Wet piercing tools

Abstract

To provide a wet type drilling tool having a structure capable of adjusting the depth in drilling and securely suppressing the stains of a drilling part.SOLUTION: A wet type drilling tool comprises a shaft 20 displaceably forming a water storage holder 16 having a coolant circulation region accompanying a movable pipe 18, allowing the tip part of a wet type core bit 12 to project from the water storage holder 16 to the direction of the part to be drilled and further controlling the projection quantity thereof in accordance with a stress from the part to be drilled. The shaft 20 is stored in a shaft storage body 30 provided with a spring at the inside accompanying the movable pipe 18 shrunk when the projection quantity of the wet type core bit 12 from the water storage holder 16 increases and energizes the tip part of the wet type core bit 12 to the direction of the part to be drilled upon the start of drilling or during drilling.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wet drilling tool used for interior construction work of buildings and the like. [Background technology]

[0002] A known example of this type of wet drilling tool is the wet power drill disclosed in Patent Document 1. This wet power drill is a tool that drills holes by dripping water from a water injection set, and the outer periphery of the drilling blade is a cone shape that widens from the power source toward the drilling surface. With this wet power drill, cutting water does not splash around the periphery after drilling, nor does it infiltrate into the power drill.

[0003] Also available on the market are handheld electric drills and associated vacuum sets that supply cooling water via a water supply tube to a wet-use shank fitted with a diamond bit, suck up the cooling water along with dust generated during drilling through a ring-shaped suction pad connected to a vacuum device, and then drain the water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-256063 Summary of the Invention [Problem to be solved by the invention]

[0005] The wet-type electric drill disclosed in Patent Document 1 and commercially available handheld wet-type drills have a fixed core bit length and no depth adjustment mechanism, making it difficult to increase or adjust the drilling depth. Furthermore, after activating the vacuum switch, the water supply device and wet drill must be activated. After drilling, the water supply device and wet drill must be stopped, and then the vacuum switch must be turned off. If the order of operations is incorrect or the vacuum switch is accidentally touched and the vacuum switch is turned off unintentionally, the surrounding area can be contaminated with wastewater containing drilling waste. In particular, when the finished surface is porous, such as ceramic tile or lysine finish, cleaning the soiled areas that come into contact with wastewater is extremely difficult. Therefore, there is a need to more reliably prevent the vacuum switch from being turned off or the water supply device from being turned on due to human error or other malfunctions.

[0006] A main object of the present invention is to provide a wet drilling tool having a structure that can increase the drilling depth while reliably suppressing contamination of the drilled area. Other objects of the present invention will become apparent from the embodiments described below. [Means for solving the problem]

[0007] A wet drilling tool according to one embodiment of the present invention includes a refrigerant circulation mechanism that forms a displaceable refrigerant circulation area that includes the outer surface of the wet core bit and the drilled portion to be drilled by the wet core bit, and that circulates a predetermined refrigerant in the refrigerant circulation area; a tip of the wet core bit protrudes from the refrigerant circulation area toward the drilled portion, and at the start of drilling or during drilling, a refrigerant circulation mechanism that urges the refrigerant circulation area in the direction of the refrigerant circulation area at a location away from a tube that forms a drainage path for the refrigerant circulating in the refrigerant circulation area. The drilling depth of the drilled portion is controlled through the shaft. and a control mechanism. [Effects of the Invention]

[0008] According to the wet drilling tool of the present invention, it is possible to reliably prevent contamination of the drilled area while increasing the drilling depth. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an example of the structure of a wet-type power drill according to an embodiment of the present invention; [Figure 2] (a) is a front view of a wet electric drill, (b) is a right side view, (c) is a left side view, (d) is a back view, and (e) is a top view. [Figure 3] Exploded view of the water supply and drainage control mechanism. [Figure 4] FIG. [Figure 5] 1A is a cross-sectional view showing an example of the structure of a shaft accommodating body, and FIG. 1B is an enlarged view of the part circled in FIG. 1A. [Figure 6] A side view of a wet power drill with the wet core bit removed. [Figure 7] FIG. 10 is a side view showing the state of the wet-type power drill when attempting to attach a wet-type core bit. [Figure 8] Front view of the water supply shank. [Figure 9] FIG. 1 is a side view of a water supply shank. [Figure 10] HH cross section of Figure 9. [Figure 11] FIG. 2 is a side view showing the initial state of the wet-type power drill. [Figure 12] FIG. 10 is a diagram showing the relative positional relationship between the detection metal plate and the proximity sensor in the initial state. [Figure 13] FIG. 10 is a side view of the wet power drill when it starts cutting. [Figure 14] 15 is a diagram showing the relative positional relationship between the detection metal plate and the proximity sensor in the state shown in FIG. 14. [Figure 15] FIG. 2 is a side view of the wet-type power drill showing the movable tube and shaft in their most retracted state. [Figure 16] 15 is a diagram showing the relative positional relationship between the detection metal plate and the proximity sensor in the state shown in FIG. 14. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment in which the present invention is applied to a handheld wet-type power drill will be described below. The wet-type power drill of this embodiment can be realized by adding a water supply and drainage control mechanism for supplying and discharging a coolant to a commercially available dry-type power drill. The coolant may be a semi-liquid such as compressed air or gel. However, for versatility, this specification describes an example in which cooling water supplied from a water supply device, such as tap water, is used as the coolant, and a known vacuum device is used to discharge wastewater mixed with the cooling water and shavings. The water supply device and vacuum device each operate when the power is turned on and stop operating when the power is turned off. However, if the power is turned on and off in the wrong order, problems such as water leakage can occur. Therefore, this embodiment is designed to avoid such situations.

[0011] For ease of explanation, the drawings accompanying this specification use orthogonal three-dimensional axes X, Y, and Z. The Z axis represents the vertical height direction of the wet-type power drill, the X axis represents the front-to-back direction, and the Y axis represents the width direction. Also, viewing a wet-type power drill or the like from the Z axis direction (above) may be referred to as a plan view or top view, viewing from in front of the X axis as a front view, viewing from behind the X axis as a rear view, viewing from the left lateral side of the Y axis as a left side view, and viewing from the right lateral side of the Y axis as a right side view.

[0012] FIG. 1 is a perspective view showing an example of the structure of a wet-type power drill 1 according to this embodiment. FIG. 2(a) is a front view of the wet-type power drill 1, FIG. 2(b) is a right side view, FIG. 2(c) is a left side view, FIG. 2(d) is a rear view, and FIG. 2(e) is a top view. The wet-type power drill 1 can be configured, for example, by adding a water supply and drainage control mechanism to a commercially available power drill 100 having a spindle and a spindle rotation drive mechanism. The power drill 100 has a housing of a predetermined shape, and accommodates an electric motor for applying rotational drive force to the spindle and its control device. In addition, a handle 101, an operation switch 102, a battery 103, and the like, which are used by the operator when working, are provided on the outer surface of the housing.

[0013] The water supply and drainage control mechanism includes a water supply shank 11, a wet core bit 12, a pipe mounting holder 13, a fixed pipe 15, a water storage holder 16, a movable pipe 18, a shaft 20, a shaft holder 30, and a switch box 40 for preventing malfunctions. A drainage hose 80 connected to a vacuum device (not shown) is fixed to the end of the fixed pipe 15 in the -X direction.

[0014] The water supply shank 11 includes a shank body 111, a drain 112 fixed to a lateral side of the shank body 111, and an opening / closing lever 113. The shank body 111 is a molded product made of a hard material, such as stainless steel, and has a water storage space formed therein to which cooling water is supplied. The shank body 111 also has a pair of opposing surfaces in the water storage space. The spindle of the power drill 100 is fixed to one surface, and the wet core bit 12 is fixed to the other surface. The shank body 111 not only supplies cooling water, but also aligns the axes of the motor, spindle, and wet core bit 12 of the power drill 100 during operation, thereby reducing axial wobble during rotation. The structure for this purpose will be described in detail later. The wet core bit 12 can be, for example, a diamond bit, but in this embodiment, its base end is molded into a shape corresponding to the structure of the water supply shank 11. These structures will also be described later.

[0015] A water supply hose connected to a water supply device (not shown) is attached to the drain 112 of the water supply shank 11. The water supply hose itself is made of a flexible material, but its attachment to the drain 112 is watertightly connected using an attachment or the like. The opening / closing lever 113 is an adjustment member for the internal valve that mechanically opens and closes the water supply passage from the water supply hose to the shank body 111. By rotating the opening / closing lever 113, for example, parallel to the Z direction, the operator maximizes the opening area of ​​the internal valve, and by rotating it parallel to the X direction, the opening area of ​​the internal valve is minimized. In other words, by rotating the opening / closing lever 113 of the drain 112, the amount of cooling water supplied per unit time to the water storage space and the water pressure can be finely adjusted.

[0016] The wet core bit 12 is a hard tool component with a water supply passage formed inside or on the side leading to the tip. The base end of the wet core bit 12 has a shape and structure that matches the fixing structure of the water supply shank 11 to which it is fixed. In this embodiment, an example is shown in which a screw is threaded to match the fixing structure of the shank body 111 of the water supply shank 11. The tip of the wet core bit 12 is molded into a shape and size designed according to the drilling (boring) diameter. Furthermore, the wet core bit 12 is removably fixed to the shank body 111 of the water supply shank 11.

[0017] The pipe or other attachment holder 13 is a so-called multipurpose holder that can support the movable pipe 18, shaft holder 30, etc. in a predetermined position at a positioned location, and, while supporting these, fixes itself to the fixed pipe 15 and the housing of the power drill 100. More specifically, the pipe or other attachment holder 13 is configured to include a first holder 131 having holes formed therein that slidably hold the movable pipe 18 and shaft 20, an Ω-shaped second holder 132 that is molded integrally with the first holder 131 and surrounds the outer periphery of the fixed pipe 15, and a clamping lever 133 that clamps the second holder 132.

[0018] The fixed tube 15 is a cylindrical body and is fixed to the housing of the electric drill 100 directly or via a pipe or other mounting holder 13, while being positioned parallel to the rotation axis of the spindle, shaft 20, and wet core bit 12 within the electric drill 100.

[0019] The movable tube 18 is a cylindrical body whose outer diameter is smaller than the inner diameter of the fixed tube 15, and is housed within the fixed tube 15 or protrudes from an opening of the fixed tube 15 while being positioned parallel to the rotation axis of the spindle, shaft 20, and wet core bit 12 in the power drill 100. Specifically, the central axis of the movable tube 18 is on an extension of the central axis of the fixed tube 15, and the base end of the movable tube 18 is slidably housed within the fixed tube 15. A drainage channel that communicates with a drainage hose 80 is formed in the internal space between the fixed tube 15 and the movable tube 18.

[0020] A water storage holder 16 is fixed to the opposite end, i.e., the tip, of the movable tube 18. The water storage holder 16 comprises a substantially annular water storage section 161, a water absorption section 162, a suction pad 163, a water absorption cap 164, and a holder mounting ring 166. A communication mechanism to the above-mentioned drainage channel is provided at a predetermined position on the holder mounting ring 166.

[0021] 2(c), a gauge 182 is provided on the outer surface of the movable tube 18. This gauge 182 allows the operator to visually and quantitatively grasp how much the movable tube 18 has been displaced, that is, how deep the tip of the wet core bit 12, which displaces along with the movable tube 18, is in the hole to be drilled.

[0022] The wet core bit 12 enters through the water suction portion 162 of the water storage holder 16, passes through the water storage portion 161 and the opening 165 of the water suction cap 164, and heads toward the area to be drilled (not shown). When cooling water is supplied through the wet core bit 12, the water suction portion 162 takes in the cooling water into the water storage portion 161. The water storage portion 161 sends cooling water near the tip of the wet core bit 12 during drilling to cool the area near the tip of the wet core bit 12 which generates heat due to friction, and also watertightly takes in dirty water that has taken in dust and other particles generated during drilling and sends it to the holder mounting ring 166.

[0023] The water absorption cap 164 is formed, for example, from a hollow elastic material, such as a member molded from a rubber material, in a roughly truncated cone shape with an opening 165 formed at the tip. Therefore, the flow rate of the cooling water and wastewater stored in the water storage section 161, especially the wastewater, increases near the opening 165 of the water absorption cap 164 compared to the water absorption section 162, and the wastewater is guided to the suction pad 163, thereby effectively suctioning the wastewater.

[0024] Furthermore, the opening 165 of the water absorption cap 164 is slightly larger than the diameter of the hole drilled by the wet core bit 12. According to experiments by the inventors, by making the opening smaller in diameter than 1.01 to 1.1 times the outer diameter of the wet core bit 12 and setting the angle of the cone to be between 30 degrees and 80 degrees relative to the rotation axis of the wet core bit 12, even if a gap physically occurs between the opening 165 and the wet core bit 12, the elastic force of the water absorption cap 164 and the flow velocity of the wastewater make it difficult for wastewater to leak from the gap during drilling. This has the effect of minimizing the area of ​​the finished surface that comes into contact with and becomes dirty. Wet core bits 12 with various outer diameters can be used depending on the application. In this case, it is desirable to reattach the opening 165 of the water absorption cap 164 to one with the above-mentioned magnification corresponding to the outer diameter of the wet core bit 12.

[0025] The wastewater, whose flow rate has increased by the water absorption cap 164 compared to when it was supplied, is sucked by the suction pad 163 and is sucked into the vacuum device via the holder mounting ring 166, the movable tube 18, the fixed tube 15 and the drain hose 80.

[0026] In this specification, the area including the shank body 111 of the water absorption shank 11, the water storage holder 16, the outer surface of the wet core bit 12 within the water storage holder 16, and the area to be drilled (not shown) is referred to as the "coolant circulation area," and the series of mechanisms for circulating cooling water in this coolant circulation area is referred to as the "coolant circulation mechanism." Because the water storage holder 16 is fixed to the tip of the movable tube 18, its position changes in accordance with the displacement of the movable tube 18. In other words, the coolant circulation area also changes position depending on the work situation.

[0027] Next, the mounting structure of the shaft 20, shaft housing 30, and sensor 60 will be described with reference to FIGS. 3, 4, and 5. FIG. 3 is an exploded view of a water supply and drainage control mechanism including these components, and FIG. 4 is a perspective view of the assembled water supply and drainage control mechanism. FIG. 5(a) is a cross-sectional view showing an example of the structure of the shaft housing 30, and FIG. 5(b) is a partially enlarged view of the portion circled in FIG. 5(a). The shaft 20 is a metal rod arranged parallel to the central axis of the movable tube 18, displaces in the same direction and by the same amount as the movable tube 18 in conjunction with the movable tube 18, and its base end is housed in the shaft housing 30. The tip of the shaft 20 penetrates a guide portion of the switch box 40, i.e., a plate-shaped part having a hole with a diameter slightly smaller than the diameter of the shaft 20. A flange 23 is fixed to the base end of the shaft 20 to prevent it from coming off the shaft housing 30 and to abut against the end of a spring 31 (described later).

[0028] The shaft accommodating body 30 is a cylindrical body with a bottom, in which a shaft engaging portion 302 is formed at an opening 301 and the diameter of the bottom portion tapers away from the opening 301. A spring 31 abuts against the inner wall of the shaft accommodating body 30. When the shaft 20 is accommodated in the cylinder, this spring 31 biases the shaft 20 in a direction away from the shaft accommodating body 30, i.e., toward the drilling site. A flange 23 for pushing the spring and a detection plate 62 are fixed near the base end of the shaft 20, and a male screw is threaded on the side near the tip. A nut 22 is displaceably attached to the male screw portion and functions as a stopper to prevent the shaft 20 from being accommodated in the shaft accommodating body 30 beyond a predetermined depth. The closer the position of the nut 22 is to the shaft accommodating body 30, the shorter the size of the shaft 20 accommodated in the shaft accommodating body 30 (i.e., the shallower the drilling depth of the wet core bit 12). The outer diameter of the nut 22 is selected to be larger than the opening of the shaft accommodating body 30 .

[0029] The shaft 20 and shaft housing 30 together form a control mechanism that allows adjustment of the drilling depth in the drilled area (the amount of protrusion of the wet core bit 12 during drilling) and controls the depth according to the stress the wet core bit 12 receives from the drilled area during drilling. In other words, the tip of the wet core bit 12 and the water storage holder 16 can be biased toward the drilled area before, during, or after drilling begins. This makes it possible to prevent cooling water and wastewater from leaking from the water storage holder 16, at least during drilling.

[0030] The detection metal plate 62 is an L-shaped metal plate fixed near the base end of the shaft 20. It has legs extending perpendicular to the shaft 20 and a flat portion extending parallel to the shaft 20. The detection metal plate 62 moves in response to the displacement of the shaft 20. When the detection metal plate 62 is in its initial position, a proximity sensor 63 is housed in a sensor holder 64 and fixed to the shaft housing 30 directly below the detection metal plate 62. The proximity sensor 63 is, for example, an inductive proximity sensor. When the detection metal plate 62 is in its initial state, it is off. When the detection metal plate 62 moves away from the shaft housing 30, the proximity sensor 63 outputs an on signal to the switch box 40. This on signal initiates the water supply / drain circulation. Alternatively, the proximity sensor 63 may output an off signal to the switch box 40 when the detection metal plate 62 is in its proximity, forcing the power supply to the water supply device and the vacuum device to be turned off. The detection metal plate 62, the proximity sensor 63, and the sensor holder 64 constitute the sensor unit 60.

[0031] The switch box 40 is fixed to the holder mounting ring 166 of the water storage holder 16. In addition to the guide portion, the switch box 40 also has a switch portion that turns on or off by swinging a flat operating lever. The switch portion is linked to the power supply of the water supply device and the power supply of the vacuum device. The switch portion may be a rocker switch that allows the cooling water supply and drainage circulation when on and stops the circulation when off. The switch box 40 is fixed so that the on / off operating line of the switch portion is located on an extension of the central axis of the shaft 20. If the tip of the shaft 20 that passes through the guide portion intersects with the operating line of the switch portion, the switch box 40 is fixed so that the operator cannot turn off the vacuum device. This eliminates the risk of accidentally turning off the switch box 40 and shutting off the vacuum device when drilling with the wet power drill 1.

[0032] The fixed tube 15 and the movable tube 18 are disposed slightly to the left of the central axis of the wet core bit 12 when viewed from the front, and the switch box 40 is disposed slightly to the right of the central axis of the wet core bit 12 when viewed from the front. This allows the size in the Z direction to be reduced when the shaft 20 and the shaft housing 30 are installed.

[0033] As mentioned above, the wet core bit 12 can be freely replaced depending on the diameter of the portion to be drilled. Fig. 6 is a side view of the wet power drill 1 with the wet core bit 12 removed, and Fig. 7 is a side view showing the state of the wet power drill 1 when attempting to attach the wet core bit 12. As shown in these figures, the wet core bit 12 can be attached to the shank body 111 of the water absorption shank 11 after its tip has been inserted through the water storage holder 16. To remove the wet core bit 12, similarly, it can be detached from the shank body 111 of the water absorption shank 11, stored in the water storage holder 16, and then pulled out from the water storage holder 16. In this way, one of the features of the wet-type power drill 1 of this embodiment is that the structure for detachably attaching the wet-type core bit 12 is simplified.

[0034] Next, the structure of the water supply shank 11, particularly the shank body 111, will be described in detail. Fig. 8 is a front view of the water supply shank 11, and Fig. 9 is a side view of the water supply shank 11. The shank body 111 is fixed to the housing of the power drill 100, for example, by a fixing bracket 112. In this example, the drain 112 having an opening / closing lever 113 is fixed to the shank body 111 by a nut 114, but it may also be fixed to the shank body 111 by other means or structures.

[0035] Figure 10 is an H-H cross-sectional view of Figure 9, i.e., a cross-sectional view showing a state without the spindle or wet core bit 12 attached. The chuck body 111 has a cylindrical nut 115 formed at its connecting portion with the spindle, with the opposing side surfaces flat and the remaining portion arc-shaped, and a female thread 111a threaded inside. The chuck body 111 also has a male thread 116 formed at its connecting portion with the wet core bit 12. Correspondingly, the end of the spindle is threaded with a male thread, and the base end of the wet core bit 12 is threaded with a female thread. In Figure 10, reference numeral 117 denotes an attachment for a suction hose (not shown).

[0036] In the case of wet-type electric drills with water supply shanks, the connection between the water supply shank and spindle is often a chuck (or sleeve) type that accepts a hexagonal shaft or similar for one-touch attachment and detachment. The same is true for the connection with the core bit. With such chuck types, gaps inevitably form between the chucks. Furthermore, the pressure between each chuck may not be uniform. While this makes it easy to attach and detach the spindle or core bit, it can lead to water leakage. Furthermore, the gaps cause vibration noise when the spindle or core bit rotates. Furthermore, if the pressure between each chuck is not uniform, the axis of the spindle or core bit may wobble during rotation, resulting in vibration noise. Furthermore, if the axis of the spindle or core bit wobble during rotation, the drilling diameter may become larger or unexpected forces may be applied to the wet-type core drill, making it more susceptible to breakage. In the wet power drill 1 of this embodiment, the shank body 111 of the water supply shank 11 is made to have a fixed structure as shown in Figures 9 and 10, thereby aligning the rotational axis of the spindle and the rotational axis of the wet core bit 12 and solving the above problem.

[0037] Next, the operation of the wet-type power drill 1 of this embodiment will be described. FIG. 11 is a side view showing the initial state of the wet-type power drill 1. The tip of the wet-type core bit 12 is housed in the water storage holder 16. FIG. 12 shows the relative positions of the detection plate 62 and the proximity sensor 63 in the initial state. In this state, the switch box 40's function of locking the power off of the vacuum device is not activated, but the proximity sensor 63 outputs an OFF signal to the switch box 40 or does not output an ON signal, so the power to the water supply device and vacuum device will not be turned on by mistake during operation. This reliably prevents water leakage and further improves safety during operation.

[0038] Figure 13 is a side view of the wet power drill 1 as it begins to cut. The tip of the wet core bit 12 begins to protrude from the water reservoir holder 16. As the movable tube 16 begins to contract, the tip of the shaft 20 penetrates the hole in the guide portion of the switch box 40 and reaches the on / off operating line of the switch, locking the vacuum device to prevent it from being accidentally turned off. When the tip of the shaft 20 penetrates a predetermined distance, the hole in the guide portion comes into contact with the nut 22 of the shaft 20, preventing further displacement of the shaft 20, i.e., preventing the wet core bit 12 from drilling deeper.

[0039] Figure 14 shows the relative positional relationship between the detection metal plate 62 and the proximity sensor 63 in this state. The proximity sensor 63 sends an ON signal to the switch box 40 or stops outputting an OFF signal. This allows the water supply device to be turned on, and power control is performed via the switch box 40.

[0040] Figure 15 is a side view of the wet power drill 1 showing the movable tube 18 and shaft 20 in their most retracted state. In other words, this is the state in which the nut 22 on the shaft 20 has been removed or moved to the rightmost screw groove as viewed from the right side. In this state, the tip of the wet core bit 12 protrudes from the water storage holder 16. Figure 16 is a diagram showing the relative positional relationship between the detection metal plate 62 and the proximity sensor 63 in this state, with both the water supply device and the vacuum device kept powered on.

[0041] As described above, the wet power drill 1 of this embodiment includes the shaft 20 and the shaft housing 30, and the displacement of the moving movable tube 18 and the wet core bit 12 can be increased, enabling deeper drilling. Furthermore, by changing the position of the nut 22 threaded onto the threads of the shaft 20, the drilling depth can be finely adjusted to prevent the drilling from becoming too deep. Furthermore, the provision of the sensor unit 60 prevents accidental water supply from the water supply device or inadvertent operation of the vacuum device, which is a source of noise, in the initial state shown in FIG. 11 .

[0042] Although the present embodiment illustrates a switch unit as the switch of the switch box 40, the switch according to the present invention may be another type of switch, such as a push button switch that turns on or off by pressing an operating unit, or a toggle switch that turns on or off by swinging a rod-shaped operating unit. Even in this case, the switch is mounted so that when the movable tube 18 is retracted, the shaft 20 intersects with the operating line of the switch's on action, thereby inhibiting the switch's off action. For example, in the case of a push button switch, it is preferable to mount the switch so that when the movable tube 18 is retracted, the shaft 20 is positioned on the operating line of the push action of the operating unit, such as a push button.

[0043] In this embodiment, an example has been described in which the shaft 20 and the shaft accommodating body 30 incorporating the spring 31 are provided with an elastic function for adjusting the drilling depth, but it is also possible to make the length of the movable tube 18 longer while installing a spring inside the inner wall of the fixed tube 15.

[0044] In this embodiment, an example of a wet electric drill 1 has been described, but the wet drilling tool of the present invention may be any drilling tool to which a water supply and drainage control mechanism can be attached, and can be applied not only to electric drills, but also to electric punches, hand drills, electric reamers, electric cutters, etc.

Claims

1. a refrigerant circulation mechanism that displaceably forms a refrigerant circulation region that includes the outer surface of the wet core bit and a portion to be drilled by the wet core bit, and circulates a predetermined refrigerant in the refrigerant circulation region; The wet core bit has a tip that protrudes from the refrigerant circulation area toward the drilled area, and includes a rod-shaped shaft that urges the refrigerant circulation area in the direction at the start of drilling or during drilling at a location separate from a tube that forms a drainage path for the refrigerant circulating in the refrigerant circulation area, and is characterized by being equipped with a control mechanism that controls the drilling depth in the drilled area through the shaft. Wet drilling tool.

2. The control mechanism further includes a movable tube that is displaced parallel to the axis of the wet core bit according to the depth of the drilling in the drilled portion, thereby displacing the refrigerant circulation region, a fixed tube that accommodates the movable tube, and a shaft accommodating body that is provided with a spring that urges the shaft in the direction when the shaft is accommodated, The shaft is linked to the displacement of the movable tube. The wet drilling tool of claim 1 .

3. a sensor that detects that the refrigerant circulation region has separated from the perforated portion; and a supply control means for switching the mode of the supply operation of the refrigerant to the refrigerant circulation area when the sensor detects the separation.

3. A wet drilling tool according to claim 1 or 2.

4. The present invention further includes a switch for switching on and off one or both of an injection device that injects the refrigerant into the refrigerant circulation area and a vacuum device that sucks up refrigerant mixed with dust generated by drilling, and the axis of the shaft is located on an operating line of the on operation or off operation of the switch. The wet drilling tool of claim 2.

5. The control mechanism further includes a gauge that visually indicates the displacement of the movable tube. A wet drilling tool according to claim 2 or 4.

6. a refrigerant circulation mechanism that displaceably forms a refrigerant circulation region that includes the outer surface of the wet core bit and a portion to be drilled by the wet core bit, and circulates a predetermined refrigerant in the refrigerant circulation region; a control mechanism including a rod-shaped shaft that causes the tip of the wet core bit to protrude from the refrigerant circulation region toward the drilled portion, and that urges the refrigerant circulation region in the direction at the start of drilling or during drilling at a location away from a tube that forms a drainage path for the refrigerant circulating in the refrigerant circulation region, and that controls the drilling depth in the drilled portion through the shaft; the refrigerant circulation mechanism includes a water supply shank that injects the refrigerant into the refrigerant circulation region through the wet core bit and transmits a rotational driving force applied from a rotational driving mechanism to the wet core bit; The axis of the wet core bit connected to the water supply shank is aligned with the rotation axis of the rotation drive mechanism, The water supply shank is a wet drilling tool characterized in that at least one of a first connecting portion that connects the base end of the wet core bit and a second connecting portion that connects the rotation drive mechanism has a male thread structure or a female thread structure.

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