JP2510379Y2 - Shield excavator fishtail bit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a fish tail bit mounted in the center of a cutter head of a shield machine.

[Prior Art] In a sealed shield machine such as an earth pressure type and a mud type, an excavation bit called a fish tail bit is attached to the center of the cutter head.

Fig. 5 shows an example of a muddy water shield machine.
A fishtail bit 1 in the shape of a pentagonal plate similar to a fish tail is attached to the center of the face plate of a cutter head 6 that rotates left and right, and core drilling is performed prior to the teeth bit 5 to promote excavation of the facet. To do. Illustrated axis XX
Is the center of rotation of the cutter head 6 and the fish tail bit 1.

6 to 12 show conventional examples of fish tail bits for muddy water shields. As shown in these figures, a fish tail bit 1 is composed of a base material 1a made of general structural carbon steel or high-strength steel, a cemented carbide tip 2 and a base material implanted in the peripheral edge of the base material 1a on the face side. It is composed of a hard overlay 4 that protects 1a and imparts wear resistance. When excavating cohesive soil or sandy soil by changing the height of the cemented carbide tip 2 depending on the excavation soil quality, see FIG. As shown in FIG. 8, a carbide tip 2a having a height h ₁ and a thickness t ₁ is provided on a side substantially parallel to the rotation center axis XX and a side oblique to the axis XX. It was planted. The above-mentioned height dimension h ₁ was about 20 mm evenly in each part for one fish tail bit, and the thickness dimension t ₁ was also set to 10 to 20 mm uniformly in each part. In the case of excavating the gravel layer, as shown in FIGS. 9 to 12, a corner portion 1b where a side substantially parallel to the rotation center axis XX and a side oblique to the axis XX intersect. The height dimension h ₂ of the cemented carbide tip 2b to be planted in is approximately twice the height dimension h ₁ of the cemented carbide tip 2a (about 40 m
m) Also in the cemented carbide tip 2b for this gravel layer, the thickness dimension t ₂ is the thickness dimension t ₁ of the ordinary cemented carbide tip 2a.
Was similar to.

[Problems to be solved by the device]

In recent years, the shield construction for deep depth and long distance excavation is increasing, and in urban areas it is often difficult to acquire land, so it is often necessary to excavate under bad soil conditions such as gravel layer. As for the above, it has become necessary to further improve wear resistance.

Looking at the wear form of the fish tail bit, it can be seen that wear progresses from the corner portion 1b, as shown in FIGS. 13 to 18. In other words, the corner portion 1b of the fishtail bit must handle both excavation on the front surface in the traveling direction and the outermost peripheral portion, and the sliding distance is long compared to the portion close to the rotation center axis XX. However, due to the high resistance of the ground, even though the progress of wear is several times faster,
Conventionally, this has not been fully taken into consideration.
Especially, in the fish tail bit for gravel, even if only the height of the cemented carbide tip 2b to be implanted in the corner is increased,
Since the thickness is the same, the speed of wear does not change, and only the service life increases as the height increases, which limits the life of the entire fish tail bit.

In view of the above points, the present invention has an object to improve the wear resistance of the corner portion of the fish tail bit to the same level as the other portions and extend the entire life.

[Means for solving the problem]

In order to achieve the above object, the present invention is attached to a central portion of a cutter head, and a cemented carbide tip is implanted on a side substantially parallel to the rotation axis of the cutter head and a side oblique to the rotation axis. In the fish tail bit, at the corner portion where the side substantially parallel to the rotation axis and the side oblique to the rotation axis intersect, the thickness is larger than that of the cemented carbide tip implanted at a portion other than the corner portion. It is characterized by implanting a cemented carbide chip having a large height and a large height.

[Action]

When the thickness of the cemented carbide tip is increased, the wear rate of the tip decreases under the same excavation conditions, and the progress of wear can be suppressed. Therefore, by making the thickness and height of the cemented carbide tip to be implanted in the corner portion of the fish tail bit larger than those of the cemented carbide tip to be implanted in other portions, the corner portion can be made equivalent to other portions. It becomes possible to have a service life.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 is a front view, FIG. 2 is a side view, FIG. 3 is a sectional view taken along the line AA, and FIG. 4 is a sectional view taken along the line BB. Reference numeral 1 is a fish tail bit attached to the central portion of the cutter head of a muddy water shield machine, and XX shown in FIG. 2 is a rotation center axis.

1a is a base material made of general structural carbon steel or high-strength steel, and has an angle of intersection between a side substantially parallel to the rotation center axis XX and a side oblique to the center axis XX. A cemented carbide tip 3 constructed by applying the present invention is implanted in the portion 1b, and the portions other than the corner portion 1b are similar to or similar to the cemented carbide tip 2 of the conventional example (FIG. 8). Carbide chip 2 of is implanted. The cemented carbide tip 2 and the cemented carbide tip 3 of this embodiment are mainly made of tungsten carbide equivalent to JISE5. Reference numeral 4 is a hard overlay for protecting the base material 1a and imparting abrasion resistance.

The cemented carbide tip 3 to be implanted in the corner portion 1b has a larger thickness and height than the cemented carbide tip 2 to be implanted in a portion other than the corner. If concrete values are shown, the cemented carbide tip 2 has a thickness t _{1 of} about 10 to 20 mm and a height h ₁ of about 20 mm, like the ordinary cemented carbide tip 2a shown in FIGS. 6 to 8. For the cemented carbide tip 3, the thickness t ₂ of the ordinary cemented carbide tip 2a is 1.
Use the one that is 5 times or more and has a height h _{2 that} is twice or more that of the ordinary carbide tip 2a. Further, if the width (planting range) w of the cemented carbide tip 3 to be implanted in the corner portion 1b is also increased according to the excavation soil quality and the excavation distance, the wear resistance of this portion is further improved.

INDUSTRIAL APPLICABILITY The present invention can be applied not only to the muddy water type shield but also to all fish tail bits of various shield excavators.

[Effect of device]

The fish tail bit of the present invention not only makes the height of the carbide tip of the corner portion responsible for excavation of the front surface and the outermost peripheral portion in the traveling direction larger than the height of the carbide tip of the other portion, but also of the corner portion. Since the thickness of the carbide tip is also made larger than the thickness of other portions of the carbide tip, the progress of wear is suppressed,
It is possible to extend the service life of the corner portion to the same level as that of the non-corner portion and extend the entire life, and it is also possible to cope with long-distance excavation in soil with bad wear conditions such as a gravel layer. Moreover, expensive carbide chips can be used appropriately according to the difference in excavation conditions of each part, which is economical.

[Brief description of drawings]

FIG. 1 is a front view of a fish tail bit for a muddy water shield which is an embodiment of the present invention, FIG. 2 is a side view with a part thereof cut away, and FIG. 3 is a sectional view taken along the line AA of FIG. FIG. 4 is a sectional view taken along the line BB, FIG. 5 is a side sectional view of a muddy water shield machine equipped with a fish tail bit, and FIG. 6 is a front view of a conventional fish tail bit for cohesive soil / sandy soil. , FIG. 7 is a side view with a part cut away, and FIG. 8 is C of FIG.
-C sectional view, FIG. 9 is a front view of a conventional fish tail bit for gravel, and FIG. 10 is a side view with a part thereof cut away.
FIG. 11 is a sectional view taken along the line DD of FIG. 10, FIG. 12 is a sectional view taken along the line E-E of FIG. 10, and FIG. 13 is a front view showing a worn form of a conventional fish tail bit for cohesive soil / sandy soil, and FIG. The figure shows the side view,
FIG. 15 is a sectional view taken along line F-F of FIG. 14, FIG. 16 is a front view showing a worn form of a conventional fish tail bit for gravel, and FIG.
FIG. 18 is a side view thereof, and FIG. 18 is a sectional view taken along line GG of FIG. 1 ... Fish tail bit, 1a ... Base material, 1b ... Corner part, 2 ... Carbide chip implanted in other peripheral edge,
3 ...... angle carbide chip implanted in the part 1b of, 4 ...... hard build-up, 6 ...... cutter head, t ₁ ...... carbide tips of 2 thickness, of h ₁ ...... carbide tips 2 Height, t ₂ …… thickness of the carbide tip 3, h ₂ …… height of the carbide tip 3, w …… carbide tip 3
Width (planting range).

Claims (1)

(57) [Scope of utility model registration request] 1. A fish tail which is attached to the center of a cutter head of a shield machine and has cemented carbide chips implanted in a side substantially parallel to the rotation axis of the cutter head and a side oblique to the rotation axis. In the bit, at a corner where a side substantially parallel to the rotation axis and a side oblique to the rotation axis intersect, a thickness dimension and a thickness dimension more than those of a cemented carbide tip implanted in a portion other than the corner portion. A fish tail bit for shield machine, which is characterized by implanting a carbide tip with a large height.