerals. The insert 44 extends over the entire area of the cutting face 26 and the lower cutting face 30 and is preferably shell-shaped and in one piece.

List of reference numerals

10 bucket wheel

12 excavator bucket

14 cutting edge

16 cutting edge

18 bucket wheel frame

20 teeth

22 tooth point

24-tooth handle

26 cutting surface

28 upper side

30 lower cutting surface

32 wing

34 wing

36 holes

38 holes

40 stop part

42 metal-based material

44 an insert.

Claims

1. A tooth (20) for attachment to an excavator bucket (12) of a bucket wheel excavator,

it is characterized in that the preparation method is characterized in that,

the tooth (20) is formed of a metal matrix composite material and includes an insert (44), the insert (44) being cast into a metal-based material (42) and being made of a hard material.

2. The tooth (20) of claim 1, wherein the insert (44) is fabricated from a hard material or a powdered and/or granular mixture of tungsten, chromium, niobium, vanadium, boron, titanium, silicon, and/or tantalum by heating.

3. The tooth (20) of any of the preceding claims, wherein the insert (44) at least partially forms a surface of the tooth (20).

4. The tooth (20) according to any of the preceding claims, wherein the tooth (20) is manufactured by a casting process.

5. The tooth (20) according to any of the preceding claims, wherein the tooth (20) comprises a plurality of inserts (44).

6. The tooth (20) of any of the preceding claims, wherein the insert (44) extends at least partially in a longitudinal direction along a surface of the tooth (20).

7. The tooth (20) of any of the preceding claims, wherein the tooth (20) comprises a tooth tip (22) and the insert (44) is disposed in the tooth tip (22).

8. The tooth (20) of claim 7, wherein the tip (22) has at least one cutting face (26, 28, 30) and the insert at least partially forms the cutting face (26, 28, 30).

9. The tooth (20) of claim 7 or 8, wherein a plurality of inserts (44) are disposed on each cutting face (26, 28, 30) of the tooth (20).

10. The tooth (20) of claim 7, wherein the tip (22) has a plurality of cutting faces (26, 28, 30), and a majority of at least one cutting face (26, 28, 30) is formed from the metal-based material (42).

11. An excavator bucket (12) for attachment to a wheel frame (18) of a bucket wheel excavator, comprising a tooth (20) according to any one of the preceding claims.

12. A method of manufacturing a tooth (20) for attachment to an excavator bucket (12) of a bucket wheel excavator, comprising:

casting the teeth (20) by positioning an insert (44) made of a hard material or tungsten, chromium, niobium and/or vanadium, boron, titanium, silicon and/or tantalum in a casting mould, and

casting a metal-based material (42) into the teeth (20) such that the insert (44) is at least partially surrounded by the metal-based material (42) of the teeth (20).

13. Method according to claim 12, wherein, before said positioning operation, said insert (44) is made by heating a powdery and/or granular mixture of hard materials.

14. The method according to any one of claims 12 or 13, wherein the tooth (20) has a tip (22) and a shank (24), and wherein the tip (22) is manufactured by casting and the shank (24) is forged, wherein the tip is subsequently connected to the shank (24).

15. The method according to any one of claims 12 to 14, wherein a mixture of tungsten, chromium, niobium, vanadium, boron, titanium, silicon and/or tantalum and/or a blend of these elements is pressed into the insert before positioning the insert.

16. The method of claim 15, wherein during the casting process, the material of the insert reacts to form carbides.