JP2022051878A - Drill machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a drill machine due to falling rock during drilling.

SOLUTION: A tip fixture jig 4b that is installed at a tip of a guide cell 4 guiding a movement of a drill unit 5 to a drilling direction and fixes the guide cell 4 to a drill surface includes a pad portion 10 including a pad 10a that can elastically deform by pressing to a drill surface and a holding portion 10b that holds a back surface of the pad 10a, a guide portion 11 that is provided behind the pad portion 10 and guides an advance/retreat movement of the pad 10a, a housing portion 13 that is supposed by a support body 4a provided to the guide cell 4 and is positioned behind the guide portion 10, a pad pressing apparatus 12 that includes a piston sliding in a cylinder tube 12b by the cylinder tube 12b and hydraulic and housed in the housing portion 13, and a supply and exhaust port 12c that is provided in the cylinder tube 12b, is housed in the housing portion 13, and whose conduit of hydraulic that is disposed in the housing portion 13 and the support body 4a and drives the pad pressing apparatus 12.

SELECTED DRAWING: Figure 5

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a drilling machine, and is applied to, for example, a drilling machine for drilling a hole for blasting (hereinafter referred to as “blasting hole”) for loading explosives into rock or the like in tunnel excavation work by a blasting method. It is about effective technology.

In tunnel excavation work by the blasting method, after blasting holes are drilled in multiple places of the rock to be excavated by a drilling machine, explosives are set in each blasting hole and the rock is excavated by blasting. There is. When drilling a blasting hole, the tip of the guide cell of the drilling machine is pressed against the bedrock and fixed, and then the drilling bit at the tip of the drilling rod installed in a movable state on the guide cell is rotated. The blasting hole is drilled by pressing it against the bedrock.

As for this type of drilling machine, for example, the one described in Patent Document 1 is known.

The drilling machine described in Patent Document 1 is provided with a fixing jig for fixing the tip of a guide cell which is a member for guiding the drilling unit in the front-rear direction. The fixing jig has a claw body portion at the tip thereof, which is a steel claw type, and has a structure connected to a claw body pressing device composed of a hydraulic cylinder via a ball seat portion. In addition, the telescopic support rod holds the posture of the fixing jig, and the linear guide ensures the straightness of movement of the fixing jig when the claw body pressing device is extended.

Further, according to the drilling machine described in Patent Document 1, since the fixing jig does not separate from the bedrock, the binding force at the tip of the guide cell can be maintained and the accuracy of the drilling position is improved.

Japanese Unexamined Patent Publication No. 2017-31744

Here, if the bedrock falls and directly hits a portion vulnerable to the impact of the drilling machine when drilling the blasting hole, the drilling machine may be damaged and the drilling may not be possible.

The present invention has been made from the above-mentioned technical background, and an object of the present invention is to provide a technique capable of preventing damage to a drilling machine due to a rock fall during drilling.

In order to solve the above problems, the drilling machine of the present invention according to claim 1 supports the drilling means for forming a hole and the drilling means, and moves the drilling means in the drilling direction. To guide the guide means, a fixing jig installed at the tip of the guide means to fix the guide means to the drilling surface, and to support the guide means in a driveable state and to move in the site. The fixing jig has a vehicle body provided with a moving means of the above, and the fixing jig includes a pad that is elastically deformable by being pressed against the drilling surface, a pad portion that holds a holding portion that holds the back surface of the pad, and the pad portion. A casing provided behind the pad portion to guide the pad to move forward and backward while facing the front, and a casing supported by a support provided in the guide means and located behind the guide portion. A body portion, a cylinder tube, and a pressing means that includes a cylinder tube and a piston that slides in the cylinder tube by hydraulic pressure and is housed in the housing portion and presses the pad against the drilling surface via the guide portion, and the cylinder. It is provided with a supply / discharge port provided in the tube, housed in the housing portion, arranged in the housing portion and in the support body, and connected with a hydraulic pipeline for driving the pressing means. The guide portion has a liner fixed to the housing portion accommodating the pressing means, and a tip portion fixed to the position of the back center portion of the pad in the holding portion, and a rear end portion attached to the piston. The main body is fixed to a plunger that appears and disappears from the cylinder tube and slides in the liner due to the appearance of the plunger, and the main body guides the advancing and retreating movement of the pad.

According to the present invention, since the pressing means and the supply / discharge port are housed in the housing portion and the pipeline is arranged in the housing portion and in the support body, the portion vulnerable to the impact of the drilling machine is the housing portion and the portion. It will be protected by a support. This makes it possible to prevent damage to the drilling machine due to falling rock during drilling.

It is a side view of the drilling machine which concerns on one Embodiment of this invention. It is a top view of the drilling machine of FIG. It is a front view of the drilling machine of FIG. 1 at the time of drilling. It is an enlarged side view of the guide cell and the drilling unit of the drilling machine of FIG. It is sectional drawing of the main part of a fixing jig. (A) is a cross-sectional view of a main part of the fixing jig in a contracted state, and (b) is a cross-sectional view of a main part of the fixing jig in an extended state. It is a schematic block diagram of the hydraulic system of the drilling machine of FIG. (A) is a cross-sectional view of the tunnel during the excavation process as viewed from above, and (b) is a cross-sectional view of the tunnel of FIG. 8 (a) as viewed from the side. (A) and (b) are explanatory views of the drilling machine in the blasting hole forming process. It is an output waveform diagram of the hydraulic system of the excavator in the blasting hole forming process. (A) and (b) are cross-sectional views of the tunnel during the excavation process following FIG. 8 as viewed from the side.

Hereinafter, embodiments as an example of the present invention will be described in detail with reference to the drawings. In addition, in the drawing for demonstrating the embodiment, the same components are in principle the same reference numerals, and the repeated description thereof will be omitted.

First, the overall configuration of the drilling machine of the present embodiment will be described with reference to FIGS. 1 to 4. 1 is a side view of a drilling machine according to an embodiment of the present invention, FIG. 2 is a plan view of the drilling machine of FIG. 1, and FIG. 3 is a front view of the drilling machine of FIG. 1 at the time of drilling. 4 is an enlarged side view of the guide cell and the drilling unit of the drilling machine of FIG. 1.

The drilling machine 1 of the present embodiment is, for example, a device for drilling a blasting hole for loading explosives into a bedrock or the like in a tunnel excavation work by a blasting method, and is a device for drilling a blasting hole, a vehicle body 2, a boom 3, and a guide. It includes a cell (guidance means) 4, a drilling unit (drilling means) 5, and a cage 6. Although not particularly limited, as the drilling machine 1, for example, JTH2RS-190EX (2 booms, 2 cages) of Furukawa Rock Drill is used. However, here, as an example, since the drilling length of the blasting hole is 4 m, the feed length of the guide cell 4 of the drilling machine 1 is set to 4040 mm.

The vehicle body 2 of the drilling machine 1 is composed of, for example, a four-wheel drive vehicle having four wheels (moving means) 2a. This makes it possible for the drilling machine 1 to freely move around the work site (inside the site). Further, two elevating jacks 2b (four in total) are installed in front of the front wheels and behind the rear wheels of the vehicle body 2. As shown in FIG. 3, the drilling machine 1 is fixed to the ground G in a state where the wheels 2a are lifted to a position away from the ground by the elevating jack 2b during the drilling operation. However, the vehicle body 2 is not limited to the four-wheel drive type vehicle, and for example, a caterpillar type vehicle may be used.

For example, two booms 3 are mechanically connected to the front portion of the vehicle body 2 (the portion in the forward direction of the drilling machine 1) so as to be movable in the vertical and horizontal directions. The boom 3 is a mechanism that supports the guide cell 4 and changes the vertical and horizontal angles of the guide cell 4.

The guide cell 4 supported by the boom 3 is a member that guides the drilling unit 5 in the front-rear direction, and includes a support 4a, a tip fixing jig (hereinafter referred to as a fixing jig) 4b, and a cell pressing device 4c. It is equipped with.

The fixing jig 4b is a device that makes it possible to press the tip of the guide cell 4 against a drilling surface such as a bedrock to fix it even when the feed pressure is applied (during drilling), and the tip of the support 4a. It is attached to. Here, the case where the fixing jig 4b is attached to each of the tips of the two guide cells 4 has been described, but the fixing jig may be attached only to the tips of one guide cell 4. The configuration of the fixing jig 4b will be described in detail later.

The cell pressing device 4c is a pressing means for pressing and fixing the tip of the guide cell 4 (that is, the fixing jig 4b) to the drilling surface of rock or the like before the feed pressure action, and is attached to the lower part of the support 4a. .. The cell pressing device 4c is composed of, for example, a hydraulic jack, and is mechanically connected to a hydraulic unit (not shown in FIGS. 1 to 4) installed in the vehicle body 2. This hydraulic unit will be described in detail later with reference to FIG. 7.

As described above, the drilling unit 5 is supported in the guide cell 4 in a state where it can move in the front-rear direction. The drilling unit 5 is a drilling means for drilling a blasting hole in a bedrock or the like, and a drifter 5a, a drilling rod 5b, and a drilling bit 5c are machined in order along a direction away from the vehicle body 2. It is prepared in a state where it is connected in series.

The drifter 5a is a hydraulic drive means, and is capable of applying a rotational force and a striking force to the drilling rod 5b and the drilling bit 5c and reciprocating along the guide cell 4. The rotational force of the drifter 5a is given by the built-in motor, and the striking force is given by the built-in piston. Further, the feed pressure (pressure for pressing the drilling bit 5c against the bedrock) is applied by the forward movement of the drifter 5a. The hydraulic device for reciprocating the drifter 5a is, for example, a hydraulic cylinder or the like, and is mechanically connected to a hydraulic unit (not shown in FIGS. 1 to 4) that supplies hydraulic pressure to the cell pressing device 4c of the guide cell 4. Has been done. Although not particularly limited, HD190 is used as the drifter 5a, for example. Further, the feed pressure of the drifter 5a is based on, for example, 10 to 12 MPa, which is considered to be the maximum level in CI-class rock mass.

The drilling rod 5b is a member that transmits the rotational force and pressing force from the drifter 5a to the drilling bit 5c. For example, a 32 hexagonal rod that is commonly used in the field is used. The drilling bit 5c is a member that is pressed against a bedrock or the like in a rotated state to excavate the bedrock or the like, and for example, a φ45 button bit that is commonly used in the field is used.

Next, a configuration example of the fixing jig 4b described above will be described with reference to FIGS. 5 and 6. Here, FIG. 5 is a cross-sectional view of a main part of the fixing jig, and FIG. 6 is a cross-sectional view showing an extension operation of the fixing jig.

The fixing jig 4b includes a pad portion 10, a guide portion 11, a pad pressing device (pressing means) 12, and a housing portion 13 that are mutually unitized.

The pad portion 10 includes a pad 10a and a holding portion 10b for holding the pad 10a.

The pad 10a is a member that is in contact with the excavated surface of the bedrock at the time of drilling and transmits a pressing force (pressing load) to the bedrock. For the pad 10a, a general rubber hood pad attached to the tip of the guide cell of the drilling machine is used, and the pad 10a is pressed against the drilling surface to enable elastic deformation. In the present embodiment, the outer circumference of the hood pad is chamfered to reduce the area of the tip to reduce the influence of the eccentric load when it comes into contact with the drilled surface of the bedrock. As long as the pad 10a is elastically deformable, various members can be applied, and the pad 10a is not limited to the one shown in the present embodiment.

The holding portion 10b is a metal member that holds the pad 10a so as to surround the outer periphery of the rear portion of the pad 10a, and a substantially cylindrical sleeve 10c is attached to the back surface. The sleeve 10c will be described later.

The guide portion 11 is provided behind the pad portion 10 and is a member that guides the pad 10a to move forward and backward while facing the front. The liner 11a fixed to the housing portion 13 and this liner It is provided with a main body portion 11b that slides in 11a. The tip of the main body 11b is fixed to the holding portion 10b, the rear end is fixed to the plunger 12a (described later) of the pad pressing device 12, and the pad slides in the liner 11a due to the appearance of the plunger 12a. Move the part 10 forward and backward.

The pad pressing device 12 is a pressing means for keeping the load that the fixing jig 4b presses against the bedrock always constant even when the feed pressure is applied (during drilling), and is housed in the housing portion 13. It is provided. The pad pressing device 12 is composed of, for example, a hydraulic cylinder, and has a piston (not shown) that slides in the cylinder tube 12b by hydraulic pressure and the above-mentioned plunger 12a that is attached to the piston and appears and disappears from the cylinder tube 12b. I have.

Therefore, in addition to the pad pressing device 12 described above, the housing portion 13 also houses a supply / discharge port 12c for supplying / discharging pressure oil to the pad pressing device 12. The pipeline from the supply / discharge port 12c to the accumulator AC (described later) for driving the pad pressing device 12 is arranged in the housing portion 13 and the support 4a to be protected from external impact.

Further, as shown in the figure, the housing portion 13 is attached to the tip of the support 4a via the mounting plate (mounting member) 14. That is, as described above, since the pad portion 10, the guide portion 11, the pad pressing device 12, and the housing portion 13 are unitized with each other to form the fixing jig 4b, the fixing jig 4b is a mounting plate. It is installed at the tip of the guide cell 4 via 14.

By accommodating the pad pressing device 12 and the supply / discharge port 12c in the housing portion 13 in this way, even if the bedrock falls during excavation, the pad pressing device 12 and the supply / discharge device 12 which are vulnerable to impact are supplied. Since the exhaust port 12c is protected by the housing portion 13, the occurrence of defects is prevented.

Further, since the pad portion 10, the guide portion 11, the pad pressing device 12, and the housing portion 13 are unitized with each other to form the fixing jig 4b, the fixing jig 4b can be used as a guide cell only by using the mounting plate 14. It can be easily installed at the tip of 4.

As described above, the tip end portion of the plunger 12a of the pad pressing device 12 is fixed to the rear end portion of the main body portion 11b constituting the guide portion 11. In the pad pressing device 12, the maximum load is, for example, 50 kN, and the stroke of the plunger 12a is, for example, 50 mm. The pad pressing device 12 is operated by an accumulator AC which is a pressure accumulator means, and constitutes a part of a hydraulic unit for setting a feed pressure of the cell pressing device 4c and the drifter 5a described above.

Then, when the pad portion 10 pressed against the excavation surface and in the retracted position as shown in FIG. 6A weakens the pressing force against the excavation surface and the pressure in the cylinder tube 12b decreases, the accumulator AC is used with the hydraulic fluid. The piston slides so that a certain oil is supplied and the plunger 12a is projected. As a result, as shown in FIG. 6B, the main body portion 11b of the guide portion 11 slides in the liner 11a, and the sleeve 10c attached to the back surface of the holding portion 10b slides on the outer periphery of the liner 11a. Then, the pad portion 10 moves forward.

The sleeve 10c may not always be provided. However, although the liner 11a and the main body portion 11b can also structurally strengthen the advancing / retreating mechanism of the pad portion 10, if the sleeve 10c is provided, the pad portion 10 can be further strengthened.

Next, the hydraulic system constituting the drilling machine 1 of the present embodiment will be described with reference to FIG. 7. FIG. 7 is a schematic configuration diagram of the hydraulic system of the drilling machine of FIG.

As shown in FIG. 7, the drilling machine 1 of the present embodiment has a hydraulic unit (pressure generating means) U and a control unit C. The hydraulic unit U is a hydraulic unit that drives a cell pressing device 4c for a guide cell, a hydraulic device 5d for reciprocating a drifter 5a for feed pressure, and a pad pressing device 12 for a fixing jig 4b. Further, the control unit C is a device that electrically controls the drilling machine 1.

Here, the hydraulic unit U includes an engine (driving means) E, a hydraulic pump (hydraulic supply means) P, a valve (switching means) V, and an accumulator (accumulation means) AC.

The engine E is a device for driving the wheels 2a of the drilling machine 1, and is provided in the vehicle body 2. The hydraulic pump P is operated by driving the engine E.

The hydraulic pump P is a device that, when operated by the engine E, sucks hydraulic oil from a hydraulic tank (not shown) to generate pressure oil. The hydraulic pump P is connected to the cell pressing device 4c and the hydraulic device 5d via the valve V, and is also connected to the accumulator AC and the pad pressing device 12.

The valve V is a direction switching valve that supplies the pressure oil generated by the hydraulic pump P to either the cell pressing device 4c or the hydraulic device 5d. The switching operation of the valve V is controlled by the control unit C.

Further, as described above, the accumulator AC operates the pad pressing device 12 by receiving the supply of the pressure oil generated by the hydraulic pump P.

As described above, in the present embodiment, the pressure oil is supplied from the hydraulic pump P to the cell pressing device 4c and the hydraulic device 5d to directly operate the accumulator AC, and the pressure oil is supplied from the hydraulic pump P to the accumulator AC to operate the accumulator AC. The pad pressing device 12 is indirectly operated via the above. As a result, the proper working pressure for the cell pressing device 4c and the hydraulic device 5d and the proper working pressure for the pad pressing device 12 (cell pressing device 4c) by a single hydraulic unit U, that is, without providing a plurality of hydraulic units. And the working pressure is different from that of the hydraulic device 5d), so that the hydraulic circuit can be simplified.

Next, an example of a tunnel excavation method by the blasting method will be described with reference to FIGS. 8 to 11. 8 (a) is a cross-sectional view of the tunnel during the excavation process as viewed from above, FIG. 8 (b) is a cross-sectional view of the tunnel of FIG. 8 (a) as viewed from the side, and FIGS. 9 (a) and 9 (b) are. Explanatory drawing of the drilling machine during the blasting hole forming process, FIG. 10 is an output waveform diagram of the hydraulic system of the excavator in the blasting hole forming process, and FIGS. 11 (a) and 11 (b) are tunnels during the excavation process following FIG. It is a cross-sectional view seen from the side. In FIG. 10, reference numeral t1 is a time when the action of the feed pressure starts (drilling start). Further, reference numeral W1 is an output waveform of the cell pressing device 4c of the guide cell 4, reference numeral W2 is an output waveform of the hydraulic device 5d, and reference numeral W3 is an output waveform of the pad pressing device 12.

First, as shown in FIG. 8, after the drilling machine 1 is run close to the bedrock S of the face in the tunnel T, the elevating jack 2b of the drilling machine 1 is extended to fix the drilling machine 1. Subsequently, the guide cell 4 is moved to a predetermined position by adjusting the angle and elongation of the boom 3 of the drilling machine 1.

Next, as shown in the waveform W1 of FIG. 9A and FIG. 10, the cell pressing device 4c is pressed by supplying pressure oil from the hydraulic unit U of the drilling machine 1 to the cell pressing device 4c at the lower part of the guide cell 4. It is extended and the fixing jig 4b at the tip of the guide cell 4 is pressed against the bedrock S of the face. That is, as shown in FIG. 9A, the pad 10a provided on the fixing jig 4b at the tip of the guide cell 4 is pressed against the bedrock S by the pressure F1 from the cell pressing device 4c, and the shape of the bedrock S is formed. It is elastically deformed along and fixed. At this time, the pressure of the cell pressing device 4c is increased to, for example, 20 MPa (maximum value of the drilling machine 1).

Subsequently, as shown in the waveforms W1 and W2 at time t1 in FIGS. 9 (b) and 10, the hydraulic circuit from the hydraulic unit U to the cell pressing device 4c is closed (valve V) for drilling the rupture hole. Closes the supply of pressure oil to the cell pressing device 4c) and opens the hydraulic circuit from the hydraulic unit U to the hydraulic device 5d (supplies the pressure oil to the hydraulic device 5d by the valve V) to open the drilling bit 5c. A rupture hole H is drilled in the bedrock S by pressing it against the bedrock S with a predetermined feed pressure.

Here, when the supply of hydraulic pressure to the cell pressing device 4c is closed, the hydraulic pressure drops to about 2 MPa, so that the tip of the guide cell 4 is separated from the bedrock S and the binding force is lost, so that the drilling bit 5c is located at the drilling position. As a result of the guide cell 4 moving left and right or up and down in the restrained state, the drilling rod 5b supporting the drilling bit 5c bends, and the drilling position of the blasting hole deviates from the target position.

When the binding force at the tip of the guide cell 4 by the cell pressing device 4c is lost in this way, in the present embodiment, the pressing force on the bedrock S in the pad portion 10 is weakened and the pressure in the cylinder tube 12b is reduced. Then, as shown in FIG. 9B and the waveform W3 at time t1 in FIG. 10, pressure oil is supplied from the accumulator AC to the pad pressing device 12 of the fixing jig 4b, and the hydraulic pressure of the pad pressing device 12 is, for example. The increase to 20 MPa causes the piston to slide, the plunger 12a to protrude, the pad portion 10 to move forward, and the pad 10a to be pressed against the bedrock S of the face.

That is, as shown in FIG. 9B, the pad 10a provided on the fixing jig 4b at the tip of the guide cell 4 is pressed against the bedrock S by the pressure F2 from the pad pressing device 12 of the fixing jig 4b. It is elastically deformed and fixed along the shape of the bedrock S. As a result, the position of the fixing jig 4b of the guide cell 4 can be fixed at the time of drilling, so that the displacement of the guide cell 4 at the time of drilling can be suppressed or prevented. Therefore, the accuracy of the drilling position of the blasting hole can be improved.

Then, in the present embodiment, as a fixing jig 4b for fixing the guide cell 4 to the drilling surface, a pad that is pressed against the bedrock S (drilling surface) and elastically deforms to alleviate the impact at the time of drilling. A pad portion 10 having a 10a is provided, and the pad portion 10 is directly connected to the pad pressing device 12 via a guide portion 11. Therefore, the strength of the fixing jig 4b can be improved, and even when the pressed rock or the like is hard, the risk of damage to the fixing jig 4b due to insufficient strength is reduced.

If the feed pressure of the drilling bit 5c is increased for drilling the blasting hole, the guide cell 4 may move backward and the pressing force of the pad pressing device 12 of the fixing jig 4b may decrease. Even in that case, pressure oil is instantly sent from the accumulator AC to the pad pressing device 12 of the fixing jig 4b, and the stroke of the plunger 12a of the pad pressing device 12 is extended to maintain the fixed state of the tip of the guide cell 4. can do.

By the way, after drilling a blasting hole H in the bedrock S in this way, an explosive is set in the blasting hole H, and then the explosive is blown up as shown in FIG. As shown in b), the tunnel T is excavated. At this time, according to the present embodiment, since the drilling position accuracy of the blasting hole can be improved, stable blasting can be realized even for long hole blasting where it is difficult to secure the drilling position accuracy. .. Therefore, for example, the tunnel T can be efficiently excavated even in a hard rock equivalent to the B to CI class, so that the excavation period of the tunnel T can be shortened.

Although the invention made by the present inventor has been specifically described above based on the embodiments, the embodiments disclosed in the present specification are exemplary in all respects and are limited to the disclosed technology. It's not a thing. That is, the technical scope of the present invention is not limitedly interpreted based on the description in the above-described embodiment, but should be interpreted in accordance with the description of the scope of claims, and the scope of claims. All changes are included as long as they do not deviate from the stated technology and the equivalent technology and the gist of the claims.

For example, in the above-described embodiment, the case where a two-boom, two-cage drilling machine is used has been described, but the number of booms and the number of cages are not limited to this, and can be variously changed.

As described above, in the above-described embodiment, the case where the drilling machine according to the present invention is applied to the drilling machine for blasting holes has been described, but the present invention is not limited to this, and various applications are possible. For example, it can be applied to a drilling machine for drilling holes for anchoring.

1 Drilling machine 2 Vehicle body 3 Boom 4 Guide cell (guidance means)
4a Support 4b Tip fixing jig (fixing jig)
4c Cell pressing device 5 Drilling unit (drilling means)
5a Drifter 5b Drilling rod 5c Drilling bit 6 Cage 10 Pad 10a Pad 10b Holding 10c Sleeve 11 Guide 11a Liner 11b Main body 12 Pad pressing device (pressing means)
12a Plunger 12b Cylinder tube 12c Supply / discharge port 13 Housing unit 14 Mounting plate (mounting member)
AC accumulator (accumulation means)
C Control unit E Engine G Earth H Blasting hole P Hydraulic pump S Bedrock U Hydraulic unit

Claims (1)

Drilling means to form holes and
A guide means that supports the drilling means and guides the movement of the drilling means in the drilling direction.
A fixing jig installed at the tip of the guide means and fixing the guide means to the drilling surface,
It has a vehicle body that supports the guiding means in a driveable state and is provided with a moving means for moving within the site.
The fixing jig is
A pad that can be elastically deformed by being pressed against the drilled surface, a pad portion having a holding portion that holds the back surface of the pad, and a pad portion.
A guide portion provided behind the pad portion to guide the pad to move forward and backward while facing the front, and a guide portion.
A housing portion supported by a support provided in the guide means and located behind the guide portion, and a housing portion.
A pressing means that includes a cylinder tube and a piston that slides in the cylinder tube by hydraulic pressure and is housed in the housing portion, and presses the pad against the drilled surface via the guide portion.
It is provided with a supply / discharge port provided in the cylinder tube, housed in the housing portion, arranged in the housing portion and in the support body, and connected with a hydraulic pipeline for driving the pressing means. ,
The guide portion has a liner fixed to the housing portion accommodating the pressing means, and a tip portion thereof is fixed to a position at the center of the back surface of the pad in the holding portion, and a rear end portion is attached to the piston. A main body portion that is fixed to a plunger that appears and disappears from the cylinder tube and slides in the liner due to the appearance and appearance of the plunger is provided, and the main body portion guides the advance / retreat movement of the pad.
A drilling machine characterized by that.

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