JP7249701B1 - roller cutting bit - Google Patents

Abstract

The object of the present invention is to enable a tunneling machine to reliably cut and remove underground obstacles in a jacking method or the like. A roller-type cutting bit (10) rotatably attached to a cutter head (1) on the front surface of an excavator is provided along a ridgeline of a ridge portion (21) intermittently set along a circumferential direction. The roller-type cutting bit 10 is provided with a plurality of rows of the ridge arrangement portion 20 having a plurality of chips 30 arranged along the width direction intersecting the circumferential direction. The ridges arranged portions 20, 20 adjacent to each other in the width direction are set such that the azimuths in which the ridges 21 are set are shifted in the circumferential direction. [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a roller-type cutting bit used in a tunneling machine applied to a jacking method or a shield method in tunnel construction.

2. Description of the Related Art A plurality of cutter bits are attached to a cutter head on the front surface of an excavator used in a jacking method or a shield method (hereinafter referred to as jacking method, etc.). Cutter bits are broadly classified into fixed cutting bits for cutting sand, clay, and relatively small gravel ground, and roller-type cutting bits for cutting large stones and bedrock.

The main type of fixed cutting bit is a type in which cemented carbide tips mainly composed of tungsten carbide, which is hard and has excellent wear resistance, are embedded in various shapes. However, since it is vulnerable to impact, there is a problem that the cemented carbide tip breaks when it comes into contact with a huge stone or the like. In addition, a fixed cutting bit generates a large cutting resistance, especially when cutting hard ground. Therefore, the excavator is required to have a very large rotational torque, and the excavator main body requires a reaction force equal to or greater than the rotational torque in order to prevent rolling. Furthermore, since the fixed cutting bit accelerates the wear of the cemented carbide tip, it is necessary to reduce the cutting resistance between the cutting bit and the ground when excavating the ground or bedrock where boulders are present. For this reason, in the above-mentioned megalithic ground and bedrock, it is common to use a roller-type cutting bit in which the cutting bit rotates in an excavator used in a jacking method or the like.

As a roller type cutting bit, for example, there is one described in Patent Document 1. A plurality of roller-type cutting bits are rotatably attached to the cutter head on the front surface of the excavator. The cutter head is pressed against the ground, and the roller-type cutting bit rotates due to the reaction force accompanying the rotation of the cutter head, cutting the ground and splitting the rock. The roller-type cutting bit is composed of a plurality of rows of annular ridges formed along the direction of rotation and cemented carbide chips embedded in the circumferential direction along the ridge lines of the ridges. there is In addition to the roller-type cutting bits, a plurality of fixed cutting bits are immovably attached to the cutter head. Rotation of the cutter head causes the fixed cutting bit to chip away the ground.

Japanese Patent Application Laid-Open No. 2014-201975 (see FIGS. 1, 7, 8, etc.)

By the way, in the jacking method and the like, in order to avoid obstacles left in the ground, for example, there is a method of excavating openly from the ground to remove the obstacles. In addition, if the obstacle is an earth retaining pile or supporting pile that is integrated with the structure on the ground, there is a method to avoid the obstacle by providing a horizontal curve or a vertical curve in the excavation route such as jacking method. Common.

The method of excavating from the ground to remove objects involves excavation work, ground improvement work, relocation work of buried objects, and the like, which greatly affects cost, construction period, and surrounding environment. Furthermore, there are many underground obstacles integrated with structures that cannot be removed from the ground. Also, avoidance by changing the excavation route is often unavoidable if other buried objects are adjacent or if it is technically difficult to provide curves in front and behind. Furthermore, even if it is possible to avoid obstacles, it is necessary to introduce special facilities and equipment to avoid obstacles, and to secure materials for new pipelines to enable construction of curved lines before and after. This may have a significant impact on cost and construction period. Furthermore, if an obstacle is to be avoided by introducing a vertical curve in the front and rear, it may not be applicable to sewage pipes that are basically constructed with a natural slope. Obstacles left in the ground are not always known in advance, and there are cases where obstacles that are not recorded are encountered, and obstacles that are not known in advance should be avoided. Since it is impossible to do so, it has to be dealt with from the ground. For this reason, a construction method that can be constructed without removing the obstacles from the ground side and without changing the excavation route is expected.

In this respect, if a conventional roller-type cutting bit as in Patent Document 1 is used to penetrate an obstacle without changing the excavation route, fragments of the obstacle cut by the cutter head are It may get stuck in the troughs between the protrusions of the roller type cutting bit, hindering subsequent cutting and discharge of the cut material. If such an obstacle occurs, it is necessary to stop the construction work, move the excavator backward, and then remove the debris. If construction is interrupted frequently, the work process will be delayed and the work cost will increase, which is not preferable.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to enable a tunneling machine to reliably cut and remove underground obstacles in a jacking method or the like.

In order to solve the above-mentioned problems, the present invention provides a roller-type cutting bit rotatably attached to a cutter head on the front surface of an excavator. and a plurality of chips provided along the ridgeline of the ridges are provided in a plurality of rows along a width direction intersecting the circumferential direction, and the ridges adjacent to each other in the width direction are separated from each other by the It is possible to employ a configuration in which the azimuths in which the ridges are set are shifted in the circumferential direction.

Further, it is possible to employ a configuration in which grooves are formed longitudinally along the circumferential direction and concavely recessed between the ridges adjacent to each other in the circumferential direction.

INDUSTRIAL APPLICABILITY This invention makes it possible to reliably cut and remove underground obstacles with a tunneling machine in a jacking method or the like.

Front view of cutter head with roller cutting bit II-II sectional view of Fig. 1 Partially cut front view of the roller type cutting bit used in the central part IV-IV sectional view of Fig. 3 Front view of roller type cutting bit used in the central part VI-VI sectional view of Fig. 5 (only the main part is enlarged) Perspective view of a roller type cutting bit used in the central part Front view of roller type cutting bit used for edge IX-IX cross section of Fig. 8 Longitudinal cross section of excavator

An embodiment of the invention will be described with reference to the drawings. FIG. 1 is a front view showing a cutter head 1 of an excavator S used in a jacking method or the like according to an embodiment of the present invention, and FIG. 2 is a right side view thereof. 3 to 9 show details of the roller type cutting bit 10 attached to the cutter head 1. FIG.

The excavator S is composed of a shield body 2 housed in a cylindrical casing 3, as shown in FIGS. A shield body 2 is thrown into the ground from a starting shaft set somewhere on an excavation route and laterally propelled toward a reaching shaft. For propulsion, a hydraulic jack is usually used near the launch shaft. By pressing the hydraulic jack, the propulsion pipe C connected to the rear end side is propelled together with the excavator S (see FIG. 10). Reinforced concrete pipe bodies and the like are often used for the propulsion pipe C, but steel pipes, cast iron pipes, and the like may also be used depending on the specifications of the pipeline.

As shown in FIG. 10, the excavator S is provided with a partition B, and the partition B partitions the ground side at the front end and the propulsion pipe C at the rear end. A bearing mechanism 5 is attached to the partition wall B, and a shaft 6 passes through the partition wall B via the bearing mechanism 5 . A cutter arm 4 is provided at the tip of the shaft 6 . A cylindrical cutter disk 7 and a front plate 8 closing the front surface of the cutter disk 7 are connected to the cutter arm 4 . A plurality of roller-type cutting bits 10 are rotatably attached to the front plate 8 (see FIGS. 1 and 2). The roller-type cutting bit 10 has a support shaft 13 (see FIGS. 3 and 4) that protrudes sideways and is supported by a bearing (not shown) provided on the front plate 8. free to rotate. Hereinafter, this roller type cutting bit 10 is simply referred to as the roller bit 10, the direction of rotation about the axis of the roller bit 10 is the "circumferential direction", and the direction of the support shaft 13 of the roller bit 10 (the direction intersecting the circumferential direction) is It is called "width direction".

The excavator S has a directional control jack, and apart from this, a slow speed equipment cylinder P is provided between the excavator S and the propulsion pipe C. As shown in FIG. The slow-speed equipment cylinder P is provided with a low-speed propelling jack J, and the low-speed propelling jack J is controlled so that the extension speed of the rod is about 0.1 mm per minute. The rod of the low-speed propelling jack J extends and the cutter head 1 is pressed against the ground. coincides with the axis of the propulsion tube C to rotate). The roller bit 10 is rotated around the axis of the support shaft 13 by the reaction force accompanying the rotation of the cutter head 1, and cuts the ground and splits the rock. In addition to the roller bit 10, a plurality of fixed cutting bits 40 (see FIG. 1) are immovably attached to the cutter head 1, so that when the cutter head 1 rotates, the fixed cutting bits 40 also scrape off the ground. go. The fixed cutting bit 40 is composed of a plate-shaped cutting edge as in the conventional example. Earth and sand, rock masses, and the like generated by excavation of the ground are discharged through the mud discharge pipe D to the starting shaft side.

Here, in the present invention, the roller bit 10 cuts and removes obstacles in the middle of the route for constructing the new pipeline, such as earth retaining piles, supporting piles, and other remaining objects buried in the underground space. After that, we have adopted the one with the function to continue the excavation. In this regard, the conventional roller bit could not exhibit such a function.

(Development process of the roller bit 10 of this invention)
With a conventional roller bit, when cutting an obstacle in the ground, if a part of the obstacle is cut in a large chunk, the cut chunk of the obstacle will get caught in the roller bit, causing the cutter head to stop. cutter lock) occurred. In addition, the cutter lock causes the excavator to roll, and the impact on the roller bit attached to the cutter head causes the cemented carbide tip embedded along the outer periphery of the roller bit to break. rice field. In addition, if the obstruction block that is caught is of a size that cannot be ejected from the excavator, there is a concern that subsequent continuous excavation will be impossible. Therefore, in the development process of the present invention, the first problem was to be able to subdivide and cut the obstacles to a size that can be discharged together with the excavated soil.

In general, when trying to cut an obstacle with a bit, there is a problem that the cemented carbide tip wears out quickly and the wear limit is exceeded in an early stage, making cutting impossible. In addition, there is a possibility that the cemented carbide tip may be damaged due to impact caused by coming into contact with an unexpected obstacle during excavation. In such cases, it is necessary to replace the bit attached to the cutter head in the ground. However, in order to replace the bit, it is necessary to use an excavator with a special structure that allows an operator to work inside the shield body 2 and a special cutter head that allows the bit to be replaced from inside the machine. In addition, the need for auxiliary construction methods such as ground improvement will greatly affect the cost and construction period. For this reason, we emphasized high durability (slow wear of the carbide tip) as the second issue.

Furthermore, if a large vibration occurs during cutting of an obstacle, if the obstacle is integrated with an upper structure, there is a concern that the structure itself will be affected. Furthermore, there is concern that noise and vibration will affect the surrounding environment. For this reason, as a third issue, when cutting obstacles, it is important to reduce vibration and noise as much as possible.

By the way, in the conventional roller bit shown in Patent Document 1, crests and troughs are alternately arranged along the width direction along the entire circumference, and chisel-shaped carbide chips are embedded in the crest portion along the circumferential direction. is As a result of experiments using this roller bit, we found that the obstacles were left uncut in the valleys between the ridges, and that there were large arc-shaped obstacles in the valleys of the roller bit along the circumferential direction. The result was that a lump remained (bite). As a result, in the initial stage of development, in order to subdivide and cut obstacles, the roller bit should be arranged so that the cutting trajectory is maintained at nearly the same height over the entire cross section (entire circumference). I thought that it was necessary to cut with a surface like a "file" as much as possible. For this reason, a specially shaped roller bit with a sharp chisel tip protruding radially outward was embedded in the groove of the roller bit, and an experiment was conducted to cut steel sheet piles.

However, with this prototype roller bit, although the steel sheet pile was penetrated as a result, chipping of the chisel tip partially embedded in the valley portion of the roller bit was found here and there. Since this phenomenon was not confirmed with other roller bits that do not cut the joints (sections) of the steel sheet pile, the cause of the chipping of the chisel tip was that the joints of the steel sheet piles were flexible and the chisel tip was bitten into. It was speculated that the steel sheet pile moved and was damaged due to the recoil when returning. Based on the results of this experiment, it was determined that a tip insert structure in which a carbide tip is embedded in the base material of a roller bit, rather than a structure like a chisel tip, is optimal for cutting obstacles by subdividing them.

On the other hand, in order to subdivide and cut obstacles, we initially thought that it was necessary to arrange the cutting trajectory of the same height over the entire cross section (full width) as a function of the roller bit. . However, if the intervals between the crests of the rabbit are made as narrow as technically possible, the troughs are almost eliminated. In this case, it is difficult to cut obstacles in valleys where there are no cemented carbide chips. For this reason, it was found that when the mountain part penetrates the steel plate, which is an obstacle, a phenomenon occurs in which the steel plate is pushed in at the valley part. For this reason, assuming a tip insert structure in which carbide tips are embedded, the space between the ridges of the roller bit is made as narrow as possible, and the thickness of the steel plate, which is an obstacle, can be penetrated by the ridges. We investigated a specially shaped roller bit with a deep structure for the valley part.

Regarding the pitch of the crest portion of the roller bit, in order to secure the cutting locus over the entire cross section (entire width), as a result of examination from the cutting locus development diagram, it was determined that a pitch of 20 mm, for example, is suitable. Also, in order to prevent obstacles from being pushed into the valley portion, it was thought that it was necessary to secure a depth of 20 mm, for example. However, if these two conditions were to be met, the processing of the roller bit would be too precise, and it would be difficult to manufacture the roller bit in terms of precision and structure.

From the above, in the prototype of the present invention, unlike the mountain of the conventional roller bit, the protrusion provided with the carbide tip is continuously provided over the entire circumference. A plurality of ridges (protrusions) are divided along the circumferential direction, and they are intermittently arranged in the circumferential direction. As a result, along the circumferential direction, the ridge portions having the chip insert structure and the trough portions having no chips were alternately arranged. In addition, when a specific azimuth around the axis of the roller bit is viewed from the outer diameter direction toward the axial direction, adjacent rows are arranged so that the crests and troughs are alternately arranged. As a result, good results were obtained with respect to cutting of underground obstacles and discharge of the cuttings. A specific configuration of the present invention will be described below.

(Structure of roller bit 10 of the present invention)
The roller bit 10 shown in the embodiment includes a central roller bit 11 shown in FIGS. 3 to 7 and an edge roller bit 12 shown in FIGS. The central roller bit 11 is fixed to the central portion of the cutter head 1 near the axis, and the end roller bit 12 is fixed near the outer edge of the cutter head 1 far from the axis. The central roller bit 11 and the end roller bit 12 are different in the number of rows of peaks and valleys (the number of rows of the protrusion arrangement portion 20 to be described later), but have the same basic configuration. . For this reason, the configuration of the roller bit 10 of this embodiment will be described below using the central roller bit 11 as an example. The number of rows of ridges and troughs set on the roller bit 10 can be freely increased or decreased according to the situation of obstacles, construction conditions, and the like.

As shown in FIGS. 3 to 7, the roller bit 10 has a ridge portion 21 intermittently set along the circumferential direction and a plurality of chips 30 provided along the ridgeline of the ridge portion 21. have. As the tip 30, a cemented carbide tip is usually used. In addition, grooves 22 formed longitudinally along the circumferential direction and recessed in a concave shape are formed between the ridges 21, 21 adjacent along the circumferential direction. Here, an annular region formed by the protrusions 21 and the grooves 22 that are alternately arranged along the circumferential direction is referred to as a protrusion arrangement portion 20 . In the central roller bit 11 shown in FIGS. 3 to 7, the ridge-arranged portions 20 are arranged in eight rows in the width direction, and in the end-portion roller bit 12 shown in FIGS. is set to 3 columns.

A further outer region of the protrusion arrangement portion 20 located on the outermost side serves as a shoulder portion 19a connected to the end surface of the outer member 19 in which the protrusion portion 21 and the groove portion 22 are formed. The end roller bit 12 having a small number of rows of the protrusions 20 has a shoulder portion 19a that is slightly wider than the central roller bit 11. As shown in FIG. Reference numeral 14 in the drawing denotes a bolt for coaxially fixing the support shaft 13 to a core member 18 corresponding to the axial center of the roller bit 10 . A reference numeral 15 denotes a seal 15 provided between the support shaft 13 and the outer member 19 . A reference numeral 16 denotes a bearing 16 that supports the core member 18 and the outer member 19 so as to be rotatable about their axes. Reference numeral 17 denotes a bearing 17 that supports the support shaft 13 and the outer member 19 so as to be rotatable about their axes.

In this embodiment, as shown in FIG. 4 , in one protrusion arrangement portion 20, the direction (central angle) L1 in which the protrusion portion 21 is set and the direction (center angle) L1 in which the groove portion 22 is set are set. corners) L2 are alternately arranged along the circumferential direction. Between the azimuth (central angle) L1 of the protrusion 21 and the azimuth (central angle) L2 of the groove 22, a slight gap of the azimuth (central angle) L0 is set. The orientations (central angles) L1 of all the protrusions 21 are set to be the same, the orientations (central angles) L2 of all the grooves 22 are set to be the same, and the orientations (central angles) L0 of all the gaps are set to be the same. It is desirable to be However, it does not prevent the orientations (central angles) L0 of the gaps from being different from each other, or from making the orientations (central angles) L2 of the grooves 22 different from each other. do not have.

Here, the ridges arranged portions 20, 20 adjacent to each other in the width direction are set such that the azimuths in which the ridges 21 are set are shifted in the circumferential direction. As shown in FIGS. 4 and 6, the azimuth (central angle) L2 at which the grooves 22 are set in one protrusion arrangement portion 20 is the same as the protrusion portion 21 in the protrusion arrangement portion 20 adjacent in the width direction. corresponds to the azimuth (central angle) L1 of . Further, the orientation (central angle) L1 at which the ridge portion 21 is set in one ridge-arranged portion 20 corresponds to the azimuth (central angle) L2 of the groove portion 22 in the adjacent ridge-arranged portion 20. ing.

In the embodiment, one projected streak arrangement portion 20 is divided into six areas along the circumferential direction, and three projected streak portions 21 and three groove portions 22 are arranged alternately along the circumferential direction. . These are arranged in a total of eight rows at a pitch of 20 mm, for example, along the width direction. are alternately arranged every 20 mm, for example. In addition, when the roller bit 10 is projected from the end face side, the ridges and troughs are equally divided at every 60° with respect to the circumferential direction so that the outer edge of the roller bit 10 becomes a substantially perfect circle. In this way, the obstacle and one of the ridges (ridges 21) of the roller bit 10 are always in contact with each other. It can prevent chipping.

As described above, three problems are listed as conditions necessary for directly cutting an obstacle with the cutter head 1 of the excavator S. The roller bit 10 of the present invention satisfies the three conditions.

Regarding the first problem of subdividing obstacles, the roller bit 10 of the present invention minimizes the pitch in the width direction of the ridges 21 (mountain portions) so that the cutting trajectory of the tip 30 is substantially reduced. It is secured in the entire cross section (over the entire width). For this reason, compared to the conventional roller bit, a shape is realized in which large pieces are not left uncut in the trough portion. The reason why the pitch in the width direction of the ridges 21 (peak portions) could be narrowed as much as possible is that the peak portions and the valley portions are alternately arranged along the width direction. It can be said that the setting is significant. Since no large cut pieces are generated, the mud discharge line is not clogged, and the fluid for recycling the mud can be stably supplied. In addition, the cutter torque during cutting is stabilized, preventing the cutter from locking.

Next, regarding durability, which is the second issue, conventional fixed cutting bits are in a mode in which the chip embedded in the bit always cuts along one locus. As a result, the wear of the tip was conspicuous. In this regard, in general, in a roller bit, many carbide tips are embedded in the circumferential direction with respect to one tooth, and the load on the tips is distributed as the cutting bit itself rotates. is much less compared to the fixed cutting bit. Also in the roller bit 10 of the present invention, wear of the tip 30 can be suppressed.

Furthermore, regarding the third problem of low vibration and low noise, roller bits generally perform rotary crushing with chips as the bit itself rotates. For this reason, it can be said that vibration and noise are much lower compared to fixed cutting bits. The roller bit 10 of the present invention also achieves very low vibration and noise levels compared to fixed cutting bits.

In the above-described embodiment, grooves 22 formed longitudinally along the circumferential direction and recessed in a concave shape are formed between the ridges 21, 21 adjacent along the circumferential direction. In the embodiment, as shown in FIGS. 4 and 6, the groove portion 22 has a bottom portion 22a formed of a flat surface at the center in the longitudinal direction, and both longitudinal ends gradually become shallower away from the ends of the bottom portion 22a. It is composed of an inclined portion 22b that is a flat surface and an arc surface 22c that serves as a connecting portion to the ridge portion 21. As shown in FIG. In addition, the shape of the bottom surface of the groove 22 and the depth of the groove 22 can be appropriately changed according to the situation of obstacles, construction conditions, and the like. For example, the shape of the bottom surface of the groove portion 22 may be a cylindrical surface portion extending around the axis. Moreover, the depth of the groove 22 may be deeper than the depth of the groove 22 of this embodiment, or may be shallower. Further, without providing the groove 22 between the circumferentially adjacent ridges 21 , 21 , the cylindrical surface portion in the axial direction that is not recessed, or the height relatively lower than the ridges 21 . It is good also as a mountain part. However, it is not necessary to provide the tip 30 on the cylindrical surface portion or peak portion.

In the above-described embodiment, as shown in FIG. 4, the azimuth (central angle) L1 in which the ridge portion 21 in a certain ridge arrangement portion 20 is set is adjacent in the width direction. is positioned within the azimuth (central angle) between the protrusions 21 in the protrusion arrangement portion 20 of . That is, the azimuths (central angles) in which the protrusions 21 are set do not overlap between the adjacent protrusions 20 , 20 . Similarly, the azimuths (central angles) in which the grooves 22 are installed do not overlap between the adjacent protrusions 20 , 20 . By modifying this example, for example, a part of the azimuth (central angle) L1 in which the ridge portion 21 is set in one ridge arrangement portion 20 is the other ridge arrangement portion adjacent in the width direction. You may set so that it may overlap with the direction (central angle) of the protrusion part 21 in 20. FIG.

In the above-described embodiment, the direction of the protrusion arrangement portion 20 is arranged along the cross section perpendicular to the axis of the roller bit 10. You may arrange|position along the direction in which it inclines. Further, the form of the support shaft 13 is not limited to this embodiment, and any form of support shaft 13 capable of supporting the roller bit 10 so as to be rotatable about its axis with respect to the cutter head 1 can be employed.

1 cutter head 10 roller type cutting bit (roller bit)
11 Roller bit for central portion 12 Roller bit for end portion 13 Supporting shaft 20 Projection arrangement portion 21 Projection portion 22 Groove portion 30 Carbide chip (chip)
40 fixed cutting bit

Claims (2)

In the roller type cutting bit (10) rotatably attached to the cutter head (1) on the front of the excavator,
A ridge arrangement portion (20) having a ridge portion (21) intermittently set along the circumferential direction and a plurality of tips (30) provided along the ridgeline of the ridge portion (21). , comprising a plurality of rows along the width direction intersecting the circumferential direction,
The roller type cutting bit, wherein the protrusions (20, 20) adjacent to each other in the width direction are set such that the orientations of the protrusions (21) are shifted in the circumferential direction. 2. The roller type cutting bit according to claim 1, wherein a groove portion (22) formed longitudinally along the circumferential direction and recessed in a concave shape is provided between the circumferentially adjacent ridge portions (21, 21). .

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