JP6837047B2 - Excavation agitator and ground improvement machine equipped with excavation agitator - Google Patents

Description

The present invention relates to an excavation agitator used to form a column-shaped structure in the ground in a ground improvement method, a continuous water blocking wall method, etc., and a ground improvement machine provided with an excavation agitation device.

Conventionally, an excavation agitator of a ground improvement machine used for forming a columnar structure (that is, performing ground improvement) has been known (see Patent Document 1). This excavation agitator is located at the lower end of the auger rod of the ground improvement machine.

Specifically, the drilling stirring device, as shown in FIG. 11, a plurality of rotating blades (stirring blade) 501 that rotates about axis C ₅ around with the rotation of the auger rod, a plurality of central axis C ₅ direction It is provided with a plurality of co-rotation prevention blades 502 which are arranged adjacent to the rotor 501 of the above and are rotatably arranged with respect to the auger rod and prevent co-rotation of the excavated soil with the rotor 501. ..

Each rotor blade 501 is spaced straight extending and intervals in the rotational direction in the direction perpendicular to the center axis C _5. Each co-rotation prevention blades 502 are also spaced straight extending and intervals in the rotational direction in the direction perpendicular to the center axis C _5. The central axis C ₅ direction of spacing of the respective rotor blade 501 and the co-rotation preventing wing 502 (particularly, overlapping when viewed from the central axis C ₅ direction and the rotary blades 501 and the co-rotation preventing wing 502 to rotate relative to each other the central axis C ₅ direction spacing) alpha when the, respectively the same.

Drilling stirring device 500, such as described above, when the soil improvement (i.e., during the formation of the by drilling ground cylindrical Construction body), a plurality of rotor blades in the rotation around the central axis C ₅ in the ground The ground is excavated in a columnar shape or the excavated soil and cement milk are agitated by the relative rotation of the 501 and the plurality of co-rotation prevention blades 502.

JP-A-2018-111979

During the ground improvement using the excavation agitator 500 as described above, if lumps of clay, stone, glass, etc. with _{an interval of more than α 5 are mixed in the excavated soil inside the excavated columnar improved body, the rotor blades} When the 501 and the co-rotation prevention blade 502 rotate relative to each other, the mass may be caught between the rotary blade 501 and the co-rotation prevention blade 502. In this case, the excavation stirring device 500 must be pulled up from the improved body to remove the lump, which lowers the work efficiency. Further, when biting occurs between the rotary blade 501 and the co-rotation prevention wing 502, the co-rotation prevention wing 502 rotates together with the rotary wing 501, and the original function of the co-rotation prevention wing 502 is hindered. As a result, a co-rotation phenomenon occurs and mixing and stirring with cohesive soil cannot be performed well.

Therefore, an object of the present invention is to provide an excavation agitator in which it is difficult for a mass mixed in excavated soil to be caught between a rotary blade and a co-rotation prevention blade, and a ground improvement machine equipped with the excavation agitation device. To do.

The excavation agitator of the present invention
An excavation agitator that is placed at the end of an auger rod of a ground improvement machine equipped with an auger rod that is long and can rotate around the central axis to excavate the ground.
A plurality of rotor blades that rotate around the central axis with the rotation of the auger rod, each of which extends along a direction orthogonal to the central axis and is arranged at intervals in the rotation direction. With wings
With a plurality of co-rotation prevention blades that are rotatably arranged with respect to the auger rod at a position adjacent to the plurality of rotor blades in the central axis direction and prevent co-rotation of the excavated soil with the plurality of rotor blades. A plurality of co-rotation prevention blades, each of which extends along a direction orthogonal to the central axis and is arranged at intervals in the rotation direction, are provided.
The positions of the end edges on the co-rotation prevention blade side in the central axis direction of each rotor are the same.
The distance between the first co-rotation prevention blade, which is a part of the co-rotation prevention blades of the plurality of co-rotation prevention blades, and each of the rotary blades in the central axis direction is the distance between the co-rotation prevention blades. It is larger than the distance between the second co-rotation prevention blade, which is the remaining co-rotation prevention blade, and each rotor blade in the central axial direction.

According to this configuration, the rotor blades rotate with the rotation of the auger rod in a state where the rotation of the rotor blades is suppressed during excavation of the ground, so that the rotor blades and the rotor blades rotate relative to each other. When this is done, the distance between the first co-rotation prevention blade and each rotor (first spacing) is larger than the distance between the second co-rotation prevention blade and each rotor (second spacing), so co-rotation Compared to the excavation agitator where the distance between the prevention blade and the rotor blade is all the first distance, the mass mixed in the excavated soil (for example, a mass such as clay or stone, so-called glass) is co-rotated with the rotor blade and the rotor blade. It becomes difficult to bite between.

If the distance between the rotary blade and the co-rotation prevention blade is too wide, the function of unraveling the lumps (cohesive soil lumps, etc.) mixed in the excavated soil deteriorates.
From the edge of one blade of the rotor blade and the co-rotation prevention blade on the other blade side, the other blade side does not come into contact with the other blade when the rotor blade and the co-rotation prevention blade rotate relative to each other. Equipped with an extension plate that extends to
It is preferable that the extension plate is elastically deformable so that the portion on the tip end side in the extension direction is displaced in the direction opposite to the rotation direction of the one blade with respect to the other blade.

By providing the extension plate in this way, the distance between the blades (rotor blades, co-rotation prevention blades) that rotate relative to each other in the central axis direction is reduced or partially reduced, so that when the excavated soil is agitated, etc. The excavated soil and the like can be crushed more finely. Moreover, since the extension plate is elastically deformable, even if the other wing and the extension plate are about to bite the mass, the extension plate is elastically deformed (see FIG. 6). Can be prevented.

Further, the ground improvement machine of the present invention is
An auger rod that is long and can rotate around the central axis,
An excavation agitator located at the end of the auger rod to excavate the ground is provided.
The excavation agitator
A plurality of rotor blades that rotate around the central axis with the rotation of the auger rod, each of which extends along a direction orthogonal to the central axis and is arranged at intervals in the rotation direction. With wings
With a plurality of co-rotation prevention blades that are rotatably arranged with respect to the auger rod at a position adjacent to the plurality of rotor blades in the central axis direction and prevent co-rotation of the excavated soil with the plurality of rotor blades. Each has a plurality of co-rotation prevention blades that extend along a direction orthogonal to the central axis and are arranged at intervals in the rotation direction.
The positions of the end edges on the co-rotation prevention blade side in the central axis direction of each rotor are the same.
The distance between the first co-rotation prevention blade, which is a part of the co-rotation prevention blades of the plurality of co-rotation prevention blades, and each of the rotary blades in the central axis direction is the distance between the co-rotation prevention blades. It is larger than the distance between the second co-rotation prevention blade, which is the remaining co-rotation prevention blade, and each rotor blade in the central axial direction.

According to this configuration, the rotor blades rotate with the rotation of the auger rod in a state where the rotation of the rotor blades is suppressed during excavation of the ground, so that the rotor blades and the rotor blades rotate relative to each other. When this is done, the distance between the first co-rotation prevention blade and each rotor (first spacing) is larger than the distance between the second co-rotation prevention blade and each rotor (second spacing), so co-rotation Compared to the excavation agitator where the distance between the prevention blade and the rotor blade is all the first distance, the mass mixed in the excavated soil (for example, a mass such as clay or stone, so-called glass) is co-rotated with the rotor blade and the rotor blade. It becomes difficult to bite between.

Based on the above, according to the present invention, there is provided an excavation agitator that makes it difficult for a mass mixed in excavated soil to be caught between a rotary blade and a co-rotation prevention blade, and a ground improvement machine equipped with the excavation agitation device. Can be done.

FIG. 1 is a diagram showing a usage state of the ground improvement machine according to the present embodiment. FIG. 2 is a front view of the excavation agitation device included in the ground improvement machine. FIG. 3 is a side view of the excavation agitator. FIG. 4 is a cross-sectional view of the boss portion and the co-rotation prevention blade of the excavation stirring device at the IV-IV position of FIG. 5 (a) and 5 (b) are schematic views for explaining the excavation state of the ground by the excavation agitator. FIG. 6 is a diagram showing a state in which the extension plate is curved. FIG. 7A is a front view of the excavation agitation device according to the other embodiment, and FIG. 7B is a side view of the excavation agitation device according to the other embodiment. 8A is a front view of the excavation agitator according to the other embodiment, and FIG. 8B is a side view of the excavation agitator according to the other embodiment. FIG. 9 is a front view of the excavation agitation device according to another embodiment. FIG. 10 is a front view of the excavation agitation device according to another embodiment. FIG. 11 is a front view of a conventional excavation agitator.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

As shown in FIG. 1, the ground improvement machine provided with the excavation agitation device according to the present embodiment includes a base machine 2 having a leader mast 21 erected in a substantially vertical direction and an excavation agitation device 3 for excavating the ground. It includes a ground improvement drive unit 4 that has and is arranged on the leader mast 21.

A transport hose 92 extending from a storage tank 91 in which cement milk is stored is connected to the ground improvement machine 1, and cement milk is supplied from the storage tank 91 by driving a pump 93 arranged in the storage tank 91 or the transport hose 92. Will be done.

The ground improvement drive unit 4 is arranged in the leader mast 21 so as to be able to move up and down with respect to the leader mast 21, and a columnar hole extending in the vertical direction is excavated in the ground (underground) and the excavated columnar hole is excavated. Inside, the excavated soil (excavated soil) and the cement milk supplied from the storage tank 91 are agitated.

Specifically, the ground improvement drive unit 4 rotates a long auger rod 41 extending in a substantially vertical direction, an excavation agitator 3 detachably attached to the lower end (tip) of the auger rod 41, and an auger rod 41. It has a rotation drive device 42 and.

Auger rod 41 is supported by the central axis C ₁ has, and vertically movable leader mast 21 rotatable central axis C ₁ around a substantially vertically extending. The auger rod 41 has an internal flow path 411 that extends in the elongated direction to the lower end and allows the cement milk supplied from the storage tank 91 to flow.

Rotary drive device 42, driven to rotate the central axis C ₁ around the auger rod 41. The rotary drive device 42 of the present embodiment is connected to the upper end of the auger rod 41.

Drilling stirrer 3, as shown in FIGS. 2 and 3, a plurality of rotary blades 32 rotating about axis C ₂ around with the rotation of the auger rod 41, the rotary blade 32 in the central axis C ₂ direction It has a plurality of co-rotation prevention blades 35 that are rotatably arranged with respect to the auger rod 41 at adjacent positions and that prevent co-rotation of the excavated soil with the rotor blade 32. The plurality of rotary blades 32 and the plurality of co-rotation prevention blades 35 can rotate relative to _{each other around the central axis C2.} The excavation stirring device 3 also has an extension plate 33 extending from the rotary blade 32 or the co-rotation prevention blade 35. In the excavation stirring device 3 of the present embodiment, the extension plate 33 extends from the rotary blade 32.

Specifically, the drilling stirrer 3, the shaft portion connected to the lower end of the auger rod 41 the central axis C ₂ has and the central axis C ₂ in a state of being aligned with the center axis C ₁ of the auger rod 41 31, a plurality of rotary blades 32 extending from the shaft portion 31 in _{a direction orthogonal to the central axis C 2} , an extension plate 33 extending from the rotary blade 32 toward the co-rotation prevention blade 35, and a boss surrounding the shaft portion 31. A portion 34, a plurality of co-rotation prevention blades 35 extending from the boss portion 34 in _{a direction orthogonal to the central axis C 2,} and a tip portion (end portion (base end portion) 31a connected to the auger rod 41) of the shaft portion 31. It has a tip bit portion 36, which is arranged at an end portion) 31b on the opposite side.

In the soil improvement machine 1 of this embodiment, since the shaft portion 31 is connected to the lower end of the auger rod 41 as the central axis C ₂ of the center axis C ₁ and the shaft portion 31 of the auger rod 41 coincide, Hereinafter, the central axes C ₁ and C ₂ are simply referred to as "central axes C".

The shaft portion 31 extends in the central axis C direction. Specifically, the shaft portion 31 is provided at the base end portion 31a and is fitted into the lower end of the auger rod 41 to connect the excavation agitator 3 and the auger rod 41 to the joint portion 311 and the inside of the auger rod 41. It has an internal flow path 312 communicating with the flow path 411 and a discharge port 313 provided at the tip portion 31b and capable of discharging cement milk from the internal flow path 312 to the outside (outside of the excavation agitator 3). Further, the shaft portion 31 has a pair of collar portions 314 arranged at intervals in the central axis C direction at an intermediate position in the central axis C direction.

The plurality of rotary blades 32 extend from the shaft portion 31 along the direction orthogonal to the central axis C and are arranged at intervals in the rotational direction of the excavation stirring device 3. The excavation agitation device 3 of the present embodiment has a plurality of rotary blade sets 32A, with a plurality of rotary blades 32 arranged at the same position in the central axis C direction at intervals in the circumferential direction as a rotary blade set 32A. .. The plurality of rotary blade sets 32A are arranged at intervals in the central axis C direction.

_{In the excavation stirring device 3 of the present embodiment, the first set 32A 1} which is a set of rotary blades arranged at the tip portion 31b of the shaft portion 31 of the plurality of sets 32A of the rotary blades is composed of the excavation blades 321. _{The second set 32A 2} , which is the remaining set of rotors out of the set 32A of the plurality of rotors, is composed of the stirring blades 322.

The first set 32A ₁ of the present embodiment is composed of two excavation blades 321. The two excavation blades 321 extend in opposite directions from the shaft portion 31. That is, the angle formed by one excavation blade 321 and the other excavation blade 321 when viewed from the central axis C direction is 180 °. _{Further, each of the two second} sets 32A 2 is composed of two stirring blades 322, and the two stirring blades 322 extend from the shaft portion 31 in opposite directions. That is, the angle formed by one stirring blade 322 and the other stirring blade 322 when viewed from the central axis C direction is 180 °. Furthermore, one of the second set 32A _{direction 2} two stirring blades 322 constituting the extend respectively, and the direction in which the two stirring blades 322 extend respectively constituting the other of the second set 32A _2, the center axis C Seen from the direction, it is off by 90 °. Further, in the excavation stirring device 3 of the present embodiment _{, each of the two stirring blades 322 constituting the second set 32A 2} on one side (lower side in FIG. 3) in the central axis C direction is from the central axis C direction. As seen, each of the two stirring blades 322 extending in the direction displaced by 90 ° in the rotation direction from the excavation blade 321 and _{forming the second set 32A 2 on the other side (upper side in FIG. 2) in the central axis C direction is the center.} It extends in the same direction as the excavation blade 321 when viewed from the axis C direction. The number of blades (excavation blades 321 and stirring blades 322) constituting the sets 32A ₁ and 32A _{2 of each rotary blade is not limited to two, and may be three or more.}

Further, in the excavation stirring device 3 of the present embodiment, one first set 32A _{1 is arranged on the tip end 31b side of the boss portion 34, and the second set 32A 2} is arranged on the base end portion 31a side of the boss portion 34. Two are arranged. The first set 32A ₁ is arranged at a position adjacent to the boss portion 34 (plural co-rotation prevention blades 35) in the central axis C direction, and is on the tip end 31b side (center _{) of the two second sets 32A 2. The second set 32A 2} (on one side in the axis C direction) is also arranged at a position adjacent to the boss portion 34 (plural co-rotation prevention blades 35) in the central axis C direction.

Each of the plurality of excavation blades 321 has a plate-shaped excavation blade main body 3211 extending from the shaft portion 31 in a direction orthogonal to the central axis C, and a ridge reinforcing portion 3212 extending from the shaft portion 31 along the excavation blade main body 3211. , A plurality of excavation bits 3213 protruding from one end edge 3211a in the central axis C direction in the excavation blade main body 3211.

The excavation wing main body 3211 has a substantially rectangular plate shape that is long in a direction orthogonal to the central axis C, and is a portion on the side in the direction of rotation (hereinafter, referred to as "first rotation direction") during excavation of the ground. It is inclined with respect to the central axis C so as to be located on one side in the central axis C direction.

The other end edge 3211b of each of the drilling blades 321 of the plurality of drilling blades 321 in the direction of the central axis C extends straight in the direction orthogonal to the central axis C. The positions of the edge 3211b of each excavation blade main body 3211 in the central axis C direction are the same.

The reinforcing portion 3212 protrudes from the back surface (the surface opposite to the first rotation direction) 3211r of the excavation blade main body 3211 and faces the tip of the excavation blade main body 3211 (the end opposite to the shaft portion 31) from the shaft portion 31. Is extending.

The plurality of excavation bits 3213 are arranged at intervals along the edge 3211a of the excavation blade main body 3211. Each of the plurality of excavation bits 3213 is inclined with respect to the inclined surface (surface) 3211f of the excavation blade main body 3211 and protrudes from the end edge 3211a so as to be directed in the first rotation direction.

Each of the plurality of stirring blades 322 includes a plate-shaped stirring blade main body 3221 extending from the shaft portion 31 in a direction orthogonal to the central axis C, and a ridge reinforcing portion 3222 extending from the shaft portion 31 along the stirring blade main body 3221. , Have.

The stirring blade main body 3221 has a substantially rectangular plate shape that is long in the direction orthogonal to the central axis C, and the portion on the first rotation direction side is located on one side in the central axis C direction with respect to the central axis C. Is tilted.

The reinforcing portion 3222 protrudes from the back surface (the surface opposite to the first rotation direction) 3221r of the stirring blade main body 3221 and faces the tip of the stirring blade main body 3221 (the end opposite to the shaft portion 31) from the shaft portion 31. Is extending.

The extension plate 33 is formed from the end edge 3211b of the excavation blade 321 (excavation blade main body 3211) on the other side (co-rotation prevention blade 35 side) in the central axis C direction to the excavation blade 321 (rotor blade 32) and the co-rotation prevention blade. When the 35 and the relative rotation around the central axis C, they extend to the other side in the central axis C direction within a range that does not come into contact with the co-rotation prevention blade 35. In this extension plate 33, when the excavation blade 321 rotates (rotates in the first rotation direction), the portion on the tip side (co-rotation prevention blade 35 side) in the extension direction is the rotation direction with respect to the co-rotation prevention blade 35. It can be elastically deformed so as to be displaced in the opposite side (the side opposite to the first rotation direction (second rotation direction)) (see FIG. 6).

The extension plate 33 of the present embodiment is a rectangular so-called spring plate, and extends from the end edge 3211b of the excavation blade body 3211 so as to be substantially parallel to the surface 3211f of the excavation blade body 3211 and toward the second rotation direction side. ing. The extension plate 33 is a plate member made of, for example, stainless steel, spring steel, or the like, and has a thickness of 2 mm to 4 mm. The thickness and receiving area of the extension plate 33 are set based on the reaction force received from the mass (soil mass, glass, etc.) contained in the excavated soil when the excavation blade 321 rotates. The extension plate 33 may be attached to the excavation blade main body 3211 in a state where a plurality of the extension plates 33 are overlapped with each other.

Further, a plurality of (two in the example shown in FIG. 2) extension plates 33 are arranged on each excavation blade 321. The positions of the plurality of extension plates 33 (distance from the shaft portion 31 in the direction orthogonal to the central axis C) in each excavation blade 321 are different from each other. Specifically, the position of each extension plate 33 is one of the excavation blades (the excavation blade on the right side in FIG. 2) when the two excavation blades 321 rotate around the central axis C at the same position in the central axis C direction. Each area through which the extension plate 33 arranged in 321 passes and each area through which the extension plate 33 arranged in the other excavation blade (excavation blade on the left side of FIG. 2) 321 passes do not overlap. Each is set.

The boss portion 34 surrounds the circumference of the shaft portion 31 between the excavation blade 321 in the central axis C direction and the stirring blade ( _{the stirring blade forming the second set 32A 2 on one side in the central axis C direction) 322.} Moreover, it is a tubular member in which the co-rotation prevention blade 35 is arranged. The boss portion 34 of the present embodiment surrounds the shaft portion 31 between the pair of collar portions 314. The boss portion 34 is rotatable around the shaft portion 31. Specifically, as shown in FIG. 4, the boss portion 34 is arranged on the radial inner side (inner peripheral surface side) of the metal tubular outer shell portion 341 and the outer shell portion 341, and the shaft portion 31. It has a tubular sliding contact portion 342 that comes into contact with.

The sliding contact portion 342 comes into sliding contact with the outer peripheral surface of the shaft portion 31 when the shaft portion 31 rotates around the central axis C with the rotation of the auger rod 41. The sliding contact portion 342 of the present embodiment is formed of a synthetic resin, more specifically, MC nylon (registered trademark). By using the resin in this way, when the boss portion 34 rotates around the shaft portion 31, that is, when the shaft portion 31 and the boss portion 34 rotate relative to each other, the generation of metal powder due to wear can be suppressed.

Each of the plurality of co-rotation prevention blades 35 extends from the boss portion 34 (specifically, the outer peripheral surface of the outer shell portion 341) along the direction orthogonal to the central axis C and is arranged at intervals in the rotation direction. Two co-rotation prevention wings 35 (first co-rotation prevention wing 35A, second co-rotation prevention wing 35B) are arranged on the boss portion 34 of the present embodiment, and these two co-rotation prevention wings 35 are They extend from the boss portion 34 in opposite directions. That is, the angle formed by the first co-rotation prevention blade 35A and the second co-rotation prevention blade 35B when viewed from the central axis C direction is 180 °. The number of co-rotation prevention blades 35 is not limited to two, and may be three or more.

As described above, in the excavation stirring device 3 of the present embodiment, since each of the plurality of co-rotation prevention blades 35 extends from the boss portion 34 and the boss portion 34 is rotatable with respect to the shaft portion 31, each of them The rotation prevention blade 35 is rotatable with respect to the shaft portion 31.

The first co-rotation prevention blade 35A is a plate-shaped portion extending from the boss portion 34 in a direction orthogonal to the central axis C. Specifically, the first co-rotation prevention blade 35A is a band that is long and straight in the direction orthogonal to the central axis C direction as well as along the surface including the central axis C direction and the direction orthogonal to the central axis C. It is plate-shaped. The dimensions of the first co-rotation prevention blade 35A in the direction orthogonal to the central axis C are the dimensions in the direction orthogonal to the central axis C in the excavation blade 321 and the dimensions in the direction orthogonal to the central axis C in the stirring blade 322, respectively. Greater.

The second co-rotation prevention wing 35B is located on the boss portion 34 from a position opposite to the first co-rotation prevention wing 35A with the central axis C in between, in the direction opposite to the extending direction of the first co-rotation prevention wing 35A. It is a plate-shaped part that extends. Specifically, the second co-rotation prevention blade 35B has a strip-like shape that extends along a surface including the direction of the central axis C and the direction orthogonal to the central axis C, and is long and bends in the middle. Specifically, the second co-rotation prevention blade 35B is inclined with respect to the direction orthogonal to the central axis C so as to be located on the excavation blade 321 side (one side in the central axis C direction) as the distance from the boss portion 34 increases. It has an inclined portion 351B extending in a straight direction, and a parallel portion 352B extending straight from the tip end of the inclined portion 351B (the end portion opposite to the shaft portion 31) in a direction orthogonal to the central axis C. This parallel portion 352B is a portion that becomes parallel to the excavation blade 321 when the excavation blade 321 and the second co-rotation prevention blade 35B overlap each other when viewed from the central axis C direction due to relative rotation (FIG. 2). Further, the dimensions of the second co-rotation prevention blade 35B in the direction orthogonal to the central axis C are the same as those of the first co-rotation prevention blade 35A, that is, the dimensions of the excavation blade 321 in the direction orthogonal to the central axis C, and It is larger than each of the dimensions of the stirring blade 322 in the direction orthogonal to the central axis C.

As described above, in the excavation stirring device 3, the first co-rotation prevention blade 35A, which is a part of the co-rotation prevention blades 35 among the plurality of co-rotation prevention blades 35, and each excavation blade 321 (rotary blade 32). The distance in the central axis C direction is the central axis C direction between the second co-rotation prevention blade 35B, which is the remaining co-rotation prevention blade of the plurality of co-rotation prevention blades 35, and each excavation blade 321 (rotary blade 32). Greater than the interval. Specifically, in a state where the co-rotation prevention blade 35 and the excavation blade 321 overlap each other when viewed from the central axis C direction due to relative rotation, the distance between the first co-rotation prevention blade 35A and each excavation blade 321 in the central axis C direction. (First distance α _{1 ) is larger than the distance (second distance α 2} ) between the parallel portion 352B of the second co-rotation prevention blade 35B and each excavation blade 321 in the central axis C direction (see FIG. 2).

Further, in the excavation stirring device 3, the central axis of the second co-rotation prevention blade 35B (parallel portion 352B) and each stirring blade 322 (rotary blade 32) constituting _{the second set 32A 2 on the tip portion 31b side.} The distance in the C direction (third distance α ₃ ) is the central axis between the first co-rotation prevention blade 35A and each stirring blade 322 (rotary blade 32) constituting _{the second set 32A 2 on the tip end 31b side.} It is larger than the interval in the C direction (fourth interval α _4).

Further, in the excavation stirring device 3 of the present embodiment, the first interval α ₁ and the third interval α ₃ are the same or substantially the same size, and the second interval α ₂ and the fourth interval α ₄ are the same or substantially the same. It is the same size.

The first and second intervals α ₁ and α ₂ are the end edge 3211b on the side of the co-rotation prevention blade 35 in the excavation blade 321 and the end edge on the excavation blade 321 side in the co-rotation prevention blade 35 (second co-rotation). In the prevention blade 35B, it is the distance in the direction of the central axis C from the edge of the parallel portion 352B on the excavation blade 321 side). Further, the third and fourth intervals α ₃ and α ₄ are the ends on the stirring blade 322 side of the co-rotation prevention blade 35 (in the second co-rotation prevention blade 35B, the ends on the stirring blade 322 side in the parallel portion 352B. The distance between the edge) and the edge of the stirring blade 322 on the side of the co-rotation prevention blade 35 in the central axis C direction.

_{In the excavation stirring device 3 of the present embodiment, the distance (first distance) α 1} between the excavation blade 321 and the first co-rotation prevention blade 35A in the central axis C direction is 160 mm to 190 mm, and the extension plate 33. The distance between the first co-rotation prevention blade 35A and the first co-rotation prevention blade 35A in the central axis C direction is 118 mm. _{Further, the distance (second distance) α 2} between the excavation blade 321 and the second co-rotation prevention blade 35B (parallel portion 352B) in the central axis C direction is 100 mm to 130 mm, and the extension plate 33 and the second The distance from the co-rotation prevention blade 35B (parallel portion 352B) in the central axis C direction is 46 mm. _{Further, the distance (fourth distance) α 4} between the first co-rotation prevention blade 35A and the stirring blade 322 in the central axis C direction is 100 mm to 130 mm, and the second co-rotation prevention blade 35B and the stirring blade 322 The distance (third distance) α _{3 in} the direction of the central axis C is 190 mm to 210 mm.

The tip bit portion 36 has a plurality of (two in the example of the present embodiment) excavation bits 361, and is arranged at the tip portion 31b of the shaft portion 31.

The ground improvement machine 1 configured as described above performs ground improvement as follows, that is, forms a columnar structure in the ground.

First, the ground improvement drive unit 4 rotates the auger rod 41 in the first rotation direction, so that the excavation stirring device 3 (excavation blade 321) rotates around the central axis C. In this state, the ground improvement drive unit 4 descends along the leader mast 21, and the excavation agitator 3 excavates the ground in a columnar shape.

At this time, since the tip of the co-rotation prevention blade 35 projects to the outside (outside in the direction orthogonal to the central axis C) from the tips of the excavation blade 321 and the stirring blade 322, the tip of the excavation blade 321 extends to the peripheral wall of the excavated hole. The excavation agitator 3 (ground improvement drive unit 4) descends while excavating the ground with the co-rotation prevention blade 35 biting into the tip portion thereof. As a result, the excavation blade 321 and the stirring blade 322 rotate around the central axis C while the rotation of the co-rotation prevention blade 35 (rotation around the central axis C) is suppressed, that is, the co-rotation prevention blade 35 and the co-rotation prevention blade 35. The excavation blade 321 and the stirring blade 322 rotate relative to each other.

When the excavation agitation device 3 reaches a predetermined depth, the descent of the ground improvement drive unit 4 stops. Subsequently, the ground improvement drive unit 4 rotates the auger rod 41 in the second rotation direction (rotates in the reverse direction) and starts to rise. At this time, cement milk is supplied from the storage tank 91 to the ground improvement machine 1 through the transport hose 92, and the supplied cement milk passes through the auger rod 41 and the internal flow paths 411 and 312 of the excavation agitation device 3 to excavate and agitate. It is discharged from the discharge port 313 at the tip (lower end) of the device 3 (shaft portion 31) into a hole (a columnar hole formed by excavation of the excavation stirring device 3).

By discharging the cement milk and rotating the excavation stirring device 3 in the second rotation direction, the excavated soil and the cement milk are agitated inside the hole. Then, while the ground improvement drive unit 4 agitates the cement milk and the excavated soil, it moves up or down in the excavated hole in combination, and then until the excavation agitator 3 appears on the ground. , Ascend along the leader mast 21. After that, the excavated soil and the agitated cement milk solidify inside the excavated columnar hole to form a columnar structure in the ground.

In the above-mentioned ground improvement machine 1, in the excavation stirring device 3, a part of the co-rotation prevention blades 35 (first co-rotation prevention blade 35A) and each excavation blade 321 (rotary blade 32) of the plurality of co-rotation prevention blades 35 are used. ) With the distance (first distance) α _{1 in} the central axis C direction with the remaining co-rotation prevention blades (second co-rotation prevention blade 35B (parallel portion 352B)) among the plurality of co-rotation prevention blades 35. _{The distance (second distance) α 2 in} the central axis C direction from each drilling blade 321 (rotary blade 32) is larger. Therefore, when excavating the ground or stirring the excavated soil with cement milk, the excavation blade 321 (rotary blade 32) is rotated along with the rotation of the auger rod 41 in a state where the rotation of the co-rotation prevention blade 35 is suppressed. When the co-rotation prevention wing 35 and the excavation wing 321 (rotary wing 32) rotate relative to each other due to rotation, the distance between the co-rotation prevention wing and the excavation wing (rotary wing) is all the first distance α _1. Compared to the agitator, it becomes difficult for a lump mixed with excavated soil or the like (for example, a lump of clay or stone, so-called glass, etc.) to be caught between the co-rotation prevention blade 35 and the excavation blade 321 (rotary blade 32). That is, if the mass mixed in the excavated soil is _{smaller than the first interval α 1} , at least the biting of the mass between the first co-rotation prevention blade 35A and the excavation blade 321 (rotor blade 32) is prevented. Is done.

Further, in the excavation stirring device 3, the central axis of the second co-rotation prevention blade 35B (parallel portion 352B) and each stirring blade 322 (rotary blade 32) constituting _{the second set 32A 2 on the tip portion 31b side.} The distance (third distance) α _{3 in} the C direction is the central axis between the first co-rotation prevention blade 35A and each stirring blade 322 (rotary blade 32) constituting _{the second set 32A 2 on the tip end 31b side.} C direction between larger (fourth distance) alpha _4. Therefore, when excavating the ground or stirring the excavated soil and cement milk, the stirring blade 322 (rotary blade 32) is rotated as the auger rod 41 rotates while the rotation of the co-rotation prevention blade 35 is suppressed. when the co-rotation preventing blades 35 by rotating which the stirring blades 322 (rotor blades 32) are relatively rotated, a ₄ interval is every fourth distance α between the co-rotation preventing wing and stirring blade (rotating blade) drilling Compared with the stirring device, it becomes difficult for the mass mixed in the excavated soil (for example, a mass of clay, stone, so-called glass, etc.) to be caught between the co-rotation prevention blade 35 and the stirring blade 322 (rotary blade 32).

For example, as shown in FIG. 5, a mass (for example, a mass of clay, stone, so-called glass, etc.) m that has passed through _{the first interval α 1 descends the excavation stirring device 3 (ground improvement drive unit 4) or excavates. When the excavated soil is moved to the position of the third interval α 3} due to the movement of the excavated soil due to the rotation of the blade 321 and the stirring blade 322 or the like, the mass m is not bitten because it passes through the third interval α _3. As described above, in the ground improvement machine 1 (excavation stirring device 3) of the present embodiment, the distances α ₁ and α ₃ between some of the co-rotation prevention blades 35 and the rotary blades 32 (excavation blades 321 and stirring blades 322) are set. By making the distance between the other co-rotation prevention blade 35 and the rotary blade 32 (excavation blade 321, stirring blade 322) _{wider than α 2} and α ₄ , the co-rotation prevention blade 35 and the rotary blade 32 (excavation blade 321, stirring blade 32) are made wider. Compared with the excavation agitator having the same interval with the blade 322) (for example, all the intervals α ₂ and α ₄ ), the possibility of the lump m mixed in the excavated soil being bitten is suppressed.

Further, in the ground improvement machine 1 of the present embodiment, in the excavation stirring device 3, the extension plate 33 extends from the end edge 3211b of the excavation blade 321 on the co-rotation prevention blade 35 side, and the extension plate 33 extends in the extension direction. The portion on the tip end side of the excavation blade 321 can be elastically deformed so as to be displaced in the direction opposite to the rotation direction with respect to the co-rotation prevention blade 35. By providing the extension plate 33 in this way, the distance between the blades (excavation blade 321 and the co-rotation prevention blade 35) that rotate relative to each other in the central axis C direction becomes smaller or partially smaller, so that the excavated soil becomes more compact. It is crushed into small pieces. Moreover, since the extension plate 33 can be elastically deformed, even if the co-rotation prevention blade 35 and the extension plate 33 are about to bite the lump m, the extension plate 33 is elastically deformed (FIG. 6). (See) The biting can be prevented.

The excavation agitation device of the present invention and the ground improvement machine provided with the excavation agitation device are not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the gist of the present invention. is there. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. In addition, some of the configurations of certain embodiments can be deleted.

In the excavation agitation device 3 of the above embodiment, the first interval α ₁ is larger than the second interval α ₂ and the third interval α ₃ is larger than the fourth interval α _4, but the configuration is not limited to this.

For example, as shown in FIG. 7, the first interval α ₁ may be larger than the second interval α _{2 , and the intervals α 5} between the co-rotation prevention blade 35 and the stirring blade 322 may be the same. Further, as shown in FIG. 8, the co-rotation prevention blade 35 and the excavation blade 321 _{may have the same distance α 6} and the third distance α ₃ may be larger than the fourth distance α _4.

In the excavation stirring device 3 of the above embodiment, the second co-rotation prevention blade 35B has a strip-like shape that bends in the middle, but is not limited to this configuration. As shown in FIG. 9, each of the plurality of co-rotation prevention blades 35C may have a strip shape extending straight in a direction orthogonal to the central axis C. That is, at least a part of the plurality of co-rotation prevention blades 35C may extend from different positions in the central axis C direction on the boss portion 34.

Further, in the excavation stirring device 3 of the above embodiment, the co-rotation prevention blade 35 has a strip-like shape having a constant thickness, but is not limited to this configuration. The co-rotation prevention blade 35C has a tip portion 355 (specifically, a portion projecting radially outward from at least the tip of the excavation blade 321 and the tip of the stirring blade 322 in the direction orthogonal to the central axis C) on the base side. (Part on the shaft portion 31 side) It may be thinner than 356. For example, in the example shown in FIG. 9, the thickness of the tip portion 355 of the co-rotation prevention blade 35C is 2 mm to 4 mm, and the thickness of the other portion 356 is 45 mm. According to such a configuration, when excavating the ground, the tip portion 355 of the co-rotation prevention blade 35C is likely to bite into the peripheral wall of the hole (excavated hole).

In the excavation stirring device 3 of the above embodiment, the extension plate 33 extends from the excavation blade 321 but is not limited to this configuration. For example, as shown in FIG. 10, the extension plate 33 may extend from the co-rotation prevention blade 35. In this case, the extension plate 33 may extend from one end edge of the co-rotation prevention blade 35 in the central axis C direction (lower side in FIG. 10), and may extend from the edge of the co-rotation prevention blade 35 in the central axis C direction. It may extend from the edge on the other side (upper side in FIG. 10). Further, the extension plate 33 may extend from both end edges of the co-rotation prevention blade 35 in the central axis C direction. Further, the extension plate 33 may extend from the stirring blade 322. Further, the excavation agitation device 3 may be configured without the extension plate 33.

The excavation stirring device 3 of the above embodiment is detachably connected to the auger rod 41, but is not limited to this configuration. For example, the excavation agitation device 3 may be integrated with the auger rod 41.

1 ... Ground improvement machine, 2 ... Base machine, 21 ... Leader mast, 3 ... Excavation stirrer, 31 ... Shaft part, 31a ... Base end part, 31b ... Tip part, 311 ... Joint part, 312 ... Internal flow path, 313 ... Discharge port, 314 ... Collar, 32 ... Rotating wing, 32A ... Rotating wing set, 32A ₁ ... First set, 32A ₂ ... Second set, 321 ... Excavation wing (rotary wing), 3211 ... Excavation wing Main body, 3211a ... One end edge in the central axis direction, 3211b ... The other end edge in the central axis direction, 3211f ... Front surface, 3211r ... Back surface, 3212 ... Reinforcing part, 3213 ... Excavation bit, 322 ... Stirring blade (rotation) Wings), 3221 ... Stirring blade body, 3222 ... Reinforcing part, 33 ... Extension plate, 34 ... Boss part, 341 ... Outer shell part, 342 ... Sliding contact part, 35, 35C ... Co-rotation prevention blade, 35A ... First Co-rotation prevention blade, 35B ... Second co-rotation prevention blade, 351B ... Inclined part, 352B ... Parallel part, 355 ... Tip part, 36 ... Tip bit part, 361 ... Excavation bit, 4 ... Ground improvement drive part, 41 ... Auger rod, 411 ... Internal flow path, 42 ... Rotation drive, 91 ... Storage tank, 92 ... Transport hose, 93 ... Pump, 500 ... Excavation stirrer, 501 ... Rotating blade, 502 ... Co-rotation prevention blade, C, C ₁ , C ₂ , C ₅ ... Central axis, m ... Mass, α ₁ ... First interval, α ₂ ... Second interval, α ₃ ... Third interval, α ₄ ... Fourth interval, α ₅ , α ₆ ... interval

Claims (2)

An excavation agitator that is attached to the end of an auger rod of a ground improvement machine equipped with an auger rod that extends along the central axis and is rotatable around the central axis to excavate soil.
A plurality of rotor blades that rotate around the central axis with the rotation of the auger rod, each of which extends along a direction orthogonal to the central axis and is arranged at intervals in the rotation direction. With wings
A plurality of co-rotation prevention blades for preventing co-rotation of excavated soil with the plurality of rotor blades rotatably arranged with respect to the auger rod at a position adjacent to the plurality of rotor blades in the central axis direction. A plurality of co-rotation prevention blades, each of which extends along a direction orthogonal to the central axis and is arranged at intervals in the rotation direction, are provided.
The positions of the end edges on the co-rotation prevention blade side in the central axis direction of each rotor are the same.
The distance between the first co-rotation prevention blade, which is a part of the co-rotation prevention blades of the plurality of co-rotation prevention blades, and each of the rotary blades in the central axis direction is the distance between the co-rotation prevention blades. the second co-rotation preventing blade and the rather larger than distance between the central axis direction of each rotor blade is the remaining co-rotation prevention wings,
Each rotor has an extension plate that extends from the end edge on the co-rotation prevention blade side within a range that does not come into contact with the co-rotation prevention blade when relatively rotated.
Each extension plate can be elastically deformed so that the portion on the tip side in the extension direction is displaced in the direction opposite to the rotation direction of the rotary blade with respect to the co-rotation prevention blade.
The position of the extension plate in each rotor in the direction orthogonal to the central axis is arranged in one rotor when each rotor rotates around the central axis at the same position in the central axis direction. An excavation agitator in which a region through which the extended plate is passed is set so as not to overlap with a region through which the extended plate is arranged on another rotor. An auger rod that extends along the central axis and can rotate around the central axis,
An excavation agitator located at the end of the auger rod to excavate the soil.
The excavation agitator
A plurality of rotor blades that rotate around the central axis with the rotation of the auger rod, each of which extends along a direction orthogonal to the central axis and is arranged at intervals in the rotation direction. With wings
There it in a position adjacent to the plurality of rotor blades in the central axis direction of the plurality of preventing co-rotation of the plurality of rotor blades of the soil that is excavated by being rotatably arranged relative to the auger rod It has a plurality of co-rotation prevention blades, each of which extends along a direction orthogonal to the central axis and is arranged at intervals in the rotation direction.
The positions of the end edges on the co-rotation prevention blade side in the central axis direction of each rotor are the same.
The distance between the first co-rotation prevention blade, which is a part of the co-rotation prevention blades of the plurality of co-rotation prevention blades, and each of the rotary blades in the central axis direction is the distance between the co-rotation prevention blades. the second co-rotation preventing blade and the rather larger than distance between the central axis direction of each rotor blade is the remaining co-rotation prevention wings,
Each rotor has an extension plate that extends from the end edge on the co-rotation prevention blade side within a range that does not come into contact with the co-rotation prevention blade when relatively rotated.
Each extension plate can be elastically deformed so that the portion on the tip side in the extension direction is displaced in the direction opposite to the rotation direction of the rotary blade with respect to the co-rotation prevention blade.
The position of the extension plate in each rotor in the direction orthogonal to the central axis is arranged in one rotor when each rotor rotates around the central axis at the same position in the central axis direction. A ground improvement machine in which the area through which the extended plate is passed is set so as not to overlap with the area through which the extended plate is arranged on another rotor.