JP5222181B2 - Boring hole expansion device - Google Patents

Description

  The present invention relates to a boring hole expanding apparatus. More specifically, the present invention relates to an apparatus suitable for use in expanding a borehole drilled in a rock mass.

  When conducting various surveys in the borehole in the bedrock, it is accurately observed that the hole wall is contaminated with cuttings, slime, etc. due to drilling or clay or polymer intentionally mixed in the drilling water. Or data collection may not be possible. Specifically, for example, in the observation of the hole wall with a borehole camera or the like, if the hole wall is dirty, there is a problem that the rock type such as rock type and fault cannot be observed and discriminated. In the hole permeability test, the hole wall becomes dirty. If the hole wall is dirty, there is a problem that the exact water permeability of the rock mass is not known. There is a problem of not knowing.

  And when the hole wall is dirty and there is a problem in the contents of the investigation to be carried out, the hole is often washed with fresh water after boring, but that alone is often insufficient.

  For this reason, reboring, that is, hole expansion, is performed in order to remove a gap or the like attached to the hole wall by a method other than cleaning.

  Here, when the hole is re-bored and expanded, if the gap caused by the expansion flows together with the drilling water and adheres to the hole wall again, the purpose of re-boring cannot be achieved. There is known a mechanism for preventing drill water containing slurries from entering a hole wall by controlling the flow of water.

  For example, as shown in FIG. 5, as shown in FIG. 5, in the front casing 109 located at the bottom of the drilling hole, A drill bit 101 attached to one end of the center barrel 102, a motor 104 that rotates the drill bit 101, and a swivel 103 that is connected to the lower part of the motor 104 are provided, and a clamp that supports a casing located on the ground side is provided. A device (not shown) is provided, and fresh water is introduced into the casing and supplied to the bottom of the drilling hole through a gap 107 between the casing and the casing formed in the center barrel 102, and formed in the drilling bit 101. The central hole 108 formed so as to penetrate the center barrel 102 and the swivel 103 from the suction hole 106 and the exhaust to the ground The drilling water containing earth and sand milled by way of the pipe 105 there is to make sucked up by a vacuum pump (not shown) (Patent Document 1).

JP 2007-170087

  However, when a swivel is used for the drainage system of drilling water as in the boring device of Patent Document 1, there is a problem that the swivel is clogged and causes a failure. For this reason, it is difficult to say that the driving stability of the apparatus is high.

  In addition, in the boring device of Patent Document 1, it is possible to prevent the drilling water including the slip from flowing into the hole wall. On the other hand, when deep drilling is performed, the drilling water is removed only by the function of the vacuum pump. Since it is difficult to drain from the inside, there is a problem that work efficiency is reduced or a high-output vacuum pump is required. For this reason, it leads to the cost increase of apparatus maintenance.

  Therefore, the present invention provides a boring expansion device that can prevent a failure due to clogging in a drainage system of drilling water and can efficiently drain the drilling water from the borehole. Objective.

  In order to achieve such an object, a boring hole expanding device according to claim 1 includes a columnar housing, a rotating shaft supported axially by the housing and extending axially from the housing, A rotating cylindrical portion disposed around the rotating shaft and supported by the housing so as to be axially rotatable and having a drilling bit attached in a circumferential direction so as to be positioned below the lower end surface of the housing; It has an inner magnet attached to the rotating shaft and an outer magnet attached to the rotating cylindrical part. The inner magnet and the outer magnet constitute a magnet coupling, and the inner shaft is rotated by the driving device to rotate the inner shaft. By rotating around, the excavation bit is rotated around the axis of the rotating cylindrical part to which the outer magnet is attached.

  Therefore, according to this boring hole expanding apparatus, since the action of the magnet coupling is utilized, a new drive system can be realized for the rotating shaft of the boring apparatus.

  According to a second aspect of the present invention, there is provided the boring hole expanding device according to the first aspect, wherein the housing has an opening at the lower end surface and a supply channel for supplying the drilling water to the drill bit, A drainage channel for draining the excavated water after being used from the borehole, and a shaft that is disposed between the rotary shaft and the rotary cylindrical portion with a gap between them and fixed to the housing A cover and a drainage pump portion communicating with the drainage channel and communicating with a gap between the rotating cylindrical portion and the shaft cover are provided, and the drilling water is supplied to the drilling bit from the opening of the water supply channel on the lower end surface of the housing. The drilling water after being used for excavation is sucked from the through-hole provided in the peripheral wall of the rotating cylindrical portion, passed through the gap between the rotating cylindrical portion and the shaft cover, and accumulated in the drainage pump portion, and then the drainage channel To be discharged.

  Therefore, according to this boring expansion device, the housing having the water supply channel and the drainage channel does not rotate when excavating for expansion, that is, the water supply channel is not rotated by the rotation shaft and the rotation cylindrical portion. And since the drainage channel is not affected, the water supply channel and the drainage channel are configured without using a swivel.

  According to the boring hole expanding device of the present invention, since the water supply channel and the drainage channel can be configured without using a swivel, the configuration of the water supply / drainage system can be simplified, and in particular, clogging in the swivel can be prevented. By avoiding this, it becomes possible to improve the driving stability of the apparatus.

It is a longitudinal cross-sectional view which shows an example of embodiment of the boring hole expanding apparatus of this invention, and is a figure explaining the structure of a rotating system especially. It is a longitudinal cross-sectional view which shows an example of embodiment of the boring hole expansion apparatus of this invention, and is a figure explaining the structure of a water supply / drainage system especially. It is a cross-sectional view which shows an example of embodiment of the boring hole expansion apparatus of this invention. (A) is a cross-sectional view which shows the state cut | disconnected by the II line | wire of FIG. (B) is a cross-sectional view showing a state cut along line 2-2 in FIG. (C) is a cross-sectional view showing a state cut along line 3-3 in FIG. It is an external appearance perspective view of the lower part of the boring hole expanding apparatus of embodiment. It is a longitudinal cross-sectional view which shows the conventional boring apparatus.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

  1 to 4 show an example of an embodiment of a boring hole expanding apparatus of the present invention. The boring hole expanding device 1 includes a columnar housing, a rotating shaft 21 supported by the housing so as to be axially rotatable and extending in the axial direction from the housing, and a housing disposed around the rotating shaft 21. A rotating cylindrical portion 31 that is supported by the body so as to be axially rotatable and has a drilling bit 32 that is disposed in the circumferential direction so as to be positioned below the lower end surface of the housing, and is attached to the rotating shaft 21. The inner magnet 9a and the outer magnet 9b attached to the rotating cylindrical portion 31. The inner magnet 9a and the outer magnet 9b constitute a magnet coupling 9, and the motor 22 serving as a driving device shafts the rotating shaft 21. By rotating and rotating the inner magnet 9a, the rotating cylindrical portion 31 to which the outer magnet 9b is attached is rotated. It is intended to the drill bit 32 circumferential rotation.

  Here, in the following description, upper and lower are defined based on the attitude of the boring hole expanding device 1 when performing excavation for expanding the boring hole. Specifically, since the boring hole expanding device 1 stands in the vertical direction and digs in the direction of the arrow 19 shown in FIG. 1, the center riser 6 side is on the lower side and the extension casing connecting part 8 side is on the upper side.

  FIG. 2 shows a longitudinal section at the position of line 5-5 shown in the transverse section at the position of line 4-4 shown in the longitudinal section of FIG.

  The boring hole expanding device 1 includes an internal rotation system and an external rotation system that rotate about an axis parallel to the axis of the case, as a structure of the rotation system, in addition to the case that forms the main body of the device. A magnet coupling 9 is provided for operating the internal rotation system and the external rotation system in conjunction with each other.

  The casing is roughly divided into a casing base 2, a drainage pump peripheral wall 3 attached to the lower end of the casing base 2, a lower casing 4 connected to the lower end of the drainage pump peripheral wall 3, and a casing The upper casing 7 is attached to the upper end portion of the base 2 and the extension casing connecting portion 8 is attached to the upper end of the upper casing 7. The lower casing 4, the drainage pump peripheral wall 3, the casing base 2, the upper casing 7, and the extension casing coupling portion 8 form a columnar shape as a whole in a stacked state.

  Further, the boring hole expanding device 1 has a structure extending downward from the inside of the housing, and passes through the drainage pump portion peripheral wall 3 and the lower casing 4 attached to the lower portion of the housing base portion 2, and below the lower casing 4. A shaft cover 10 extending to the lower end of the shaft cover 10 and a magnet storage portion 5 attached to the lower end of the shaft cover 10.

  The casing and the structure extending downward from the inside of the casing completely covers the internal rotation system, prevents water from entering the interior, and the internal rotation system includes drilling water, especially drilling water containing sludge. To prevent exposure to water. Also, bearings are provided between the housing and the internal rotation system and the external rotation system, and when the device is driven to perform excavation for expanding the borehole, the internal rotation system and the external rotation system are While the shaft rotates, the housing does not rotate.

  The internal rotation system roughly includes a rotation shaft 21, a motor 22 for rotating the rotation shaft 21, and a speed reducer 23 and a transmission shaft 24 for transmitting the drive of the motor 22 to the rotation shaft 21. Become. In the present embodiment, the boring hole expanding device 1 includes three motors 22.

  The external rotating system is roughly divided into a rotating cylindrical portion 31, an excavation bit 32 that is arranged and attached to the intermediate portion of the peripheral wall of the rotating cylindrical portion 31, and a drain provided at the upper end of the rotating cylindrical portion 31. And blades 33a.

  The inner magnet 9a is attached to the outer peripheral surface of the lower end portion of the rotating shaft 21 of the internal rotating system, and the outer magnet 9b is attached to the position facing the inner magnet 9a of the inner peripheral surface of the lower end portion of the rotating cylindrical portion 31 of the outer rotating system. The inner magnet 9a and the outer magnet 9b are paired to constitute a main part of the magnet coupling 9, and the rotating cylindrical portion 31 rotates in conjunction with the shaft rotation of the rotating shaft 21 driven by the motor 22. .

  The casing base 2 is a component located approximately in the middle of the boring hole expanding device 1, and is formed in a columnar shape that is short compared to the diameter.

  The housing base 2 has a through hole 2a in the axial direction that passes through the transmission shaft 24 and the rotating shaft 21 in a connected state, that is, in the vertical direction.

  The casing base 2 further sucks up the drilling water and the vertical through-passage 2b that constitutes a part of the water supply channel 11 for supplying the drilling water to the drilling bit 32 during excavation for expanding the hole. It has a vertical passage 2c that constitutes a part of the drainage channel 13 for draining from the borehole.

  An upper edge fitting step 2d is formed on the upper edge portion of the outer peripheral surface of the casing base 2 and is a step in the circumferential direction, and the lower edge portion of the upper casing 7 is fitted. The upper edge fitting step 2d is attached with an O-ring 2e for ensuring the water tightness of the connecting portion of the upper casing 7 when the upper casing 7 is fitted to ensure the waterproofness of the upper casing 7.

  The upper casing 7 has a columnar shape, and an outer peripheral edge protruding from the lower end surface is fitted to the upper edge fitting step 2 d of the casing base 2 and attached to the upper portion of the casing base 2.

  The upper casing 7 has a through hole 7a for storing the motor 22 and the speed reducer 23 in a connected state. In the present embodiment, the boring hole expanding device 1 includes three motors 22, and equilateral triangles around the axis of the upper casing 7 at equal intervals in the circumferential direction, in other words, an equilateral triangle centered on the position of the axis. Are provided with three through holes 7a, 7a, 7a parallel to the axis.

  The upper casing 7 further has a through hole 7 c in the axial direction that constitutes a part of the water supply channel 11, that is, a vertical through hole 7 c that constitutes a part of the drainage channel 13. The water supply passage through-hole 7c and the drain passage through-hole 7d are provided between the adjacent motor storage through-holes 7a and 7a and at positions near the outer edge of the upper casing 7 in the direction perpendicular to the axis.

  The upper casing 7 has an opening at the lower end surface and a gear storage recess 7b for storing the transmission shaft 24 at the axial center position.

  Each motor 22 is fixed in each motor storage through hole 7 a of the upper casing 7. A reduction gear 23 is attached to the lower side of each motor 22 so as to be connected to the drive shaft of each motor 22.

  The transmission shaft 24 transmits the drive of the motor 22 output via the speed reducer 23 to the rotary shaft 21. The transmission shaft 24 has a gear 24a that protrudes from the central axis in the radial direction (in other words, the direction perpendicular to the axis) and meshes with the gear of the speed reducer 23 at a position near the upper end, and the rotary shaft 21 is inserted into the lower end portion. A recessed portion 24b to be fitted is provided at the axial center position.

  Of the transmission shaft 24, the upper part where the gear 24 a that meshes with the gear of the speed reducer 23 is stored in the gear storage recess 7 b at the lower end of the upper casing 7, and the lower part to which the rotary shaft 21 is connected is the housing. It is stored in the through hole 2 a of the base 2. Here, so that the gear of each reduction gear 23 and the gear 24a of the transmission shaft can be engaged with each other, the portion near the lower end of each motor storage through-hole 7a and the portion where the gear of the reduction gear 23 is located and the gear storage. The recess 7b is formed in communication with the side.

  The transmission shaft 24 is supported by a bearing 24c such as a ball bearing embedded and attached to the upper surface of the gear storage recess 7b so that the central shaft protruding above the gear 24a is supported so as to be rotatable, and the inner periphery of the through hole 2a. The lower center shaft of the gear 24a is supported by the bearing 24d attached to the surface so as to be rotatable about the shaft, thereby being supported so as to be rotatable about the housing base 2 and the upper casing 7. And the drive of the motor 22 is transmitted and the rotating shaft 21 is axially rotated.

  An extension casing connecting portion 8 is attached to the upper end portion of the upper casing 7. The extension casing connecting portion 8 is a joint for connecting the extension casing 18 to the upper end surface when the boring hole expanding device 1 is gradually advanced into the boring hole in accordance with the progress of excavation for hole expansion. . The extension casing coupling portion 8 is formed in a columnar shape that is short compared to the diameter.

  A lower edge fitting step 8c is formed on the lower edge portion of the outer peripheral surface of the extension casing coupling portion 8 and is a step in the circumferential direction, and the upper edge portion of the upper casing 7 is fitted. The lower edge fitting step 8c is attached with an O-ring 8d for ensuring the water tightness of the connecting portion between the upper casing 7 and the waterproofness of the upper casing 7 when the upper casing 7 is fitted.

  The extension casing connecting portion 8 constitutes a part of the water supply channel 11 and constitutes a part of the drainage channel 13 and the flow path 8a leading from the upper end surface to the lower end surface. And a flow path 8b communicating with the upper end surface.

  On the other hand, a lower edge fitting step 2f, which is a circumferential belt-like step and is fitted to the upper end portion of the drainage pump portion peripheral wall 3, is formed at the peripheral edge of the lower end surface of the housing base 2.

  The drainage pump peripheral wall 3 is composed of a belt-shaped peripheral wall 3a and a bottom surface 3b. A through hole for allowing the rotary shaft 21, the shaft cover 10, and the rotary cylindrical portion 31 to pass through is formed at the center of the bottom surface 3b. Moreover, the drainage pump part surrounding wall 3 has the through-hole 3e of the up-down direction which comprises some water supply paths 11 in the surrounding wall 3a.

  Here, the inside of the drainage pump section peripheral wall 3 is a drainage pump section 33 that is a space in which drilling water that is supplied to the excavation bit 32 and used for excavation for expanding holes is drained from the borehole. To play a role. In addition, the drainage pump part 33 that is the internal space of the drainage pump part peripheral wall 3 and the through passage 2c of the casing base part 2 communicate with each other in a state where the upper end part of the drainage pump part peripheral wall 3 is fitted to the lower end of the casing base part 2. To do.

  The drainage pump part 33 has drainage vanes 33a attached to the outer peripheral surface of the upper cylindrical part 31a of the upper part of the rotary cylindrical part 31 that passes through the through hole of the bottom surface 3b and enters the peripheral wall 3 of the drainage pump part. Provided. The drainage blade 33a is formed of a flexible member having a height equivalent to that of the peripheral wall 3a of the drainage pump portion peripheral wall 3. The drainage blade 33 a functions as a part that divides the internal space of the drainage pump part peripheral wall 3 as the drainage pump part 33. In the present embodiment, three drainage blades 33a are attached to the outer peripheral surface of the upper cylindrical portion 31a of the rotating cylindrical portion 31 at equal intervals in the circumferential direction.

  A crescent protrusion 33b is formed on a part of the inner peripheral surface of the peripheral wall 3a of the drainage pump portion peripheral wall 3. The crescent protrusion 33b is located between the opening position of the through passage 2c of the housing base 2 fitted to the upper end of the drainage pump part peripheral wall 3, and between the inner peripheral surface of the upper cylindrical part 31a and the outer peripheral surface of the shaft cover 10. It is formed between the opening position of the suction opening 33 c communicating with the drainage space 12. The suction opening 33 c has an opening on the upper surface of the drainage pump part 33.

  As a result, when the rotating cylindrical portion 31 rotates and the drainage blade 33a rotates in the drainage pump portion 33 (in the embodiment, it rotates clockwise in the cross section shown in FIG. 3B), each drainage The volume of the space divided by the blades 33a varies between the crescent lug 33b portion and the front and rear thereof. Since the pressure changes as the volume of the space changes between the crescent protrusion 33b and the front and rear thereof, the suction opening of the space partitioned by the drainage blade 33a in the cross section shown in FIG. Since the volume of the space including the position of the portion 33c increases, the drilling water is sucked up from the drainage space 12 and sucked into the drainage pump portion 33, and the volume of the space including the position of the through-passage 2c decreases. Is discharged to the through passage 2c. Note that the drainage space 12 and the drainage pump portion 33 communicate with each other only through the suction opening 33c, and the watertightness of each other is ensured at other locations. With the function of the drainage pump unit 33, in the boring hole expanding device of the present invention, for example, a vacuum pump or the like for draining the drilling water from the borehole becomes unnecessary.

  Then, the upper casing 7 is fitted to the upper end of the casing base 2 and the extension casing connecting portion 8 is fitted to the upper end of the upper casing 7 and connected to the through passage 2c of the casing base 2 and the upper casing. 7 through-hole 7 d and the flow path 8 b of the extension casing connecting portion 8 communicate with each other to form a drainage channel 13. Note that the upper end opening of the flow path 8b of the extension casing connecting portion 8 communicates with a through hole that forms a drainage channel 13 provided in the extension casing 18 connected to the upper end of the extension casing connecting portion 8, thereby boring. The drilling water passes through the hole expanding device 1 and the drainage passage 13 in the extension casing 18 and is drained from the borehole.

  At the peripheral edge of the lower end surface of the drainage pump part peripheral wall 3, a lower edge fitting step 3 d is formed which is a step in the circumferential direction and into which the upper end of the peripheral wall of the lower casing 4 is fitted.

  The lower casing 4 is formed in a cylindrical shape having a central through hole 4a. Further, the lower casing 4 has a through-hole 4e in the axial direction, that is, the vertical direction constituting a part of the water supply channel 11, in the cylindrical peripheral wall.

  The lower casing 4, the drainage pump part peripheral wall 3, the housing base 2, and the upper casing 7 are fitted and joined to each other, and the through hole 4 e of the lower casing 4 and the through hole 3 e of the drainage pump part peripheral wall 3 The water passage 11 is formed by the communication between the through passage 2 b of the housing base 2, the through hole 7 c of the upper casing 7, and the flow passage 8 a of the extension casing connection portion 8. Note that the upper end opening of the flow path 8a of the extension casing connecting portion 8 communicates with a through hole that forms a water supply path 11 provided in the extension casing 18 connected to the upper end of the extension casing connecting portion 8, thereby boring. Drilling water is supplied to the drill bit 32 from a water supply facility (not shown) such as a pump provided outside the hole through the extension casing 18 and the water supply passage 11 of the boring hole expanding device 1.

  In the present embodiment, six female screw holes are formed at equal intervals in the circumferential direction and in the vertical direction at the peripheral edge portion (that is, the lower edge fitting step 2f portion) of the lower end surface of the housing base 2. Further, six through holes are formed in the peripheral wall 3a portion of the drainage pump portion peripheral wall 3 at equal intervals in the circumferential direction and in the vertical direction. Furthermore, six through holes are formed in the cylindrical peripheral wall of the lower casing 4 at equal intervals in the circumferential direction and in the vertical direction. Then, the casing base 2, the drainage pump peripheral wall 3 and the lower casing 4 are joined together, and the connecting shaft 14 having a male screw formed at the tip is inserted into the through-hole from the lower casing 4 side, and the tip of the connecting shaft 14 is inserted. These three parts 2, 3, 4 are fixed by screwing the male screw part into the female screw hole of the housing base 2.

  The rotating shaft 21 has an upper end connected to the transmission shaft 24 in the through hole 2 a of the housing base 2 and extends downward from the through hole 2 a to the housing base 2.

  Further, the rotary shaft 21 has a magnet fixing portion 21a having a diameter slightly larger than that of other portions at a position near the lower end.

  The prismatic inner magnet 9a is attached to the outer peripheral surface of the magnet fixing portion 21a at equal intervals in the circumferential direction in parallel with the axial center direction of the rotating shaft 21. In the present embodiment, eight inner magnets 9a are attached.

  The lower portion of the through hole 2 a of the housing base 2 is formed with a diameter larger than the diameter of the rotary shaft 21. The cylindrical shaft cover 10 surrounding the side surface of the rotating shaft 21 is inserted into a portion where the diameter of the lower portion of the through hole 2a is increased, and is extended and fixed toward the lower side of the casing base 2. The And the O-ring 2i for ensuring the watertightness of the connection part of both when the shaft cover 10 is inserted and fitted together is attached to the inner peripheral surface of the through hole 2a. Here, a gap is provided between the inner peripheral surface of the shaft cover 10 and the outer peripheral surface of the rotary shaft 21 so that the rotary shaft 21 can rotate freely.

  The magnet storage portion 5 is attached to the lower end portion of the shaft cover 10. The magnet storage unit 5 stores therein a magnet fixing unit 21 a and an inner magnet 9 a that are attached to a position near the lower end of the rotary shaft 21.

  The magnet storage part 5 has an insertion hole 5a for opening the rotary shaft 21 with an opening on the upper end surface. The upper portion of the insertion hole 5 a is formed with a diameter larger than that of the rotary shaft 21. And the magnet storage part 5 is attached to the lower end part of the shaft cover 10 by inserting and fixing the shaft cover 10 in the part where the diameter of the insertion hole 5a is large. And the O-ring 5b for ensuring the watertightness of the connection part of both when the shaft cover 10 is fitted together is attached to the inner peripheral surface of the insertion hole 5a.

  The magnet storage part 5 has a hollow part 5c communicating with the insertion hole 5a, and stores the magnet fixing part 21a and the inner magnet 9a in the hollow part 5c. Here, the wall surface of the hollow portion 5c (that is, the inner peripheral surface of the magnet storage portion 5) and the outer peripheral surface of the inner magnet 9a so that the rotating shaft 21 and the inner magnet 9a attached to the shaft can freely circulate. A gap is provided between the two.

  The rotary shaft 21 is supported by a bearing 5d attached to the inner peripheral surface of the insertion hole 5a in the upper portion of the hollow portion 5c so as to be axially rotatable, and is fixed to the magnet fixing portion 21a by a bearing 5e embedded and attached to the lower surface of the hollow portion 5c. A portion projecting to the lower portion of the magnet is supported so as to be rotatable about the shaft, and is thereby supported so as to be rotatable relative to the magnet storage portion 5.

  The rotating cylindrical portion 31 is broadly divided into an upper cylindrical portion 31a, a drilling bit mounting portion 31b formed at the lower end of the upper cylindrical portion 31a, and a lower cylindrical portion 31c formed below the drilling bit mounting portion 31b. Consists of.

  The upper cylindrical portion 31 a of the rotating cylindrical portion 31 is inserted between the lower casing 4 and the shaft cover 10. Further, the upper end portion of the upper cylindrical portion 31 a enters the drainage pump portion 33.

  The upper cylindrical portion 31a is supported by a pair of bearings 4b and 4c attached to the upper opening portion and the lower opening portion on the inner peripheral surface of the central through hole 4a of the lower casing 4 so as to be axially rotatable.

  The excavation bit attachment portion 31b is formed so as to be connected to the lower end of the upper cylindrical portion 31a, and is formed to project radially from the upper cylindrical portion 31a at a position close to the lower end surface of the lower casing 4. In the present embodiment, eight excavation bits 32 are screwed and attached to the side surface (that is, the peripheral surface) of the excavation bit attachment portion 31b at equal intervals in the circumferential direction. In the present invention, the excavation bit 32 is a general bit used for excavation or expansion of a borehole.

  The drilling water supplied to the drilling bit 32 at the time of excavation for expanding the hole is drained from the borehole at the boundary between the drilling bit mounting part 31b and the lower cylindrical part 31c on the peripheral wall of the rotating cylindrical part 31. For this purpose, a through-hole 31 d is provided for taking in the rotating cylindrical portion 31. The through holes 31d are provided below the attachment positions of the respective excavation bits 32. In the present embodiment, eight through holes 31d are provided side by side in the circumferential direction.

  The lower cylindrical portion 31c is formed to be connected to the lower side of the excavation bit attaching portion 31b so as to surround and cover the outer periphery of the magnet storage portion 5.

  On the inner peripheral surface of the lower cylindrical portion 31c, a prismatic outer magnet 9b is attached in parallel with the axial direction of the lower cylindrical portion 31c at an equal interval in the circumferential direction and at a height facing the inner magnet 9a. Further, a dust seal 31e for preventing a large gap from entering the space where the inner magnet 9a is attached on the upper side and the lower side of the position where the inner magnet 9a is attached on the inner peripheral surface of the lower cylindrical portion 31c is provided in the circumferential direction. Attached to. This prevents a large gap from entering between the outer peripheral surface of the magnet storage portion 5 and the inner peripheral surface of the inner magnet 9a, thereby preventing the rotation of the lower cylindrical portion 31c. Smooth rotation is ensured.

  In the present embodiment, eight outer magnets 9b are attached to correspond to the inner magnets 9a. And the magnet coupling 9 is comprised by the inner side magnet 9a and the outer side magnet 9b.

  Here, in order to suck the excavated water supplied to the excavation bit 32 at the time of excavation for expanding the hole and including the gap generated by excavation from the through-hole 31 d and send it to the drainage pump unit 33, A gap is provided between the inner peripheral surface and the outer peripheral surface of the shaft cover 10 and the magnet storage portion 5 to allow excavation water including gaps to pass therethrough, and the drainage space 12 is formed by the gap.

  A center riser 6 is attached to the lower end of the magnet storage unit 5. The center riser 6 is used for positioning the boring hole expanding device 1 at the center of the already drilled hole when performing excavation for expanding the hole. Can be evenly drilled and expanded. In the present embodiment, the center riser 6 is attached to the lower end surface of the magnet storage portion 5 by screwing.

  With the above configuration, the boring hole expanding device 1 according to the present invention includes a housing base portion 2, a drainage pump portion peripheral wall 3, a lower casing 4, an upper casing 7, and an extended casing connecting portion 8 that are housings. A water supply path 11 having an opening at the lower end surface for supplying drilling water to the drill bit 32, a drainage path 13 for draining the drilling water after being used for drilling from the borehole, and a rotating shaft The shaft cover 10 is disposed between the rotary cylinder portion 31 and the rotary cylinder portion 31 with a gap between them and is fixed to the housing base 2, and communicates with the drainage channel 13 and is also connected to the rotary cylinder portion 31 and the shaft cover 10. A drainage pump portion 33 communicating with the drainage space 12 which is a gap between the lower casing 4 and the drilling water supplied to the drilling bit 32 from the opening of the water supply channel 11 on the lower end surface of the lower casing 4 and used for excavation. Then, the excavated water is sucked from a through-hole 31d provided in the peripheral wall of the rotary cylindrical portion 31 and passed through the drainage space 12 which is a gap between the rotary cylindrical portion 31 and the shaft cover 10 and collected in the drainage pump portion 33. Then, it can be discharged into the drainage channel 13.

  With the above-described structure, in the boring hole expanding device 1 of the present invention, the motor 22, the speed reducer 23, the transmission shaft 24, the rotating shaft 21, and the inner magnet 9a that constitute the internal rotation system are the extensions that constitute the casing. The casing connecting portion 8, the upper casing 7, the casing base 2, the shaft cover 10, and the magnet storage portion 5 maintain water tightness and are completely covered in a waterproof state.

  And in the boring hole expansion apparatus 1 of this invention, the lower end of the water supply path 11 in which the drilling water 15a (for example, fresh water; represented by the white arrow in FIG. 2) reaches the lower end of the lower casing 4 through the water supply path 11. Specifically, it is supplied to the excavation bit 32 from the lower end opening of the through hole 4e. The lower end opening of the through hole 4e to which the drilling water 15a is supplied is located in the vicinity of the drill bit 32. Then, when the excavation bit 32 performs excavation, the excavation occurs, and the excavation water supplied to the excavation bit 32 includes the excursion.

  The drilling water 15b including the excavation gap (represented by a black arrow in FIG. 2) is sucked into the drainage space 12 in the rotary cylindrical portion 31 from the through-hole 31d having an opening below the drilling bit 32. The excavated water 15b including the gap passes through the gap between the outer peripheral surface of the shaft cover 10 and the inner peripheral surface of the upper cylindrical portion 31a, that is, the drainage space 12, and is sucked up by the drainage pump unit 33.

  Then, the excavated water 15b including the gap sucked up by the drain pump unit 33 is such that the drain vane 33a rotates in the drain pump unit 33 along with the shaft rotation of the rotating cylindrical unit 31 by the action of the magnet coupling 9. Is sent from the lower end opening of the drainage channel 13 (specifically, the lower end opening of the through passage 2c of the housing base 2) to the drainage channel 13. The excavated water 15b including the gap is further drained from the borehole through the drainage passage in the extension casing.

  According to the boring hole expanding apparatus 1 of the present invention, the upper casing 7 attached to the housing base 2, the drainage pump part peripheral wall 3, and the lower casing 4 attached to the upper casing 7 are being excavated for expanding the holes. In addition, the shaft cover 10 attached to the housing base 2 and the magnet storage part 5 attached to the shaft cover 10 and the center riser 6 attached to the shaft cover 10 rotate during the excavation for hole expansion. There is no.

  And according to the boring hole expanding apparatus 1 of this invention, with the above structure, the drive of the motor 22 is transmitted via the speed reducer 23, the transmission shaft 24, and the rotating shaft 21, and the inner magnet 9a rotates in a circumferential direction (in other words, For example, the outer magnet 9b revolves around the axis of the rotating shaft, and the outer magnet 9b rotates by the action of the magnet coupling 9 formed by the inner magnet 9a and the outer magnet 9b. As a result, the rotating cylindrical portion 31 rotates axially, and the excavation bit 32 rotates along with the rotation, whereby the peripheral wall of the boring hole is excavated and expanded.

  According to the boring hole expanding apparatus of the present invention having the above configuration, the water supply channel 11 and the drain channel 13 can be configured without using a swivel. For this reason, the configuration of the water supply / drainage system can be simplified, and in particular, the drive stability of the apparatus can be improved by avoiding clogging of the slip in the swivel.

  In addition, although the above-mentioned form is an example of the suitable form of this invention, it is not limited to this, A various deformation | transformation implementation is possible in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Boring hole expansion apparatus 2 Case base part 3 Drain pump part peripheral wall 4 Lower casing 5 Magnet storage part 7 Upper casing 9 Magnet coupling 9a Inner magnet 9b Outer magnet 21 Rotating shaft 22 Motor 31 Rotating cylindrical part 32 Excavation bit 33 Drain pump part

Claims (2)

  A columnar casing, a rotating shaft supported axially by the casing and extending axially from the casing, and disposed around the rotating shaft and supported by the casing so as to be axially rotatable. And a rotating cylindrical part to which a drilling bit arranged in a circumferential direction so as to be positioned below the lower end surface of the casing is attached, and an inner magnet attached to the rotating shaft, and the rotating cylindrical part An outer magnet attached to the inner magnet, the inner magnet and the outer magnet constitute a magnet coupling, and the outer magnet is rotated by rotating the shaft around the rotating shaft by a driving device. Boring hole expansion, characterized in that the excavating bit is rotated by rotating the attached rotating cylindrical portion. Location.   The housing has an opening in the lower end surface and a water supply channel for supplying drilling water to the drilling bit, and drainage for draining the drilling water after being used for drilling from the borehole A shaft cover disposed between the rotary shaft and the rotary cylindrical portion with a gap between them and fixed to the housing; the drain cover and the rotary cylindrical portion; A drainage pump portion communicating with a gap between the shaft cover and the drainage pump portion for supplying the excavation water to the excavation bit from the opening of the water supply channel at the lower end surface of the casing and Excavating water from a through-hole provided in the peripheral wall of the rotating cylindrical portion, passing through a gap between the rotating cylindrical portion and the shaft cover, collecting the drilling water in the drainage pump portion, and then discharging to the drainage channel. The feature of claim 1 Boring reaming apparatus.