JP2014095212A - Drive transmission mechanism of double-pipe drilling machine, and double-pipe drilling machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress jamming by excellently discharging slime from between an inner pipe and an outer pipe and to simplify a mechanism which transmits turning force to the inner pipe and outer pipe.SOLUTION: There is provided a drive transmission mechanism 10 installed in a double-pipe driving machine 100. The double-pipe driving machine 100 is configured to have a thrust based upon an impact force that a hydraulic hammer 130 connected to an inner rod 120 applies to a pilot bit 140 and a turning force applied to the pilot bit 140 through the inner rod 120, to have a discharge path for slime formed between an inner pipe and an outer pipe of a double pipe, and to allow water to flow to the discharge path from between the hydraulic hammer 130 and pilot bit 140 when the hydraulic hammer 130 is retracted from the pilot bit 140. The drive transmission mechanism 10 transmits the turning force and the thrust in a drilling direction from a drive part 200 of the double-pipe drilling machine 10 to the double pipe, and connects the inner rod 120 etc., and an outer rod 110 etc., to rotate in one body and also to move relatively along their axes.

Description

  The present invention relates to a drive transmission mechanism for a double pipe drilling machine and a double pipe drilling machine.

  2. Description of the Related Art A double pipe drilling machine is known that drills ground or rock using a hammering force from a hydraulic hammer and a rotational force from a double pipe as driving forces (see, for example, Patent Document 1). In the double-pipe drilling machine described in Patent Document 1, a hammer is applied to the bit portion by a hydraulic hammer connected to the tip of the inner tube, and the rotary drive device disposed at the rear end portion of the double tube A rotational force is applied to the bit portion through the tube, and further, a rotational force is applied to the outer tube by the rotation driving device. Here, by rotating the outer pipe, the restraint from the ground or the rock on the outer pipe is relaxed, and the propulsive force is increased.

JP 2004-36204 A

  In the double-pipe drilling machine described in Patent Document 1, two drive transmission mechanisms are required by separately connecting the inner pipe and the outer pipe to the rotary drive device, which complicates the mechanism. ing. In order to solve this problem, it can be considered that the inner tube and the outer tube are integrated and only one of them is connected to the rotary drive device. In this case, the following problem arises.

  When the slime is discharged between the inner pipe and the outer pipe in a double pipe drilling machine, if the slime accumulates in the middle, the slime discharge may be hindered and jamming may occur. If the tube is rotated relative to the tube, the edges of the slime and the inner tube and the outer tube are cut off, so that slime is difficult to accumulate. However, if the inner tube and the outer tube are rotated together, the slime and the inner tube and The slime is easily deposited by rotating integrally with the outer tube. For this reason, it is necessary to remove the slime accumulated between the inner tube and the outer tube. As a method for this, the inner tube is moved backward relative to the outer tube, and a gap is formed between the hydraulic hammer and the bit portion. And water is ejected from the gap between the inner tube and the outer tube. However, if the inner pipe and the outer pipe are integrated, the inner pipe cannot be moved in the axial direction relative to the outer pipe, and a gap can be created between the hydraulic hammer and the bit portion. Disappear.

  The present invention has been made in view of the above circumstances, and suppresses the occurrence of jamming so that slime can be discharged well between the inner tube and the outer tube, and the inner tube and the outer tube. It is an object to simplify the mechanism for transmitting the rotational force to the motor.

  In order to solve the above problems, a drive transmission mechanism of a double pipe drilling machine according to the present invention includes an impact force applied to a bit part by a hydraulic hammer connected to an inner pipe of the double pipe, and the inner pipe. And a rotational force applied to the bit portion as a propulsive force, a slime discharge path is formed between the inner tube and the outer tube of the double tube, and the hydraulic hammer is relative to the bit portion. A double-pipe drilling machine configured such that, when retracted, a gap is formed between the hydraulic hammer and the bit portion so that water for cleaning the discharge passage flows out from the hydraulic hammer to the discharge passage. A drive transmission mechanism for transmitting a rotational force and a pushing force in the direction of excavation from the drive device of the double pipe drilling machine to the double pipe, wherein the inner pipe and the outer pipe are integrated It is characterized by being connected so that it can be rotated with relative movement in these axial directions. .

  The drive transmission mechanism of the double pipe drilling machine includes a first member projecting radially outward from the inner pipe at a position behind the outer pipe in the digging direction in the inner pipe, and more than the first member. A second member projecting radially outward from the outer tube at a position in front of the excavation direction and one of the first member and the second member are supported in parallel to the axis of the double tube. And a shaft member slidably inserted in a through hole formed in the other of the first member and the second member.

  In the drive transmission mechanism of the double pipe drilling machine, the first member and the second member may be an annular flange, and a plurality of the shaft members are arranged around the double pipe. May be arranged at intervals.

  In the drive transmission mechanism of the double pipe drilling machine, the shaft member may have one end fixed to the first member and slidably inserted into the through hole formed in the second member. You may provide the 3rd member distribute | arranged so that the said 1st member may be opposed to the axial direction of the said double pipe through the said 2nd member, and the other end of the said shaft member was fixed.

  Further, the double pipe drilling machine according to the present invention has a striking force given to the bit part by a hydraulic hammer connected to the inner pipe of the double pipe and a rotational force given to the bit part via the inner pipe. As a driving force, a slime discharge path is formed between the inner tube and the outer tube of the double tube, and when the hydraulic hammer is retracted relative to the bit portion, the hydraulic hammer and the Between the bit part, it is comprised so that the water which cleans the said discharge path may flow out into the said discharge path from the said hydraulic hammer, and it is comprised in the said double pipe from a drive device, and the pushing force in a digging direction And a drive transmission mechanism that connects the inner pipe and the outer pipe so that they can rotate together and can move relative to each other in the axial direction. It is characterized by that.

  According to the present invention, the slime can be discharged well between the inner tube and the outer tube to suppress jamming, and the mechanism for transmitting the rotational force to the inner tube and the outer tube is simplified. Can be

It is an elevation view (partial sectional view) showing a double pipe drilling machine according to an embodiment. It is sectional drawing and the front view which expand and show the front-end | tip of a drilling part. It is sectional drawing which expands and shows a drive transmission mechanism. It is a perspective view which shows a drive transmission mechanism. It is sectional drawing for demonstrating an effect | action of a drive transmission mechanism. It is sectional drawing for demonstrating an effect | action of a drive transmission mechanism. It is sectional drawing which shows the state of the double pipe drilling machine at the time of drilling. It is sectional drawing which shows the state of the double pipe drilling machine at the time of pipe cleaning.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an elevational view (partially sectional view) showing a double pipe drilling machine 1 according to an embodiment. As shown in this figure, the double-pipe drilling machine 1 includes a drilling unit 100 that drills ground, rock, and the like, a drive unit 200 that drives the drilling unit 100, and a driving force of the drive unit 200. A drive transmission mechanism 10 that transmits to the hole 100 is provided.

  The driving unit 200 includes a rotation driving device 210 that applies a rotation driving force to the hole drilling unit 100, a guide 220 that guides the rotation driving device 210 in a direction along its output shaft, and a guide for the rotation driving device 210. And a slide driving device 230 that slides along 220. The drive transmission mechanism 10 includes a double pipe connecting portion 20 that is coaxially connected to the output shaft of the rotary drive device 210 and rotates integrally with the output shaft.

  The hole cutting portion 100 includes an outer casing 110, an inner rod 120, a hydraulic hammer 130 and a pilot bit 140 disposed in the outer casing 110, a ring bit 150 disposed at the tip of the outer casing 110, and a cleaning swivel 160. The high pressure swivel 170 and the slime discharge port 180 are provided. The outer casing 110 and the inner rod 120 are both cylindrical tubes, and are arranged coaxially with respect to the output shaft of the rotary drive device 210 to constitute a double tube.

  The inner rod 120 has a rear end coaxially connected to the double pipe connecting portion 20 of the drive transmission mechanism 10 and rotates integrally with the double pipe connecting portion 20. The hydraulic hammer 130 has a rear end coaxially connected to the tip of the inner rod 120, and rotates integrally with the inner rod 120. The pilot bit 140 has a rear end coaxially connected to the tip of the hydraulic hammer 130 and rotates integrally with the hydraulic hammer 130. Here, the tip of the hydraulic hammer 130 and the pilot bit 140 are connected so that they can rotate together and can move relative to each other in the axial direction.

  The pilot bit 140 is inserted into a cylindrical ring bit 150 and rotates integrally with the ring bit 150. The tips of the pilot bit 140 and the ring bit 150 are arranged on the front side of the tip of the outer casing 110, and bits 142, 152 for cutting the ground or the rock are provided at the tips of the pilot bit 140 and the ring bit 150. Is provided.

  The double pipe connecting portion 20 of the drive transmission mechanism 10 has a tubular outer rod connecting portion 22 to which the rear end of the outer casing 110 is connected coaxially and a circular tube to which the rear end of the inner rod 120 is connected coaxially. And an inner rod connecting portion 24. The inner rod connecting part 24 extends from the rear end to the front end of the double pipe connecting part 20, and the outer rod connecting part 22 extends from the center of the double pipe connecting part 20 to the front end. The inner rod connecting portion 24, the inner rod 120, and the hydraulic hammer 130 are communicated with each other.

  The cleaning swivel 160 is connected to the inner rod connecting portion 24 and supplies water into the inner rod connecting portion 24. The high-pressure swivel 170 is connected to the rear end of the inner rod connecting portion 24 and supplies high-pressure water from the inner rod connecting portion 24 to the hydraulic hammer 130. The slime discharge port 180 is provided at the rear end of the outer rod connecting portion 22. Here, a space 101 serving as a discharge path for slime and water is formed between the outer peripheral surfaces of the hydraulic hammer 130, the inner rod 120, and the inner rod connecting portion 24 and the outer casing 110 and the outer rod connecting portion 22. The slime discharger 180 discharges slime and water from the space 101.

  FIG. 2 is an enlarged cross-sectional view and a front view showing the tip of the hole drilling portion 100. As shown in this figure, the pilot bit 140 is provided with a bit 142 on the front end surface, and the rear end side is inserted into the front end of the inner rod 120 and engaged therewith. Key grooves 143 are formed at predetermined intervals on the outer peripheral surface of the rear end side of the pilot bit 140, and keys (not shown) that engage with the key grooves 143 at predetermined intervals are formed on the inner peripheral surface at the tip of the inner rod 130. Has been. By engaging the key with the key groove 143, the rear side of the pilot bit 140 and the tip of the inner rod 130 can rotate together and can move relative to each other in the axial direction.

  The pilot bit 140 includes a plurality of (for example, three as shown) nozzles 145 arranged around the axis, and a plurality of (for example, three as shown) slime intakes formed on the outer peripheral surface. And a mouth 146. The plurality of nozzles 145 are opened at the front end surface of the pilot bit 140 and inject high-pressure water supplied from the high-pressure swivel 170 to the pilot bit 140 toward the front.

  The plurality of slime inlets 146 extend from the front end surface of the pilot bit 140 toward the space 101 between the outer peripheral surface of the hydraulic hammer 130 and the inner peripheral surface of the outer casing 110, and enter the space 101 from the excavation hole. Take in slime and water.

  The pilot bit 140 has a stepped portion 147 formed at an intermediate portion in the axial direction, and the tip end portion 130A of the hydraulic hammer 130 abuts on the stepped portion 147 so that the tip of the hydraulic hammer 130 and the center of the pilot bit 140 in the axial direction are located. Are connected to each other. In this state, when high-pressure water is supplied from the high-pressure swivel 170 to the hydraulic hammer 130, the hydraulic hammer 130 generates a striking force on the pilot bit 140.

  FIG. 3 is an enlarged sectional view showing the drive transmission mechanism 10, and FIG. 4 is a perspective view showing the drive transmission mechanism 10. As shown in these drawings, the drive transmission mechanism 10 includes the double pipe connecting portion 20 and a connecting portion 30 that connects the outer rod connecting portion 22 and the inner rod connecting portion 24 of the double pipe connecting portion 20. It has. The connecting portion 30 includes an annular flange 32 integrally provided at the rear end portion of the outer rod connecting portion 22, and an annular flange 34 integrally provided at an intermediate portion in the axial direction of the inner rod connecting portion 24. And an annular plate 36 through which the outer rod connecting portion 22 is inserted, and a plurality of shafts 38 that couple the flange 34 and the plate 36 together. The outer diameters of the flanges 32 and 34 and the plate 36 are substantially the same.

  The flange 34 integral with the inner rod connecting portion 24 is disposed on the rear end side with respect to the flange 32 integral with the outer rod connecting portion 22, and the plate 36 is disposed on the distal end side with respect to the flange 32. , Between the flange 34 and the plate 36. The plurality of shafts 38 are arranged around the outer rod connecting portion 22 at a predetermined interval (for example, 45 ° interval) in parallel to the double pipe connecting portion 20, and are attached to the front and rear ends of each shaft 38. The screw portion is formed, the tip is fixed to the plate 36 with a nut, and the rear end is fixed to the flange 34 by screwing into the screw hole formed in the flange 34.

  A through hole through which the shaft 38 is slidably inserted is formed in the flange 32, and the flange 32 is not rotatable around the double pipe connection portion 20 relative to the flange 34 and the plate 36. And it is movable in the axial direction of the double pipe connecting portion 20 along the shaft 38. As a result, the outer rod connecting portion 22 and the inner rod connecting portion 24 are coupled so that they cannot rotate relative to each other in the rotational direction of the double tube connecting portion 20 (can rotate together), and the axial direction of the double tube connecting portion 20 Are connected so as to be relatively movable. And since the rear end of the outer casing 110 is connected to the tip of the outer rod connecting portion 22 and the rear end of the inner rod 120 is connected to the tip of the inner rod connecting portion 24, the outer casing 110 and the inner rod 120 are connected. Are connected via the drive transmission mechanism 10 so as not to be relatively rotatable around the axis and relatively movable in the axial direction.

  Here, as shown in FIGS. 5 and 6, the movable range of the flange 32 is limited to a predetermined range between the flange 34 and the plate 36, so that the inner rod connecting portion 24 and the outer rod of the inner rod 120 are arranged. The relative movable range with respect to the connecting portion 22 and the outer casing 110 is limited to a predetermined range. As shown in FIG. 5, when the inner rod connecting portion 24 and the inner rod 120 are located in the forefront (left side in the figure) in the limited movable range, the water pressure connected to the tip of the inner rod 120 The tip portion 130 </ b> A of the hammer 130 contacts the stepped portion 147 of the pilot bit 140. On the other hand, as shown in FIG. 6, when the inner rod connecting portion 24 and the inner rod 120 are retracted from the frontmost position in the movable range, the tip portion 130 </ b> A of the hydraulic hammer 130 is the stepped portion of the pilot bit 140. A gap S is formed between them.

  FIG. 7 is a cross-sectional view showing a state of the double pipe drilling machine 1 during drilling, and FIG. 8 is a cross-sectional view showing a state of the double pipe drilling machine 1 during pipe cleaning. As shown in FIG. 7, at the time of drilling, the drilling unit 100 is rotated by the rotation driving device 210 while the drilling unit 100 is pushed in the digging direction by the slide driving device 230 (see FIG. 1). Further, high pressure water is supplied from the high pressure swivel 170 to the hydraulic hammer 130.

  At this time, the inner rod connecting portion 24 and the inner rod 120 are pushed forward in the movable range, thereby bringing the tip of the hydraulic hammer 130 into contact with the stepped portion 147 of the pilot bit 140. In this state, the hydraulic hammer 130 generates a striking force on the pilot bit 140. Further, the inner rod connecting portion 24 and the inner rod 120 are rotated to rotate the pilot bit 140 and the ring bit 150. Further, the pilot bit 140 ejects high-pressure water supplied to the hydraulic hammer 130 forward from the nozzle 145.

  As a result, the ground or the rock is drilled using the striking force applied to the pilot bit 140 by the hydraulic hammer 130 and the rotational force applied to the pilot bit 140 and the ring bit 150 by the rotation driving device 210 as propulsive forces. In addition, the slime formed by the bits 142 and 152 of the pilot bit 140 and the ring bit 150 and the water ejected from the nozzle 145 are taken into the space 101 from the slime intake port 146 and discharged from the slime discharge port 180. The

  Here, the outer casing 110 and the inner rod 120 are connected together by the drive transmission mechanism 10 so as to be rotatable together, so that the outer casing 110 rotates together with the inner rod 120 when drilling. As a result, the restraint from the ground or the bedrock to the outer casing 110 is relaxed, and the promotion of the drilling portion 100 is promoted.

  On the other hand, since the outer casing 110 and the inner rod 120 do not rotate relative to each other, slime is likely to accumulate in the space 101 and jamming is likely to occur compared to the case where they rotate relative to each other. Therefore, in order to suppress the occurrence of jamming due to the accumulation of slime in the space 101, the space 101 is cleaned when the drilling is stopped as shown in FIG.

  In cleaning the space 101, first, the inner rod connecting portion 24 and the inner rod 120 are retracted from the foremost position in the movable range by the slide driving device 230, and the tip portion 130A of the hydraulic hammer 130 is moved to the step portion 147 of the pilot bit 140. Separate from. Further, water is supplied from the cleaning swivel 160 to the hydraulic hammer 130.

  Here, since the clearance S is provided between the tip portion 130 </ b> A of the hydraulic hammer 130 and the stepped portion 147 of the pilot bit 140, water is sent from the clearance S to the space 101 and accumulated in the space 101. The slime is discharged from the slime discharge port 180 in a water stream.

  As described above, the double-pipe drilling machine 1 according to this embodiment includes the striking force applied to the pilot bit 140 by the hydraulic hammer 130 connected to the tip of the inner rod 120, the inner rod connecting portion 24, and the inner rod. The ground or rock is drilled using the rotational force applied to pilot bit 140 and ring bit 150 through 120 as a driving force. In this double pipe drilling machine 1, a space 101 serving as a slime discharge path is formed between the hydraulic hammer 130, the inner rod 120 and the inner rod connecting portion 24, and the outer casing 110 and the outer rod connecting portion 22. When the hydraulic hammer 130 is retracted relative to the pilot bit 140, water for cleaning the space 101 is interposed between the tip portion 130A of the hydraulic hammer 130 and the step portion 147 of the pilot bit 140. The gap S that flows out from the hydraulic hammer 130 into the space 101 is formed.

  The drive transmission mechanism 10 provided in the double-pipe drilling machine 1 configured as described above transmits a rotational force and a pressing force in the excavation direction from the drive unit 200 to the drilling unit 100. Here, the connecting portion 30 of the drive transmission mechanism 10 includes an inner rod connecting portion 24 connected to the rear end of the inner rod 120 and an outer rod connecting portion 22 connected to the rear end of the outer casing 110. These are connected so as to be rotatable integrally around the shaft center and relatively movable in the axial direction.

  That is, the drive transmission mechanism 10 integrates the inner rod connecting portion 24 connected to the rear end of the inner rod 120 and the outer rod connecting portion 22 connected to the rear end of the outer casing 110 into an inner rod connecting portion. By connecting only 24 to the rotational drive device 210, the transmission mechanism is simplified by using the rotational drive force as one system. Then, the hydraulic hammer 130 connected to the inner rod connecting portion 24 via the inner rod 120 is moved backward relative to the pilot bit 140 so that the tip portion 130A of the hydraulic hammer 130 and the step portion 147 of the pilot bit 140 A gap capable of flowing water is formed between the two, and the space 101 can be cleaned by flowing water from the gap into the space 101 serving as a slime discharge path.

  Therefore, according to the drive transmission mechanism 10 according to the present embodiment, the inner tube made of the inner rod 120 or the like and the outer tube made of the outer casing 110 or the like can be rotated with a simple configuration, and the inner tube can be rotated. Slime accumulation between the outer pipe and the outer pipe can be suppressed, and jamming in the double pipe drilling machine 1 can be suppressed.

  Further, the drive transmission mechanism 10 according to the present embodiment includes a flange 34 projecting radially outward from the inner rod connecting portion 24 at a position behind the outer rod connecting portion 22 in the inner rod connecting portion 24 in the digging direction, and a flange A flange 32 projecting radially outward from the outer rod connecting portion 22 at a position in front of the digging direction with respect to 34, and a penetration formed in the flange 32, supported by the flange 34 in parallel to the axis of the double pipe. And a shaft 38 slidably inserted into the hole. Here, when the relative rotation between the flange 32 and the flange 34 is stopped by the shaft 38, the outer rod connecting portion 22 and the inner rod connecting portion 24 become relatively unrotatable (can rotate together). On the other hand, since the flange 32 can move relative to the flange 34 along the shaft 38, the outer rod connecting portion 22 and the inner rod connecting portion 24 can move relative to each other in the axial direction.

  Further, in the drive transmission mechanism 10 according to the present embodiment, the flanges 32 and 34 are formed in a disk shape, and a plurality of shafts 38 are arranged around the double pipe at intervals, and these are formed into a disk-shaped flange. It is fixed to 34 and is inserted through the through hole of the disk-like flange 32. Thereby, the rotational force of the inner rod connecting portion 24 becomes the torque force amplified by the flange 34, and this torque force is transmitted to the outer rod connecting portion 22 and the outer rod 110 via the shaft 38 and the flange 32. The outer rod 110 can be rotated without being constrained by the ground.

  Further, the plate 36 is disposed so as to face the flange 34 protruding from the inner rod connecting portion 24 via the flange 32 protruding from the outer rod connecting portion 22 in the axial direction of the double pipe. A shaft 38 is fixed to the flange 34 at both ends. As a result, the shaft 38 can efficiently transmit the torque force amplified by the flange 34 to the flange 32 without being deformed by the torque force. Moreover, since the movable range in the axial direction of the double pipe of the flange 32 can be limited, the movable range in the axial direction of the inner rod connecting portion 24 and the outer rod connecting portion 22 can be limited. .

  In addition, the above-mentioned embodiment is for making an understanding of this invention easy, and does not limit this invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof. For example, in the above-described embodiment, the plate 36 is provided in the connecting portion 30, but this is not essential. When the plate 36 is not provided, it is indispensable to fix the shaft 38 to the flange 34 projecting from the inner rod connecting portion 24 and insert the shaft 38 through the through hole formed in the flange 32 projecting from the outer rod connecting portion 22. Alternatively, the shaft 38 may be fixed to the flange 32 and the shaft 38 may be inserted through a through hole formed in the flange 34.

  Further, it is not essential to form the connecting portion 30 by the flanges 32 and 34, the plate 36, and the shaft 38. For example, a key is formed on either the inner peripheral surface of the outer rod connecting portion 22 or the outer peripheral surface of the inner rod connecting portion 24 like the connecting portion between the tip of the hydraulic hammer 130 and the pilot bit 140 to connect the outer rod. A key groove that engages with the key is formed on either the inner peripheral surface of the portion 22 or the outer peripheral surface of the inner rod connecting portion 24, and the inner tube 22 and the outer tube 24 are formed by the key and the key groove. You may connect so that relative rotation is impossible and relative movement is possible in these axial directions.

DESCRIPTION OF SYMBOLS 1 Double pipe drilling machine, 10 Drive transmission mechanism, 20 Double pipe connection part, 22 Outer rod connection part, 24 Inner rod connection part, 30 Connection part, 32 Flange (2nd member), 34 Flange (1st member) ), 36 plate (third member), 38 shaft (shaft member), 100 drilling portion, 101 space (discharge passage), 110 outer casing (outer tube), 120 inner rod (inner tube), 130 hydraulic hammer, 130A Tip, 140 Pilot bit (bit part), 142 bit, 143 Key groove, 144 key, 145 nozzle, 146 Slime intake, 147 Stepped part, 150 Ring bit, 152 bit, 160 Cleaning swivel, 170 High pressure swivel, 180 Slime discharge port, 200 drive unit (drive device), 210 Rotation drive device , 220 guide 230 slide drive unit

Claims (5)

A striking force given to the bit part by a hydraulic hammer connected to the inner pipe of the double pipe and a rotational force given to the bit part via the inner pipe are propulsive forces, and the outer pipe and the double pipe When a slime discharge path is formed between the pipe and the hydraulic hammer is retracted relative to the bit part, water for cleaning the discharge path is provided between the hydraulic hammer and the bit part. Is provided in a double pipe drilling machine configured to create a gap that flows out from the hydraulic hammer to the discharge path, and a rotational force and a direction of digging are applied to the double pipe from a drive unit of the double pipe drilling machine. A drive transmission mechanism for transmitting a pressing force to
A drive transmission mechanism for a double-pipe drilling machine, wherein the inner pipe and the outer pipe are connected so as to be integrally rotatable and relatively movable in their axial directions. A first member projecting radially outward from the inner pipe at a position behind the outer pipe in the digging direction in the inner pipe;
A second member projecting radially outward from the outer pipe at a position on the front side in the digging direction from the first member;
A through hole formed in one of the first member and the second member and supported in parallel to the axis of the double tube and formed in the other of the first member and the second member. The drive transmission mechanism for a double-pipe drilling machine according to claim 1, further comprising: a shaft member that is slidably inserted. The first member and the second member are flanges formed in an annular shape,
The drive transmission mechanism for a double-pipe drilling machine according to claim 2, wherein the plurality of shaft members are arranged around the double-pipe at intervals. The shaft member has one end fixed to the first member, and is slidably inserted into the through hole formed in the second member.
The second member is provided so as to face the first member via the second member in the axial direction of the double pipe, and includes a third member to which the other end of the shaft member is fixed. Or the drive transmission mechanism of the double pipe drilling machine of Claim 3. A striking force given to the bit part by a hydraulic hammer connected to the inner pipe of the double pipe and a rotational force given to the bit part via the inner pipe are propulsive forces, and the outer pipe and the double pipe When a slime discharge path is formed between the pipe and the hydraulic hammer is retracted relative to the bit part, water for cleaning the discharge path is provided between the hydraulic hammer and the bit part. Is configured so that a gap flows out from the hydraulic hammer to the discharge path,
A double pipe drilling machine comprising a drive transmission mechanism that transmits a rotational force and a pressing force in the direction of excavation from the drive device to the double pipe,
The drive transmission mechanism is a double-pipe drilling machine characterized in that the inner tube and the outer tube are connected so as to be rotatable integrally and relatively movable in the axial direction.

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