DE102019200302A1 - Tooth for attachment to an excavator bucket - Google Patents

Abstract

The present invention relates to a tooth (20) for attachment to an excavator bucket (12) of a bucket wheel excavator, the tooth (20) being formed from a metal matrix composite and the metal matrix composite being an insert (44) cast into a metal matrix material (42). The invention also relates to a method for producing 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 tungsten, chromium, niobium and / or vanadium , Boron, titanium silicon and / or tantalum and their reactants such as carbon and / or nitrogen in a mold for casting the tooth (20) and - casting the tooth (20) from a metal matrix material (42), so that the insert (44) is at least partially enclosed by the metal matrix material (42) of the tooth (20).

Description

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

Digging machines such as excavators, in particular bucket wheel excavators, are used to solve hard materials, such as rock in an open-cast mine. Such bucket wheel excavators have teeth, in particular digging or cutting teeth, which are attached to the excavator bucket. Machining hard materials often causes significant wear to the teeth of the excavator bucket, especially the tooth tips. There is therefore a need to replace such teeth frequently, which leads to high downtimes and maintenance costs.

From the DE 20 2015 006 273 U1 a tooth for attachment to an excavator bucket of a bucket wheel excavator is known. The teeth of a bucket wheel excavator are usually cast from a steel and provided with wear protection. This wear protection is often very brittle and does not withstand the high loads of an excavator process. The result is rapid wear and tear and even destruction of the excavator tooth.

Based on this, it is an object of the present invention to provide a tooth for a bucket wheel excavator that is simple to manufacture and has a high wear resistance.

This object is achieved by a tooth with the features of independent device claim 1 and independent method claim 12. Advantageous further developments result 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 material, the metal matrix composite material having an insert made of a hard material cast into a metal matrix material. The insert is a wear protection element. The term “cast in” is to be understood to mean that the insert is at least partially enclosed with the cast material, namely the metal matrix material.

Hard materials include, for example, ceramics, diamonds, carbides or nitrides. Hard materials in particular have a hardness of 950HV30 to 2200 HV30, preferably 1500HV30 to 2200HV30.

The metal matrix composite material preferably consists exclusively of one or more inlays and a metal matrix material. In particular, the entire tooth is made entirely of the metal matrix composite material. The tooth preferably has a tooth head and an adjoining tooth shaft. The toothed shaft is preferably designed such that it can be connected to an excavator shovel. In particular, only the tooth tip is formed from the metal matrix composite material, the tooth shaft being forged, for example. In particular, the tooth head is connected to the tooth shaft by means of welding. A forged tooth shaft has better mechanical properties than a cast tooth shaft, which prevents breakages in the shaft area, for example.

The material to be mined with the bucket wheel excavator is, for example, hard rock, such as mineral material, ores, coal, oil sand, limestone, marl, clay, chalk, plaster and similar raw materials.

The insert comprises, for example, a hard material from the list 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 ceramic, such as aluminum and / or zirconium oxide, or one Mixture of these materials. For example, the insert comprises a hard material from the list 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 ceramic, such as aluminum and / or zirconium oxide, or a mixture of these materials.

The insert preferably comprises about 20% to 80%, preferably 30% to 75%, most preferably 45% -55% tungsten carbide, the remaining component of the insert being mainly carbon with a remainder.

It is also conceivable that the insert comprises approximately 20% to 80%, preferably 30% to 75%, most preferably 45% to 55% titanium carbide, the remaining component of the insert being mainly carbon with a remainder. The preceding information is volume percent.

The insert has, in particular, a porous structure, the insert preferably having a plurality of pores which are, for example, evenly distributed and / or formed. For example, the pores are honeycomb-shaped. The insert is preferably formed in one piece. The tooth is preferably formed in one piece and produced by a casting process.

A metal matrix composite material is to be understood as a material made of a metal matrix material, such as steel, into which the insert is cast from a hard material. The metal matrix material is, for example, a steel with a hardness of approximately 200-600 HB, in particular 350-500 HB, preferably 450 HB (Brinell) and, for example, an elongation at break of greater than or equal to 1-15%, in particular 2-8% .

The formation of the tooth from a metal matrix composite material offers the advantage of simple manufacture and high wear protection, which results from the insert formed from a hard material.

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

The mixture of tungsten, chromium, niobium vanadium, boron, titanium, silicon or tantalum or a mixture of these elements is preferably mixed with an additive / reactant such as, for example, with carbon and / or nitrogen and to the insert, preferably a precursor of the insert pressed, glued or sintered. The insert is then placed in a casting mold that corresponds to the negative shape of the tooth and poured with the hot metal matrix material, so that the insert is enclosed by the metal matrix material and the metal matrix material at least partially infiltrates into the insert, so that the metal matrix material penetrates into the pores of the porous ones Insert and fills it out. The heat acting on the pressed, glued or sintered materials in the casting process ensures a reaction between the various elements and their reaction partners, so that, for example, wear-resistant carbides and nitrides, such as tungsten carbide, titanium carbide, boron carbide, niobium carbide, chromium carbide, vanadium carbide, silicon carbide, tantalum carbide, Boron nitride, titanium nitride, silicon nitride and / or a mixture of these arise. In this embodiment, the carbides and nitrides form the insert within the metal matrix material.

It is also conceivable for the insert to consist, for example, of a powdery and / or granular mixture of particles (grains), in particular hard materials comprising ceramic, such as aluminum and zirconium oxide or 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 nitride and / or titanium nitride, or a mixture of these compounds is produced, the mixture being mixed, for example, with a binder, heated, in particular gassed, and baked. The mixture is preferably heated in a flexible form, for example, which corresponds to the negative form of the insert. In particular, the insert is produced by pressing, gluing or sintering the aforementioned powdery material and inserted into the casting mold, which corresponds to the negative shape of the tooth. Granular tungsten carbide, titanium carbide or niobium carbide is preferably mixed with a binder, heated, in particular gassed, and baked. The insert is then enclosed in the casting mold by the metal matrix material and at least partially inflated.

The mixture then cools down and hardens to a very wear-resistant insert with a porous structure. This offers a possibility of easily producing different forms of the insert. A porous structure of the insert is not to be understood to mean that it inevitably has pores filled with air, rather the pores are ideally all, realistically for the most part, filled with the metal matrix.

According to a further embodiment, the insert forms the surface of the tooth at least partially or completely. In particular, the insert on the surface of the tooth is at least partially covered with the metal matrix material. The metal matrix material is preferably a ductile, softer material than the material of the insert, which is why the metal matrix material wears out faster than the insert and is washed out, for example, from the pores arranged on the surface of the tooth.

According to a further embodiment, the tooth is partially or completely produced by a casting process. Preferably, only the tooth head is made by a casting process. In the casting process, the insert is positioned in a mold that has the negative shape of the tooth. The metal matrix material is then poured into the casting mold so that it infiltrates into the pores of the insert and at least partially or completely encloses the insert with the metal matrix material. The casting process represents a particularly simple way of producing the tooth, the insert being placed in a simple manner at any point within the casting mold can be achieved and thus wear protection can be achieved at any point on the tooth.

According to a further embodiment, the tooth has a plurality of deposits. For example, the plurality of deposits comprises a plurality of particles, in particular hard material particles. An insert formed from a particle preferably has a size of 0.2 microns to 6 microns, the particles being produced, for example, by carburizing tungsten with carbon. Each insert preferably consists of exactly one particle, the deposits being arranged in a disordered manner in the matrix material. It is also conceivable that the tooth has exactly one insert. For example, three inlays are arranged within the tooth, which preferably extend along the surface of the tooth. A large number of inserts offers the possibility of arranging them where the wear is greatest. The remaining areas of the tooth can be cast with the cheaper metal matrix material. In particular, the insert has a thickness of approximately 5 mm to 50 mm, preferably 5 mm to 25 mm. The insert preferably extends over the entire width of the tooth head.

According to a further embodiment, the insert extends at least partially or completely in the longitudinal direction of the tooth along the surface. In particular, the insert extends completely over the entire extent of the tooth head. The tooth preferably has only one insert, which is the simplest and most cost-effective embodiment of the tooth.

According to a further embodiment, the tooth has a tooth head, the insert being arranged in the tooth head. The tooth head preferably has a cutting surface which ensures improved removal of the material. The tooth head preferably points in the direction of rotation of the excavator bucket of the bucket wheel excavator and comes into contact with the material during the excavation process. The tooth preferably has a tooth shaft with a fastening region at one end and the tooth head at its opposite end. The toothed shaft preferably has means for attaching the tooth to an excavator bucket. In particular, only the tooth head has an insert, the tooth shaft being formed exclusively from the matrix material. In particular, the tooth head and the tooth shaft are formed in one piece, preferably cast. A two-part training is also conceivable. The insert preferably forms at least partially the surface of the tooth head and extends in particular along the entire surface of the tooth head. One or more deposits are preferably arranged in the tooth head.

According to a further embodiment, the tooth head has a cutting surface which comes into contact with the material when the material is removed and in particular cuts it. The insert at least partially forms the cutting surface. The tooth head preferably has a multiplicity of cutting surfaces, for example three cutting surfaces. The insert preferably extends completely along the entire cutting surface of the tooth head. In particular, the insert has a V-shaped cross section and is, for example, of a bowl-shaped design. Preferably, all of the outer surfaces of the tooth head are cutting surfaces and the insert is, for example, designed in the form of a shell so that it extends along the outer surfaces of the tooth head. The insert is preferably formed in one piece and the tooth in particular has exactly one insert. The core of the tooth is preferably formed exclusively from the metal matrix material, the insert being arranged only on the regions of the surface of the tooth.

According to a further embodiment, a plurality of inlays are arranged on each cutting surface of the tooth. The inserts are preferably plate-shaped and in particular are arranged next to one another.

According to a further embodiment, the tooth head has a plurality of cutting surfaces, at least one cutting surface being largely made of the metal matrix material. A large part is, for example, more than 60% to 95%, preferably 70% to 90%, in particular 80%. In particular, at least one cutting surface or all other cutting surfaces are additionally provided with an insert which in particular extends completely along the cutting surfaces. As a result, a cutting surface of the tooth head will wear out more during operation of the tooth than the other cutting surfaces equipped with the insert, thereby sharpening the tooth, preferably the cutting shape of the tooth.

The invention also includes an excavator bucket for attachment to a bucket wheel of a bucket wheel excavator with a tooth as described above. Preferably, a plurality of teeth described above are attached to each bucket. In particular, at least one tooth or each tooth of an excavator bucket has an insert embedded in matrix material.

• - Positionieren einer Einlage aus einem Hartstoff oder Wolfram, Chrom, Niob und/oder Vanadium, Bor, Titan Silizium und/oder Tantal und vorzugsweise einem Reaktionspartner wie beispielsweise Kohlenstoff und/oder Stickstoff in einer Gussform zum Gießen des Zahns und
• - Gießen des Zahns aus einem Metallmatrixmaterial, sodass die Einlage zumindest teilweise von dem Metallmatrixmaterial des Zahns umschlossen wird.

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

• - Positioning an insert made of a hard material or tungsten, chromium, niobium and / or vanadium, boron, titanium silicon and / or tantalum and preferably a reactant such as carbon and / or nitrogen in a mold for casting the tooth and
• Casting the tooth from a metal matrix material so that the insert is at least partially enclosed by the metal matrix material of the tooth.

The advantages and explanations described with regard to the tooth also apply to the method for producing the tooth in a procedural correspondence.

According to one embodiment, the insert is produced from a powdery and / or granular mixture of a hard material by means of gluing, pressing, sintering before positioning.

According to one embodiment, the tooth has a tooth head and a tooth shaft, the tooth head being produced by casting and the tooth shaft being forged, the tooth head subsequently being connected, preferably welded, to the tooth shaft.

Figure list

• 1 zeigt eine schematische Darstellung eines Schaufelrades eines Schaufelradbaggers mit einer Mehrzahl von Baggerschaufeln in einer Frontansicht gemäß einem Ausführungsbeispiel.
• 2 zeigt eine schematische Darstellung eines Zahns zum Anbringen an eine Baggerschaufel eines Schaufelradbaggers in einer isometrischen Ansicht gemäß einem Ausführungsbeispiel.
• 3 zeigt eine schematische Darstellung eines Zahns zum Anbringen an eine Baggerschaufel eines Schaufelradbaggers in einer isometrischen Schnittansicht gemäß dem Ausführungsbeispiel der 2.

The invention is explained in more detail below using several exemplary embodiments with reference to the accompanying figures.

• 1 shows a schematic representation of a bucket wheel of a bucket wheel excavator with a plurality of excavator buckets in a front view according to an embodiment.
• 2nd shows a schematic representation of a tooth for attachment to an excavator bucket of a bucket wheel excavator in an isometric view according to an embodiment.
• 3rd shows a schematic representation of a tooth for attachment to an excavator bucket of a bucket wheel excavator in an isometric sectional view according to the embodiment of FIG 2nd .

1 shows a paddle wheel 10th for example, a bucket wheel excavator for mining bulk goods or a bridge bucket wheel device for reloading bulk goods, especially in an open pit or storage area. Such paddle wheels are preferably used for mining or reloading minerals, ores, sand, clay, gravel, oil sand, coal or other granular materials. The paddle wheel 10th of the 1 has a paddle wheel frame 18th which is essentially ring-shaped and has, for example, a plurality of segments in the form of part circular rings. On the paddle wheel frame 18th are a plurality of excavator buckets 12th appropriate. This is exemplified in 1 shown paddle wheel 10th eight scoops 12th on, which are evenly spaced from each other on the outer periphery of the impeller frame 18th are attached. Every scoop 12th is rotatable about a swivel axis on the paddle wheel frame 18th appropriate.

The paddle wheel 10th rotates around the central axis of the bucket wheel frame during operation. In the example of 1 the direction of rotation is given, for example, counterclockwise. Each excavator bucket preferably has 12th two opposite cutting edges 14 , 16 on so that the operation of the paddle wheel 10th is possible in both directions of rotation, so that the cutting edge pointing in the direction of rotation of the impeller 14 , 16 the shovel 12th can intervene in the material to be removed. On each of the excavator buckets 12th are a plurality of teeth each 20 attached as with respect to the 2nd to 5 described. The teeth are preferably on the respective cutting edge 12th , 14 the excavator shovel 12th appropriate.

2nd shows a tooth 20 for attachment to an excavator bucket, not shown. The tooth 20 includes a tooth head 22 and a tooth shaft 24th , with the tooth head 22 with the tooth shaft 24th is designed in one piece as an example. It is also conceivable to use the tooth shaft 24th and the tooth head 22 Form as separate components and then connect them together, for example to weld. The tooth shaft preferably closes 24th directly to the tooth head 22 and serves in particular to secure the tooth 20 on an excavator shovel 12th a bucket wheel excavator. The tooth head 22 forms the front end of the tooth 20 from that in the operation of the tooth 20 in the direction of rotation of the paddle wheel 10th points. The tooth head 22 is tooth-shaped and towards the tip of the tooth 10th tapered. The tooth head 22 has, for example, a triangular or quadrangular cross-sectional area. The tooth head preferably has 22 four outer surfaces, namely two opposite, lateral cutting surfaces 26 , an upper surface 28 and a lower cutting surface 30th .

The tooth shaft 24th has two legs as an example 30th , 32 that extend parallel to each other. Each of the thighs 32 , 34 has holes 36 , 38 , the respective holes 36 , 38 of the other leg 32 , 34 in particular face to face. The holes 36 , 38 are used to hold fasteners, not shown, for fastening the tooth 22 on an excavator shovel 12th . The tooth preferably has 20 at the end of the tooth shaft 24th a stop 40 on, the one for positioning the tooth 20 on the excavator bucket 12th serves and one on an excavator bucket 12th assembled tooth 20 at this, especially the cut edge 14 , 16 the excavator shovel 12th is present. The tooth shaft is preferably at the cutting edge 14 , 16 the excavator shovel 12th attached.

The tooth 20 is formed from a metal matrix composite, the metal matrix composite being a metal matrix material 42 cast insert 44 has a hard material. The insert is preferably made of a hard material and has a porous structure. The hard material includes, for example, tungsten carbide, ceramic, such as, for example, aluminum and zirconium oxide, titanium carbide, boron carbide, niobium carbide or chromium carbide, or a mixture of these materials. The metal matrix material 28 comprises a more ductile material than the insert 44 , such as steel and is in the insert 44 poured. The metal matrix material 42 is particularly in the deposit 44 infiltrated, whereby a cohesive, firm connection between the deposits 44 made of a hard material and the metal matrix material 28 will be produced.

The tooth 20 is preferably produced by a casting process and in particular is formed in one piece. For example, the at least one insert 44 made from a powdery and / or granular mixture of particles (grains) comprising tungsten carbide, ceramic, such as aluminum and zirconium oxide, titanium carbide, boron carbide, niobium carbide or chromium carbide, or from a mixture of these materials, the mixture being mixed, for example, with a binder, heated, in particular fumigated, and baked. In particular, the mixture is heated in a flexible form, for example, that of the negative form of the insert 44 corresponds. The mixture then cools down and hardens to a very wear-resistant body with a porous structure. The deposit 44 is used to make the tooth 20 placed in a mold that matches the negative shape of the tooth 20 corresponds. The metal matrix material is then poured into the mold so that it is inserted into the insert 44 filtered and at least partially or completely encloses it.

The deposit 44 is in the embodiment of 1 formed such that they cover the entire cutting surface of the tooth 20 extends. The insert preferably forms 44 at least partially the side cutting surfaces 26 and the lower cutting surface 30th and is formed in one piece. It is also conceivable for the insert to be formed from a plurality of segments which are arranged next to one another. The deposit 44 is in the metal matrix material 28 poured so that this preferably infiltrates into the insert. The entire tooth is exemplary 20 formed from the metal matrix composite. The top surface 28 of the tooth head 22 has no deposit as an example 44 with only the top ends of the inlays 44 the cutting surfaces 26 part of the top surface 28 of the tooth head 22 form. The top surface 28 is largely or completely formed from the metal matrix material. In the operation of the tooth 20 therefore it wears out faster than the insert 44 so that the tooth shape of the tooth 20 tightened.

3rd shows the tooth 20 according to 2nd in a sectional view, wherein the same elements are identified with the same reference numerals. The deposit 44 extends over the entire area of the cutting surfaces 26 and the lower cutting surface 30th and is preferably cup-shaped and in one piece.

Reference list

10th

Paddle wheel

12th

Excavator bucket

14

Cutting edge

16

Cutting edge

18th

Paddle wheel frame

20

tooth

22

Tooth head

24th

Tooth shaft

26

Cutting surface

28

top surface

30th

lower cutting surface

32

leg

34

leg

36

drilling

38

drilling

40

attack

42

Metal matrix material

44

inlay

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 202015006273 U1 [0003]

Claims (14)

Tooth (20) for attachment to an excavator bucket (12) of a bucket wheel excavator, characterized in that the tooth (20) is formed from a metal matrix composite material and the metal matrix composite material is an insert (44) cast from a hard material into a metal matrix material (42) having. Tooth (20) after Claim 1 , wherein the insert (44) is made from a powdery and / or granular mixture of a hard material or tungsten, chromium, niobium, vanadium, boron, titanium silicon and / or tantalum by heating. Tooth (20) according to one of the preceding claims, wherein the insert (44) at least partially forms the surface of the tooth (20). Tooth (20) according to one of the preceding claims, wherein the tooth (20) is produced by a casting process. Tooth (20) according to any one of the preceding claims, wherein the tooth (20) has a plurality of deposits (44). Tooth (20) according to any one of the preceding claims, wherein the insert (44) extends at least partially in the longitudinal direction along the surface of the tooth (20). Tooth (20) according to one of the preceding claims, wherein the tooth (20) comprises a tooth head (22) and the insert (44) is arranged in the tooth head (22). Tooth (20) after Claim 7 , wherein the tooth head (22) has at least one cutting surface (26, 28, 30) and the insert at least partially forms the cutting surface (26, 28, 30). Tooth (20) after Claim 7 or 8th wherein a plurality of inserts (44) are arranged on each cutting surface (26, 28, 30) of the tooth (20). Tooth (20) after Claim 7 , wherein the tooth head (22) has a plurality of cutting surfaces (26, 28, 30) and at least one cutting surface (26, 28, 30) is largely made of the metal matrix material (42). Excavator bucket (12) for attachment to a bucket wheel frame (18) of a bucket wheel excavator comprising a tooth (20) according to one of the preceding claims. DB = EPODOC & ... PN = EP0867611 A method for producing 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 tungsten, chromium, niobium and / or vanadium, boron, titanium silicon and / or tantalum in a mold for casting the tooth (20) and - Casting the tooth (20) from a metal matrix material (42) so that the insert (44) is at least partially enclosed by the metal matrix material (42) of the tooth (20). Procedure according to Claim 12 , wherein the insert (44) is made by heating from a powdery and / or granular mixture of a hard material prior to positioning. Procedure according to one of the Claims 12 or 13 , wherein the tooth (20) has a tooth head (22) and a tooth shaft (24) and wherein the tooth head (22) is produced by casting and the tooth shaft (24) is forged, the tooth head subsequently being connected to the tooth shaft (24) becomes.

Images