EP1754855B1 - Tool, in particular for a tunnel boring machine - Google Patents

Description

The invention relates to a roller bit, in particular for tunnel boring machines, with carrier body and with a connected to the support body and rotating over the circumference of the support body cutting ring, the cutting ring consists of a plurality of over the circumference of the cutting ring successively arranged cutting ring segments. Such roller bits are also referred to as a disc chisel.

Roller bits are the main cutting tools of a cutting wheel of a tunnel boring machine (TBM). The roller bits generally have a cylindrical carrier body and over the circumference of this carrier body of the cutting ring runs around. The cutting ring is usually made of a hard material and in practice, in particular cutting rings made of alloyed steels with high carbon content, but also cutting rings with carbide inserts. Known from practice cutting rings are subject to an undesirably high wear, so that the relevant roller bits must be replaced after relatively short periods of time. Such an exchange of tools is very expensive and it must be taken in particular disadvantageous tunneling interruptions in the tunneling of the tunnel boring machine in purchasing.

A roller chisel of the type described above is out US 3,981,370 A. known. In this roller chisel distributed cutting ring segments are provided over the circumference of a support body, which are keyed to the support body. - Out DE 26 30 932 A is a wear-resistant composite known. This composite material consists of hard materials and a metal matrix and carbides are mentioned among other things as hard materials.

The invention is based on the technical problem of specifying a roller bit of the type mentioned, the cutting ring has a high resistance and a relatively low wear and thus achieved a long service life.

To solve this technical problem, the invention teaches a roller bit, in particular for tunnel boring machines, comprising a carrier body and a cutting ring connected to the carrier body and circulating around the circumference of the carrier body, the cutting ring consisting of a steel matrix and hard metal particles distributed therein, the grain size of the hard metal particles 1 mm to 10 mm, wherein the hard metal particles to at least 70 vol .-% of tungsten carbide and at least one binder, said cutting ring consists of a plurality of over the circumference of the cutting ring successively arranged cutting ring segments and wherein the cutting ring segments are welded to the carrier body ,

Preferably, the hard metal particles consist of at least 70% by volume of tungsten carbide and the remainder consists exclusively of at least one binder. Thus, for example, if the cemented carbide particles comprise 90% tungsten carbide by volume, they consist of 10% by volume binder. By the term hard metal particles are meant in the context of the invention, moreover, defined particles which consist of a different material than the steel matrix of the cutting element.

The cutting ring surrounds the carrier body annular or with a circular cross-section. According to the invention, the cutting ring consists of a plurality of cutting ring segments arranged one behind the other along the cutting ring or over the circumference of the carrier body. It is expediently to curved cutting ring segments, which are located on the support body Add to the cutting ring. Preferably, a gap or gap is provided between two cutting ring segments. By realizing such gaps between the cutting ring segments, in particular fluctuations caused by temperature fluctuation can be avoided. The length of a cutting ring segment preferably corresponds to 1/5 to 1/15, preferably 1/8 to 1/12 of the circumference of the cutting ring. According to a preferred embodiment, the length of a cutting ring segment corresponds to 1/10 or approximately 1/10 of the circumference of the cutting ring. It should also be noted that in particular roller bits are used with roller bit diameters of 10 to 20 inches, having the aforementioned cutting ring segments.

According to the invention, the cutting ring is welded onto the carrier body or the cutting ring segments are welded onto the carrier body. The support body is expediently made of steel or of a steel alloy, which does not differ significantly from the common steel alloys that are currently used. The steel matrix of the cutting ring or the cutting ring segments is welded to the carrier body. The welding of the cutting ring and the cutting ring segments with the carrier body is essential and advantageous in the context of the invention. As a result, a very strong composite of the cutting ring according to the invention or, the cutting ring segments according to the invention with the carrier body is achieved. According to a very preferred embodiment of the invention, a cutting ring segment aufzuschweißendes carrier body side two in cross-section (transverse to the longitudinal direction of the cutting ring segment) obliquely to the center of the cutting ring segment and the carrier body toward each other on welding surfaces. A cutting ring segment expediently has a triangular or approximately triangular tulip-shaped carrier body-side section or welding section. The triangle tip is arranged carrier body side. Preferably then has the the aufzuschweißenden Cutting ring segment associated carrier body section cutting ring segment side also two in cross-section obliquely to the center of the carrier body and the cutting ring segment towards each other on welding surfaces. Expediently, this carrier body section has a cross-sectionally triangular or approximately triangular or tulip-shaped cutting-ring segment-side section or welding section. The triangle tip is arranged schneidringsegmentseitig. Tailoring segment and associated carrier body portion are then welded so that the two triangle tips are opposite. The triangle tips can be formed flattened. In addition, the triangle sides can also be formed more or less curved, so that in particular the already mentioned tulip-shaped cross-section can result. At each of the two sides of the opposite triangular tips, a wedge-shaped welding gap is formed, into which the weld seam is introduced. According to a particularly preferred embodiment, the root layer is welded through during welding in the region of the triangle tips.

The carrier body expediently consists of a common steel or of a common steel alloy. The steel matrix of the cutting element of the stationary tool is welded to the carrier body. Preferably, the welding is carried out as described above for welding the cutting ring or for welding the cutting ring segments.

The steel matrix of the cutting ring of the roller bit according to the invention is expediently a high-alloyed steel. The steel matrix of the cutting ring expediently contains 0.34 to 0.39 wt .-%, preferably 0.34 to 0.38 wt .-% and preferably 0.35 to 0.37 wt .-% carbon and expediently 0.85 to 1.80 wt .-%, preferably 0.9 to 1.75 wt.% and preferably 0.95 to 1.70 wt.% chromium. Furthermore, the steel matrix preferably contains 1.0 to 1.7 wt .-%, preferably 1.1 to 1.65 wt .-% and preferably 1.15 to 1.60 wt .-% silicon and 1.2 to 4, 0 wt .-%, preferably 1.25 to 3.95 wt .-% and preferably 1.35 to 3.90 wt .-% nickel. Furthermore, this steel matrix advantageously contains 0.18 to 0.33 wt .-%, preferably 0.20 to 0.31 wt .-% and preferably 0.21 to 0.30 wt .-% molybdenum and suitably 0.38 to 1 , 65 wt .-%, preferably 0.40 to 1.60 wt .-% and preferably 0.43 to 1.55 wt .-% manganese. In addition, this steel matrix expediently contains 0.02 to 0.18% by weight, preferably 0.02 to 0.16% by weight and preferably 0.03 to 0.15% by weight of aluminum and more preferably 0.01 to 0 , 05 wt .-%, preferably 0.01 to 0.04 wt .-% and preferably 0.01 to 0.03 wt .-% vanadium. The remainder of the steel matrix consists of iron and the weight percentages for carbon, chromium, silicon, nickel, molybdenum, manganese, aluminum, vanadium and iron must add up to 100 wt.% For a specific composition of the steel matrix.

According to a first preferred embodiment of the invention, the steel matrix contains the weight percentages given above for carbon, molybdenum and vanadium, and this steel matrix expediently contains 0.8 to 1.2 wt.%, Preferably 0.8 to 1.1 Wt .-%, preferably 0.9 to 1.05 wt .-% chromium and expediently 1.3 to 1.8 wt .-%, preferably 1.4 to 1.7 wt .-% and preferably 1.5 bis 1.6 wt .-% silicon and further advantageously 1.2 to 2.0 wt .-%, preferably 1.2 to 1.9 wt .-%, preferably 1.3 to 1.75 wt .-% nickel. The steel matrix according to this first embodiment furthermore advantageously contains 1.1 to 1.8% by weight, preferably 1.2 to 1.7% by weight, preferably 1.3 to 1.6% by weight of manganese, and 0, 01 to 0.08 wt .-%, preferably 0.02 to 0.07 wt .-%, preferably 0.03 to 0.06 wt .-% aluminum and the rest of the steel matrix of this first embodiment consists made of iron. Again, the wt .-% - have to add in each case to 100 wt .-%.

In a second preferred embodiment of the invention, the steel matrix also contains the weight percentages given above for carbon, molybdenum and vanadium and 1.3 to 1.9% by weight, preferably 1.45 to 1.8% by weight. %, preferably 1.55 to 1.75 wt .-% chromium and further 0.8 to 1.4 wt .-%, preferably 0.9 to 1.3 wt .-%, preferably 1.05 to 1.25 Wt .-% silicon. In addition, the steel matrix according to this second embodiment contains 3.5 to 4.2 wt .-%, preferably 3.6 to 4.1 wt .-%, preferably 3.75 to 4.0 wt .-% nickel and 0.25 to 0.65 wt.%, preferably 0.3 to 0.6 wt.%, preferably 0.35 to 0.55 wt.% manganese. In addition, the steel matrix of the second embodiment contains 0.1 to 0.18 wt%, preferably 0.11 to 0.17 wt%, preferably 0.12 to 0.16 wt% of aluminum and the remainder of the steel matrix consists of iron. It is understood that the wt .-% - information must add up to 100 wt .-% here.

The hardness of the steel matrix of the cutting ring is preferably 450 to 600 HV. Hardness of the steel matrix here means the hardness of the steel matrix alone, d. H. without carbide particles.

A very preferred embodiment is characterized in that the steel matrix of the cutting ring is potted with the hard metal particles. According to this embodiment, the production of the cutting ring thus takes place by casting. The carbide particles are poured into the steel matrix as it were. According to a preferred embodiment, the casting of the steel matrix takes place with the proviso that hard metal particles are present only or mainly in the wear-exposed surfaces of the steel matrix of the cutting ring.

It is within the scope of the invention that the proportion of hard metal particles in the cutting ring is more than 25% by volume, preferably more than 30% by volume and preferably more than 35% by volume. The rest of the cutting ring is formed in each case by the steel matrix. More preferably, more than 40% by volume, preferably more than 50% by volume, of hard metal particles are contained in the half of the cutting ring facing away from the carrier body or in the weld seam facing away from it.

Conveniently, the hard metal particles to at least 80 vol .-%, preferably at least 85 vol .-% and preferably at least 87 vol .-% of tungsten carbide, balance binder. Remaining binder means that the remaining vol, -% - content of at least one binder is formed. Thus, if according to a preferred embodiment of the invention, the hard metal particles from 90 vol .-% or from about 90 vol .-% tungsten carbide, they consist of 10 vol .-% or about 10 vol .-% of at least one Binder. The term tungsten carbide according to one embodiment of the invention means only actual tungsten carbide having the chemical formula WC. According to another embodiment of the invention, the term tungsten carbide also means tungsten carbide (WSC, WC / W ₂ C). Preferably, the binder for the cemented carbide particles is cobalt or substantially cobalt.

It is within the scope of the invention that the hard metal particles are introduced as hard metal granules in the steel matrix of the cutting ring, preferably poured. A particularly preferred embodiment of the invention is characterized in that the grain size of the hard metal particles is 1 to 10 mm, preferably 2 to 8 mm, preferably 2.5 to 7 mm and very preferably 3 to 6 mm. According to a particularly preferred embodiment of the Invention, the grain size of the hard metal particles is 3.5 to 5.5 mm. The hardness of the hard metal particles is suitably 800 to 1800 HV, preferably 1000 to 1600 HV and preferably 1400 to 1600 HV. It is understood that the components or the composition of the hard metal particles is selected so that the above-mentioned hardnesses can be adjusted.

The type of material produced according to the invention for the cutting ring is called "Metal Matrix Composites (MMC)" in English-speaking countries. In Germany, the term "hard material matrix composite material" is used. Such a material combines the "good" properties of at least two or more different materials.

The invention is based on the finding that a roller chisel according to the invention or the cutting ring of a roller chisel according to the invention is subject to surprisingly low wear. Accordingly, a tool change or cutting ring change must be made only after relatively long periods of time and to that extent considerable advantages are achieved compared to the known from the prior art roller bits. The invention is based in particular on the recognition that the cutting ring of a roller bit according to the invention not only has to have a high hardness but also sufficient toughness. The inventive design of the cutting ring an optimal compromise between the required hardness and the necessary toughness of the cutting ring is achieved. Furthermore, an inventively designed cutting ring can be brought by welding in a surprisingly strong bond with the carrier body. It must also be emphasized that the production of the composite between the cutting ring according to the invention and the carrier body is possible in a simple manner. Furthermore, it should be emphasized that the carrier body a roller bit according to the invention can be used repeatedly by a new cutting ring can be easily welded to the carrier body after prolonged use and appropriate wear. This too is a considerable advantage over known roller bits, which usually have to be completely replaced after the occurrence of signs of wear.

Fig. 1

eine Seitenansicht eines erfindungsgemäßen Rollenmeißels,

Fig. 2

ein einzelnes Schneidringsegment in einer Seitenansicht,

Fig. 3

das Schneidringsegment gemäß Fig. 2 im Querschnitt und ein zugeordneter Trägerkörperabschnitt im Querschnitt (vor der Verschweißung), und

Fig. 4

das Schneidringsegment und zugeordneter Trägerkörperabschnitt im Querschnitt nach der Verschweißung.

The invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. In a schematic representation:

Fig. 1

a side view of a roller bit according to the invention,

Fig. 2

a single cutting ring segment in a side view,

Fig. 3

the cutting ring segment according to Fig. 2 in cross section and an associated carrier body portion in cross section (before the welding), and

Fig. 4

the cutting ring segment and associated carrier body portion in cross section after the welding.

The FIGS. 1 to 4 show a roller bit for tunnel boring machines. This roller bit has a carrier body 1 and a circumferential over the circumference of the carrier body 1 cutting ring 2. The cutting ring 2 consists of a steel matrix 3 and hard metal particles 4 distributed therein. The hard metal particles 4 preferably consist of about 90% by volume tungsten carbide and about 10% by volume of a binder in the form of cobalt.

According to the invention, the cutting ring 2 consists of a plurality of over the circumference of the carrier body 1 successively arranged cutting ring segments 5. In the Fig. 1 was indicated that between the cutting ring segments 5 preferably gaps 6 are formed. Fig. 2 shows that a cutting ring segment 5 is formed bent and is positively adapted to the circumference of the carrier body 1. The length of a cutting ring segment 5 preferably corresponds to 1/10 or about 1/10 of the circumference of the cutting element 2.

According to the invention, cutting ring segments 5 are welded onto the carrier body 1. Fig. 3 on the one hand shows a cutting ring segment 5 and on the other hand the correspondingly assigned portion of the carrier body 1 prior to the production of the welded joint. It can be seen that the cutting ring segment 5 to be welded on has, on the carrier body side, two welding surfaces 7 tapering towards one another in cross-section obliquely to the center of the cutting ring segment 5 and towards the carrier body 1. Accordingly, the portion of the carrier body 1 assigned to the cutting-ring segment 5 to be welded on also has two welding surfaces 8 converging towards one another in cross-section obliquely to the center of the carrier body 1 and to the cutting-ring segment 5. Cutting ring segment 5 and associated carrier body portion each have a cross-sectionally approximately triangular or tulip-shaped welding section 10, 11. They are welded together with opposite triangular tips. Between the welding surfaces 7 and 8, the weld 9 is produced. Fig. 4 shows the finished welded joint between the cutting ring segment 5 and support body 1 with the weld 9 between the welding surfaces 7, 8. In the production of this weld the root pass is suitably welded through in the region of the triangle tips, which in Fig. 4 was hinted at. It should be noted, moreover, that expediently the carrier body side - in the embodiment In cross section triangular - Welding portion 10 of the cutting ring segment 5 is made of a different steel than the steel matrix 3, which receives the hard metal particles 4. It is within the scope of the invention that the welding section 10 consists of a weldable steel or of a good weldable steel.

In the Fig. 3 and 4 Incidentally, it can be seen that hard metal particles 4 are arranged homogeneously in the outer or wear-exposed area of a cutting ring segment 5. It is then within the scope of the invention that preferably more than 40% by volume, preferably more than 50% by volume, of hard metal particles 4 are present in the cutting ring segment 5 in this region. The hard metal particles 4 are arranged in a very preferred embodiment in the steel matrix 3 with the proviso that the hard metal particles 4 as possible have no direct contact with each other or that corresponding filled by the steel matrix distances between the hard metal particles 4th available. According to a particularly preferred embodiment, the hard metal particles 4 are introduced with the proviso in the steel matrix 3, that at least 90%, preferably at least 95% of the hard metal particles 4 have no direct contact with each other.

Claims (8)

1. Roller cone bit, more particularly for tunnel boring machines, with a carrier element (1) and with a cutting ring (2) connected to the carrier element (1) and extending over the circumference of the carrier element (1), wherein the cutting ring (2) comprises a plurality of cutting ring segments (5) arranged one behind the other over the circumference of the cutting ring (2), characterised in that the cutting ring (2) comprises a steel matrix (3) and hard metal particles (4) distributed therein,
   whereby the grain size of the hart metal particles is 1 mm to 10 mm,
   whereby the hard metal particles (4) consist of at least 70% by volume of tungsten carbide and at least one binding agent,
   and whereby the cutting ring segments (5) are welded onto the carrier element (1).
2. Roller cone bit according to claim 1 whereby the steel matrix (3) of the cutting ring consists of 0.35 to 0.37% by weight carbon, 0.95 to 1.70% by weight chromium, 1.15 to 1.60% by weight silicon, 1.35 to 3.9% by weight nickel, 0.21 to 0.30% by weight molybdenum, 0.43 to 1.55% by weight manganese, 0.03 to 0.15% by weight aluminium and 0.01 to 0.03% by weight vanadium as well as iron.
3. Roller cone bit according to claim 1 or 2 whereby the steel matrix (3) is cast with the hard metal particles (4).
4. Roller cone bit according to any one of claims 1 to 3, whereby the proportion of hard metal particles (4) in the cutting ring is more than 25% by volume, preferably more than 30% by volume and most preferably more than 35% by volume.
5. Roller cone bit according to any one of claims 1 to 4 whereby the hard metal particles (4) consist of at least 80% by volume, preferably at least 85% by volume and most preferably at least 87% by volume tungsten carbide, the remainder binding agent.
6. Roller cone bit according to any one of claims 1 to 5 whereby the binding agent of the hard metal particles (4) consists of cobalt.
7. Roller cone bit according to any one of claims 1 to 6 whereby the grain size of the hard metal particles (4) is 2 to 8 mm and preferably 2.5 to 7 mm.
8. Roller cone bit according to any one of claims 1 to 7 whereby the hardness of the hard metal particles (4) is 800 to 1800 HV, preferably 1000 to 1600 HV, most preferably 1400 to 1600 HV.

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