JP2021173113A - Abrasion resistant structure of excavating machine - Google Patents

Abstract

To provide high abrasion resistance to an excavation portion such as a casing tube, reduce the replacement cost by extending the life, and improve the function of the excavation portion.SOLUTION: A welded layer 41 made of metal solidified after melting and a cemented carbide abrasion-resistant layer 14 having a plurality of cemented carbide particles 42 held in a state of being completely buried inside the welding layer 41 and a plurality of cemented carbide particles 42 held in a state of being partially exposed from the welding layer 41 are formed on the high abrasion resistance surface 13 in an excavation portion of an excavating machine.SELECTED DRAWING: Figure 2

Description

The present invention relates to excavating machines such as casing tubes and buckets for heavy machinery used in, for example, all-casing construction methods.

There is a part where high frictional resistance occurs in the excavated part of the excavating machine. The portion is, for example, the tip surface of the first tube arranged at the tip of the casing tube or the outer peripheral surface of the tip portion. Further, a high frictional resistance is also generated in a portion of the casing bit provided at the tip of the casing tube on the outer peripheral side of the tip in the rotational direction. In the bucket of construction machinery, high frictional resistance due to excavation occurs against the tooth and side cutter.

If high frictional resistance continues to act, wear will naturally occur in that part. If wear makes it unusable, the excavation must be replaced with a new one.

Until now, there has been no attempt to improve wear resistance in excavated parts such as casing tubes and buckets.

In this regard, some casing bits fixed to the tip of the casing tube have a wear-resistant hardened overlay as disclosed in Patent Document 1 below. The hardened build-up layer is provided with a hardened build-up layer on the lower side surface of the hard blade (carbide tip) in the base metal. That is, the life of the casing bit is extended by improving the wear resistance of the base metal that supports the cemented carbide tip as much as possible.

However, since the hardened overlay layer has a structure that is thickened by welding, high wear resistance cannot be obtained.

Patent Document 2 below discloses a cutting bit having a built-up portion having cemented carbide particles on the lower portion of the cemented carbide tip on the surface of the bit body. Since the built-up portion of this bit has cemented carbide particles, which are grains of cemented carbide, the strength of the built-up portion itself is high, and abrasion resistance can be obtained for the portion supporting the cemented carbide tip.

Registered Utility Model No. 3100138 Japanese Unexamined Patent Publication No. 2019-203343

A main object of the present invention is to impart high wear resistance to the excavated portion, reduce replacement costs by extending the service life, and improve the function of the excavated portion.

The means for this is a welded layer made of metal solidified after melting, a plurality of cemented carbide particles held in a state of being completely buried inside the welded layer, and a plurality of cemented carbide particles on a high frictional resistance surface in the excavated portion of the excavating machine. It is a wear-resistant structure of an excavating machine in which a cemented carbide wear-resistant layer having a plurality of cemented carbide particles held in a state where a part of the welded layer is exposed is formed.

In this configuration, the tip surface on the tip side in the excavation direction or rotation direction of the excavation portion and the side surface portion adjacent to the tip surface, for example, the outer peripheral surface when the excavation portion has a cylindrical shape, are formed on a high friction resistance surface. The cemented carbide wear-resistant layer has high wear resistance and also functions as a blade. That is, the retained carbide particles exhibit wear resistance, and the cemented carbide particles partially exposed from the welded layer function as blades to assist the excavation action. In addition, the presence of cemented carbide particles eliminates internal defects such as blow holes that tend to form in the weld layer, obtains high adhesion between the cemented carbide particles and the weld layer, and improves the adhesion with the high friction resistance surface of the excavated part. do.

According to the present invention, since the ultra-hard wear resistant layer is provided on the high frictional resistance surface in the excavated portion of the excavating machine, high wear resistance of the portion that receives frictional force during excavation can be obtained, and the life of the excavated portion can be extended. It is possible to reduce the replacement cost by the above. Moreover, due to the high adhesion between the cemented carbide particles and the welded layer, the function as a blade of the cemented carbide particles can be fully exhibited.

Front view of the separated state at the tip of the casing tube. The front view which shows the neighborhood of a casing bit in a casing tube. Perspective view of the casing bit. Photograph of carbide particles. A photograph showing a cross section of a cemented carbide wear-resistant layer. The front view of the tip part of the casing tube which concerns on another example. The front view of the tip part of the casing tube which concerns on another example. Side view of the excavation part according to another example. Top view and side view of the tooth of FIG. Top view and side view of the side cutter of FIG.

An embodiment for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 shows a separated state of the tip side portion of the casing tube 11 as an example of the excavated portion of the excavating machine. FIG. 2 is an enlarged view of a main part of the tip side portion of the casing tube 11.

The casing tube 11 has a cylindrical shape, and a plurality of casing bits 12 are arranged at the tip thereof at intervals. The casing bit 12 is a part that functions as a blade during excavation, and is a replacement part that is replaced if it is damaged or worn.

Such an excavated portion has a carbide wear resistant layer 14 on the high friction resistance surface 13.

First, the schematic structure of the casing tube 11 will be described. As shown in FIG. 1, a plurality of concave portions 21 and convex portions 22 are alternately formed at regular intervals at the tip end portion of the casing tube 11, and are in the shape of a comb blade. The concave portion 21 and the convex portion 22 have a square shape when viewed from the front.

The recess 21 is a portion to which the holder 15 is fixed, and the casing bit 12 is detachably attached to the holder 15. The basic structure of the holder 15 and the casing bit 12 is the same as the existing one.

The state in which the casing bit 12 is attached to the recess 21 of the casing tube 11 is as shown in FIG. The holder 15 is fixed so as to be buried in the recess 21. The head portion 12a, which is the tip end portion of the casing bit 12, protrudes below the lower end surface of the holder 15 and also protrudes below the tip end surface of the casing tube 11.

The shape of the head portion 12a is a shape that points diagonally downward in the rotation direction of the casing tube 11 (see arrow A in FIG. 2), and at the tip thereof, a cemented carbide made of a cemented carbide that projects diagonally downward in the rotation direction. A hard tip 16 is provided. The casing bit 12 in the illustrated example is for clockwise rotation.

The above-mentioned high frictional resistance surface 13 is a portion where frictional resistance is particularly applied during the excavation action. In the case of the casing tube 11 as described above, the high friction resistance surface 13 has a tip surface (lower end surface) which is the tip in the excavation direction, an outer peripheral surface of a portion adjacent to the tip surface and extending to the rear in the excavation direction, and the tip thereof. It is a surface forming the outer peripheral side of the tip of the casing bit 12 attached to the above in the rotation direction.

Specifically, the example shown in FIG. 1 will be described specifically. The high friction resistance surface 13 has a cemented carbide wear-resistant layer 14 on the tip surface 22a of the convex portion 22 located at the tip of the casing tube 11 and the outer peripheral surface 23 of the tip portion. It has. The carbide wear-resistant layer 14 on the outer peripheral surface 23 of the tip portion is formed on the outer peripheral surface of the convex portion 22 and the upper portion behind the convex portion 22 in the excavation direction.

The carbide wear-resistant layer 14a on the tip surface of the convex portion 22 is formed on the entire surface. On the other hand, the carbide wear-resistant layers 14b, 14c, 14d formed on the outer peripheral surface 23 of the tip portion are formed linearly. The linear formation means that the convex portion 22 and the concave portion 21 are formed so as to draw a line, and the tip side contour line 14b that borders the convex portion 22 and the concave portion 21 and the diagonal line of the outer peripheral surface of the convex portion 22 are drawn. An additional line 14c and an annular rear end side contour line 14d extending horizontally behind the convex portion 22 and the concave portion 21 are formed.

The high frictional resistance surface 13 of the casing bit 12 is as follows. As shown in FIG. 3, which is a perspective view with the head portion 12a facing upward, the casing bit 12 has an outer surface 31 facing the outer periphery of the casing tube 11 and a right angle to the outer surface 31 and faces in the rotational direction. It has a tip surface 32. The high friction resistance surface 13 of the casing bit 12 having such a shape is a portion centered on the ridge line portion 33 connecting the tip surface 32 and the outer surface 31 of the head portion 12a. In this example, in particular, the portion 34 below the portion where the carbide tip 16 is exposed is used as the high friction resistance surface 13, and an integral carbide wear resistant layer 14e connected to the two surfaces is formed.

The cemented carbide wear-resistant layer 14 is composed of a welding layer 41 and carbide particles 42 added to the welding layer 41, as shown by enlarging a part in FIG. The welding layer 41 is formed by arc welding and is made of a metal solidified after melting.

The cemented carbide wear-resistant layer 14 is formed by dropping the cemented carbide particles 42 into iron melted by welding and causing them to settle. The carbide particles 42 that have entered the flow of molten iron are densely arranged with a small gap between them.

The cemented carbide particles 42 are grains made of cemented carbide, and at least a part of the cemented carbide particles 42, preferably all the cemented carbide particles 42 are spherical as shown in the photograph of FIG. The photograph of FIG. 4 shows a state in which a large number of cemented carbide particles 42 are collected. The particles in the photograph are carbide particles 42.

Here, the sphere shape does not mean only a perfect sphere, but means a shape like a sphere without sharp corners, and it is sufficient if the shape is a sphere or a shape close to it. The cemented carbide particles 42 are not obtained by crushing a waste cemented carbide, but are formed into a spherical shape by powder metallurgy.

The size of the cemented carbide particles 42 depends on the thickness of the cemented carbide wear-resistant layer 14, but is preferably smaller. If the size exceeds several mm, the gap between the cemented carbide particles 42 may become large and the integrity of the cemented carbide wear-resistant layer 14 may be lowered. However, if it is too small, workability when forming the carbide wear-resistant layer 14 may deteriorate. Therefore, the particle size of the cemented carbide particles 42 is preferably, for example, about φ0.5 mm to φ2 mm, and more preferably about φ0.5 mm to φ1.5 mm. The size of the cemented carbide particles 42 to be used may be unified or may vary.

When the size of the cemented carbide particles 42 is within the above range, the thickness of the cemented carbide wear-resistant layer 14 is preferably around 3 mm, for example.

When the cemented carbide particles 42 are added to the welding layer 41, a plurality of cemented carbide particles 42a held in a state of being completely buried inside the welding layer 41 and a plurality of cemented carbide particles 42a held in a state of being partially exposed from the welding layer 41. Carbide particles 42b are provided. Even if the cemented carbide particles 42a are entirely buried, when the cemented carbide wear-resistant layer 14 is worn by the excavation action, the cemented carbide particles 42b may be partially exposed from the welding layer 41.

Further, the density of the cemented carbide particles 42 is higher on the lower layer side of the cemented carbide wear resistant layer 14 than on the upper layer side.

FIG. 5 shows a cross-sectional photograph of the actually manufactured carbide wear-resistant layer 14. As shown in this photograph, the cemented carbide wear-resistant layer 14 is composed of spherical carbide particles 42, and many cemented carbide particles 42 are densely arranged and dense.

In the casing tube 11 configured as described above, since the carbide wear-resistant layer 14 is formed on the casing tube 11 itself and the required high friction resistance surface 13 of the casing bit 12, the respective carbide wear-resistant layers 14 are formed. However, the wear resistance of that part is improved to extend the life of each part. That is, the life of the casing bit 12 which is a replacement part can be extended, and at the same time, the life of the casing tube itself which is not a replacement part can be extended.

Moreover, the cemented carbide wear-resistant layer 14 composed of the welded layer 41 made of solidified metal and the cemented carbide particles 42 in which all or part of the cemented carbide particles 42 is held is higher in wear resistance due to the cemented carbide particles 42. Has. Further, in general, the weld layer 41 may have an internal defect such as a blow hole, but since the weld layer 41 is formed while the cemented carbide particles 42 are settled, as shown in the photograph of FIG. A defect-free welding layer 41 can be obtained, and high adhesion between the welding layer 41 and the cemented carbide particles 42 can also be obtained. Further, the adhesion between the carbide wear resistant layer 14 and the high friction resistance surface 13 is also good. Therefore, the wear resistance of the carbide wear resistant layer 14 is extremely high.

As a result, the material cost required for parts replacement and the labor required for replacement can be significantly reduced.

Further, some of the cemented carbide particles 42 added to the welding layer 41 are partially exposed, and in particular, the cemented carbide particles 42b function as blades. The carbide particles 42b exposed as the carbide wear-resistant layer 14 wears down as it is used also function as a blade. Therefore, it assists excavation by the casing tube 11. That is, since the part of the casing bit 12 that is the original blade that comes into strong contact with the excavation can also have a function as a blade, the workability of excavation is improved, and the load is reduced and the workability is improved as a whole. It is measured.

In addition, since the casing tube 11 itself has an excavation function, the load on the casing bit 12 during the excavation work can be reduced, and from this point as well, the durability of the casing bit 12 can be expected to be improved.

Other examples will be described below. In this description, the same parts as those described above are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 6 is a front view of a main part of the casing tube 11 according to another example. The casing tube 11 has a planar cemented carbide not only on the tip surface 22a of the convex portion 22 but also on the outer peripheral surface 23 of the tip portion. The wear-resistant layer 14 is provided.

In the casing tube 11 having this configuration, since the carbide wear-resistant layer 14 is all planar, the wear resistance can be further improved.

FIG. 7 is a front view of a main part of the casing tube 11 according to another example, and the casing tube 11 is in the excavation direction from the carbide wear resistant layers 14b, 14c, 14d formed on the outer peripheral surface 23 at the tip portion. A cemented carbide wear-resistant layer 14f is also formed in a portion extending to the rear of the surface. Specifically, the cemented carbide wear-resistant layer 14f to be added has a form of extending diagonally along the rotation direction of the casing tube 11, and a plurality of the cemented carbide wear-resistant layers 14f are provided at intervals along the circumferential direction.

Further, the carbide wear-resistant layer 14a on the tip surface 22a of the casing tube 11 and the carbide wear-resistant layers 14b, 14c, 14d on the outer peripheral surface 23 of the tip portion are directly formed on the high friction resistance surface 13. The carbide wear-resistant layer 14f, which extends diagonally when added, is indirectly formed. That is, as shown in FIG. 7, the carbide wear-resistant layer 14f is formed on one surface of the strip-shaped plate member 45, and the plate member 45 is fixed to the outer peripheral surface 23 of the tip portion which is the high friction resistance surface 13. ing. It can be fixed by welding or the like.

In the casing tube 11 having this configuration, since the portion of the outer peripheral surface 23 extending to the rear in the excavation direction can also have a function as a blade, it contributes to better excavation as well as improving wear resistance. Moreover, since the cemented carbide wear-resistant layer 14f is provided not directly on the high friction resistance surface 13 but via a separate plate member 45, it is easy to form the desired cemented carbide wear-resistant layer 14 extending in a spiral shape. You can.

FIG. 8 shows an example in which the excavation part of the excavating machine is a bucket 51 of a heavy machine. That is, an example is shown in which the carbide wear-resistant layer 14 is formed on the tooth 52, which is a claw in the bucket 51, and the high friction resistance surface 13 of the side cutter 53 provided at a position close to the tooth 52 on both sides of the bucket 51. There is.

9 is a plan view (FIG. 9 (a)) and a side view (FIG. 9 (b)) of the tooth 52, and FIG. 10 is a plan view (FIG. 10 (a)) and a side view (FIG. 10 (b)) of the side cutter 53. )).

As shown in these figures, the carbide wear-resistant layer 14 is formed as a series on the surface of the tip edges 52a and 53a and the peripheral edges 52b and 53b continuous thereto.

According to this configuration, not only the wear resistance can be improved, but also unprecedented excavation performance can be imparted.

The above configuration is a configuration for carrying out the present invention, and the present invention is not limited to the above-mentioned configuration, and other configurations may be adopted.

For example, the excavation part of the excavation machine may be a heavy machine, a construction machine, or the like other than those described above.

Further, as the cemented carbide particles 42 used for forming the cemented carbide wear-resistant layer 14, those other than spherical ones, for example, those obtained by crushing may be used. In this case, it is preferable to add it to the upper layer side rather than the lower layer side.

11 ... Casing tube 12 ... Casing bit 13 ... High friction resistance surface 14 ... Carbide wear resistant layer 41 ... Welding layer 42 ... Carbide particles 45 ... Plate material 51 ... Bucket 52 ... Tooth 53 ... Side cutter

Claims (7)

A welding layer made of metal solidified after melting, a plurality of cemented carbide particles held in a state of being completely buried inside the welding layer, and one from the welding layer on a high friction resistance surface in the excavation part of the excavation machine. A wear-resistant structure of a drilling machine in which a cemented carbide wear-resistant layer having a plurality of cemented carbide particles held in an exposed state is formed. The wear-resistant structure of an excavating machine according to claim 1, wherein the cemented carbide wear-resistant layer is formed on a replacement part as the excavated portion. The carbide wear-resistant layer is formed on the plate material,
The wear-resistant structure of an excavating machine according to claim 1, wherein the plate material is fixed to the high frictional resistance surface. The wear-resistant structure of an excavating machine according to any one of claims 1 to 3, wherein at least a part of the cemented carbide particles has a spherical shape. The wear-resistant structure of an excavating machine according to any one of claims 1 to 4, wherein the lower layer side of the cemented carbide wear-resistant layer has a higher density of the cemented carbide particles than the upper layer side. A casing tube in which a plurality of casing bits are arranged at intervals at the tip.
A welded layer made of metal solidified after melting, a plurality of cemented carbide particles held in a state of being completely buried inside the welded layer, and a plurality of cemented carbides held in a state of being partially exposed from the welded layer. A casing tube in which a cemented carbide wear-resistant layer having hard particles is formed on a portion of the tip surface between the casing bits and an outer peripheral surface of the tip portion. The cemented carbide wear-resistant layer is also formed at a portion from the cemented carbide wear-resistant layer formed on the outer peripheral surface of the tip portion to the rear in the excavation direction.
The casing tube according to claim 6, wherein the cemented carbide wear-resistant layer extends obliquely along the rotation direction of the casing tube, and a plurality of the carbide wear-resistant layers are provided along the circumferential direction.

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