JP2015188988A - hole machining tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply efficiently coolant to a cutting blade so as to ensure cooling and lubrication of the blade although an amount of protrusion of the cutting blade in a radial direction can be adjusted.SOLUTION: A shaft-like tool main body 1 that is rotated around a shaft line O is formed with a recessed place 2 that is opened to an outer peripheral surface of the tool main body 1 and recessed in a radial direction with respect to the shaft line O. In the recessed place 2, a cutting unit 11 equipped with a cutting blade 13 is installed so that an amount of protrusion of the cutting blade 13 in a radial direction of the tool main body 1 can be adjusted. In the tool main body 1, a coolant supply hole 4 extending in a direction of the shaft line O is formed, and the coolant supply hole 4 is communicated with a coolant spray hole 20 formed in the cutting unit 11 to supply coolant toward the cutting blade 13.

Description

  The present invention relates to a drilling tool used for finishing a crankshaft hole of an automobile engine, for example.

  As such a hole drilling tool, Patent Document 1 includes a rotating rod that can be rotated and moved in the axial direction, and a support portion that supports the rotating rod so that the rotating rod can be rotated and moved in the axial direction. There has been proposed one provided with fluid supply means for supplying fluid (mist) to the tool from a flow path formed in a rotating rod through a support portion. In addition, in the patent document 2 and patent document 3, the inventor of the present invention also attaches a cutting unit having a cutting edge to a recess formed in the tool body, and determines the protrusion amount of the cutting blade in the radial direction of the tool body. Proposals have been made for fine-tuning with a cutting unit.

Japanese Patent Laying-Open No. 2005-177872 JP 2007-167993 A JP 2007-167994 A

  However, in the drilling tool described in Patent Document 1, since the flow path of the fluid supply means is opened on the outer peripheral surface of the rotating rod, it is cut like the drilling tool described in Patent Documents 2 and 3. When the cutting blade is arranged through a cutting unit capable of finely adjusting the protruding amount of the blade, the flow path must be opened at a position away from the cutting blade while avoiding a recess to which the cutting unit is attached. For this reason, it becomes difficult to efficiently supply the fluid to the cutting blade for cooling and lubrication.

  In the drilling tool described in Patent Document 1, in order to supply fluid to a plurality of tools arranged in the axial direction of the rotating rod, the flow path in the rotating rod extends along the axial direction, and this flow As described above, a fluid is supplied from the passage by forming a branch passage so as to open to the outer peripheral surface of the rotating rod. However, since the flow path extending in the axial direction is perforated at a position away from the axis of the rotating rod toward the outer peripheral side, the position of the center of gravity of the rotating rod is also shifted to the outer peripheral side, and the rotating rod is rotated at high speed. There is also a possibility that the processing accuracy is deteriorated by bending.

  The present invention has been made under such a background. First, even if the amount of protrusion in the radial direction of the cutting blade can be adjusted, the coolant is efficiently supplied to the cutting blade for reliable cooling and lubrication. An object of the present invention is to provide a drilling tool that can be achieved, and secondly, it is an object of the present invention to provide a drilling tool that does not cause deterioration in machining accuracy even when the tool body is rotated at high speed.

  In order to solve the above-described problem and achieve the first object, the present invention provides a shaft-shaped tool body that is rotated around an axis, and is opened in the outer peripheral surface of the tool body so as to be radial with respect to the axis. In this recess, a cutting unit having a cutting blade is attached so as to be able to adjust the protruding amount of the cutting blade in the radial direction, and the tool body has the axial direction. A coolant supply hole extending in the direction of the coolant is formed, and the coolant supply hole communicates with a coolant injection hole formed in the cutting unit to supply the coolant toward the cutting blade.

  In the hole drilling tool configured in this way, the coolant injection hole formed in the cutting unit that enables adjustment of the protruding amount of the cutting blade communicates with the coolant hole formed in the tool body, and therefore the coolant of the cutting unit. The injection hole can be opened at a position close to the cutting blade. Therefore, the coolant can be efficiently supplied from the coolant injection hole to the cutting edge, and the cutting edge and the cutting site by the cutting edge can be reliably cooled and lubricated.

  Further, since the coolant supply hole of the tool body communicates with the coolant injection hole of the cutting unit in this way and the coolant is supplied, it is not necessary to form the coolant supply hole so as to avoid the cutting unit. For this reason, by forming the coolant supply hole along the axis, the center of gravity of the tool body can be disposed in the vicinity of the axis, and the second balance can be achieved by improving the dynamic balance of the tool body. Aim can be achieved.

  In particular, when the coolant supply hole is formed along the axis of the tool body, the radial width with respect to the axis is at least one of the outer peripheral surface of the cutting unit and the inner peripheral surface of the recess. By forming a communication portion larger than the inner diameter of at least one of the coolant supply hole and the coolant injection hole, the coolant supply hole and the coolant injection hole are formed so as to communicate with each other via the communication portion. For example, when the same cutting unit is mounted on a tool body having a different outer diameter, even if the mounting position of the cutting unit with respect to the axis of the tool body is different, the coolant is reliably transferred from the coolant supply hole to the coolant injection hole via the communication portion. It becomes possible to supply to.

  As described above, according to the present invention, even if the protruding amount of the cutting edge can be adjusted, the coolant can be efficiently supplied toward the cutting edge, and the cutting edge and the cutting site can be reliably connected. Cooling and lubrication can be achieved. Further, by forming the coolant supply hole along the axis of the tool body, it is possible to suppress the bending and prevent deterioration of the machining accuracy even if the tool body is rotated at a high speed.

It is a fragmentary sectional side view which shows the 1st Embodiment of this invention. It is ZZ sectional drawing in FIG. It is a sectional side view of the cutting unit provided with the cutting blade attached to embodiment shown in FIG. It is a top view of the cutting unit shown in FIG. It is a bottom view of the cutting unit shown in FIG. It is a partial front view of the cutting unit shown in FIG. It is a sectional side view of the cutting unit provided with the cutting blade attached to the 2nd Embodiment of this invention. It is a partially broken bottom view of the cutting unit shown in FIG. It is a side view of the washer of the cutting unit shown in FIG. It is ZZ sectional drawing in FIG. 7 of the cartridge of the cutting unit shown in FIG. It is a fragmentary sectional side view of the 2nd Embodiment of this invention which attached the cutting unit shown in FIG. It is a fragmentary sectional side view which shows the modification of 2nd Embodiment shown in FIG. It is a partial sectional side view which shows the other modification of 2nd Embodiment shown in FIG.

  1 and 2 are partial side sectional views showing an embodiment of the drilling tool of the present invention, and FIGS. 3 to 6 show recesses formed in the tool body 1 of the drilling tool of this embodiment. The cutting unit 11 attached to 2 is shown. The cutting unit 11 in the present embodiment has substantially the same configuration as the fine-adjusting cutting tool described in Patent Document 2 described above, for example, except for a coolant injection hole described later.

  That is, in the cutting unit 11 of the present embodiment, the cutting edge 13 is provided at the tip along the unit center line C of the cutting unit 11 on the inner peripheral portion of the cylindrical bush 12 mounted in the recess 2. While the cartridge 14 is inserted, a washer 15 is attached to the rear end of the cartridge 14, and a biasing member 16 that biases the cartridge 14 toward the rear end via the washer 15 between the washer 15 and the bush 12. Further, an adjustment nut 17 that abuts against the front end surface of the bush 12 is screwed to the cartridge 14.

  The bush 12 has a multi-stage cylindrical shape centering on the unit center line C whose outer diameter is reduced by one step toward the rear end side (lower side in FIGS. 1 and 3) and whose inner diameter is reduced by one step. The inner periphery of the rear end portion is an accommodation hole 12A for accommodating the urging member 16. The urging member 16 in the present embodiment is a plurality (six) of compression coil springs, and the urging member 16 has a center line parallel to the unit center line C and surrounds the housing hole 12A. It is accommodated with a gap in the direction.

  Further, the rear end surface of the bush 12 is formed with a plurality of (two) keys 12B protruding toward the rear end side so as to protrude toward the rear end side at equal intervals in the circumferential direction. Further, on the outer periphery of the front end of the bush 12, a notch 12C having a substantially semicircular cross section that can be engaged with the head of a unit set screw 18 that fixes the cutting unit 11 to the tool body 1 and accommodates the head. A plurality (two) are formed at equal intervals in the circumferential direction.

  The cutting blade 13 is formed in a cutting insert 13A made of a hard material such as cemented carbide, which is detachably attached to an insert mounting seat formed at the tip of the cartridge 14. In this embodiment, the cutting insert 13A is formed in a rhombus plate shape, and the rake face 13B forming the rhombus is parallel to the unit center line C and is directed in the tool rotation direction described later, and the sharp corner of the rake face 13B is formed. The cutting blade 13 used for cutting formed in the part is protruded toward the front end side in the unit center line C direction, and is attached by a clamp screw 13C.

  Further, the portion of the cartridge 14 on the rear end side with respect to the front end where the insert mounting seat is formed is formed in a multi-stage columnar shape centering on the unit center line C whose outer diameter is reduced by one step toward the rear end. Has been. Of these, a male screw portion 14A is formed on the outer periphery of the large-diameter front end portion, and the outer diameter of the rear end portion of the small-diameter cartridge 14 can be fitted to a portion of the inner peripheral portion of the bush 12 that has been reduced by one step. It is said to be a big size.

  Further, the rear end surface of the cartridge 14 is notched in a V-shape projecting toward the rear end side by two planes extending in a direction intersecting with a straight line orthogonal to the unit center line C as shown in FIG. . Further, a screw hole 14B is formed along the unit center line C from the rear end surface toward the front end side.

  On the other hand, the washer 15 has a shaft portion having an outer diameter equal to that of the rear end portion of the cartridge 14 and a disk portion having an outer diameter slightly smaller than the outer diameter of the rear end portion of the bush 12. The surface is cut out into a concave V-shape opposite to the V-shape formed by the rear end surface of the cartridge 14 so as to be in close contact with the rear end surface. Further, on the outer periphery of the disc portion, key grooves 15A that can be fitted with the keys 12B protruding from the rear end face of the bush 12 are formed at equal intervals (two) in the circumferential direction as the keys 12B. From the rear end surface of the disc portion to the front end surface of the shaft portion, a multi-stage inner diameter through-hole 15B is formed along the unit center line C that is reduced in diameter by one step toward the front end side.

  Further, the adjusting nut 17 has a multi-stage annular shape in which the outer diameter of the front end portion is one step larger than the outer diameter of the rear end portion, and the outer diameter of the front end portion is larger than the outer diameter of the front end portion of the bush 12. The outer diameter of the rear end portion is set to a size that can be fitted to the inner peripheral portion of the front end of the bush 12. A female screw portion 17 </ b> A that is screwed with the male screw portion 14 </ b> A of the cartridge 14 is formed on the inner peripheral portion of the adjustment nut 17.

  Further, on the outer periphery of the tip of the adjusting nut 17, a notch 17 B having a semicircular cross section that can communicate with the notch 12 C and pass through the head of the unit set screw 18 at a position corresponding to the notch 12 C of the bush 12. Is formed. Further, at a position avoiding these notches 17B, an engagement portion (an engagement hole extending in a radial direction with respect to the unit center line C in this embodiment) 17C that engages with a tool such as a wrench is circumferentially provided. A plurality (four) are formed at equal intervals.

  Such a cutting unit 11 has a rear end of the cartridge 14 after the female nut 17A is screwed into the male thread 14A of the cartridge 14 having the cutting insert 13A attached to the front end and the adjusting nut 17 is attached. And the rear end of the adjusting nut 17 is inserted into the inner peripheral portion of the front end of the bush 12, and then the rear end of the cartridge 14 in the housing hole 12A. The urging member 16 is housed in a compressed state around the shaft so that the front end surface of the shaft portion of the washer 15 having an uneven V shape and the rear end surface of the cartridge 14 are brought into close contact with each other, and the key groove 15A is fitted into the key 12B. Further, the washer set screw 19 inserted through the through-hole 15B is screwed into the screw hole 14B for assembly.

  In the cutting unit 11 assembled in this way, the urging member 16 is compressed, so that the cartridge 14 and the adjustment nut 17 are urged to the rear end side via the washer 15 and the washer set screw 19, and the adjustment nut Since the rear end surface of the distal end portion 17 is in strong contact with the distal end surface of the bush 12, the working tool is engaged with the engaging portion 17C and the adjustment nut 17 is rotated about the unit center line C in this state. As a result, the female screw portion 17A of the adjustment nut 17 and the male screw portion 14A of the cartridge 14 are screwed, and the positions of the cartridge 14 and the cutting blade 13 in the unit center line C direction are set to the pitch of the female and male screw portions 14A and 17A. Fine adjustments can be made accordingly. At this time, the cartridge 14, the washer 15 and the bush 12 do not rotate around the unit center line C because the key groove 15A and the key 12B are fitted.

  The tool body 1 of the drilling tool of this embodiment to which such a cutting unit 11 is attached is formed in a columnar shape centering on the axis O as shown in FIG. By being connected to the rotating shaft, it is moved in the direction of the axis O while being rotated around the axis O in the tool rotating direction T, and the cutting blade 13 of the cutting unit 11 is used for finishing the crankshaft hole of the engine. Used.

  The outer peripheral surface of the tool body 1 includes a flat bottom surface 3A parallel to the axis O, and a pair of inclined flat wall surfaces 3B that cut off from both ends of the bottom surface 3A in the axis O direction to the outer periphery of the tool body 1. A unit mounting seat 3 is formed. The bottom surface 3 </ b> A of the unit mounting seat 3 is formed with the recess 2 that is open to the bottom surface 3 </ b> A and is recessed in the radial direction with respect to the axis O, and the cutting unit 11 is attached to the recess 2. Although illustration is omitted, a plurality of unit mounting seats 3 and recesses 2 are formed in the tool body 1 at intervals in the direction of the axis O, and a cutting unit 11 is mounted in each of these recesses 2.

  The recess 2 is formed in a circular cross section having a center line orthogonal to the axis O and extends beyond the axis O from the bottom surface 3A, and its inner diameter extends from the opening to the bottom surface 3A of the unit mounting seat 3 from the axis O. The inner diameter on the opening side to the bottom surface 3A is the tip of the bush 12 of the cutting unit 11, and the inner diameter of the portion on the radially inner side is the inner diameter of the bush 12. The rear end portions are sized to fit each other. In addition, the bottom end 3A and the front end surface of the bush 12 are formed to be substantially flush with each other in a state where the front and rear end portions of the bush 12 are fitted and the cutting unit 11 is accommodated in the recess 2.

  Further, the bottom surface 3A of the unit mounting seat 3 has the same number of screw holes as the cutouts 12C and 17B on the periphery of the opening of the recess 2, and the half of the cutouts 12C and 17B form a cross section when the cutting unit 11 is attached. The unit set screw 18 is screwed into these screw holes so that the head passes through the notch 17B, and is received and engaged in the notch 12C. 11 is attached to the tool body 1 while the adjustment nut 17 is rotatable. A small-diameter hole 2A is formed so as to penetrate from the bottom surface of the recess 2 to the opposite side of the outer peripheral surface of the tool body 1 from the unit mounting seat 3, and is sealed with a plug 2B.

  Therefore, in the cutting unit 11 attached in this way, the unit center line C is arranged so as to be orthogonal to the axis O of the tool body 1, and the cutting insert 13A has a rake face 13B substantially perpendicular to the tool rotation direction T. It arrange | positions so that it may oppose. Further, as the position of the cutting blade 13 in the unit center line C direction is finely adjusted by the rotation of the adjusting nut 17 as described above, the protruding amount of the cutting blade 13 in the radial direction with respect to the axis O of the tool body 1 is fine. Adjustable.

  A coolant supply hole 4 extending in the direction of the axis O is formed in the tool body 1, and a coolant injection hole 20 is formed in the cutting unit 11. The coolant supply hole 4 communicates with the coolant injection hole 20. The coolant is supplied toward the cutting edge 13. Here, the coolant supply hole 4 of the tool body 1 is a circular hole having a constant inner diameter with the axis O as the center, that is, extends along the axis O, and is a recess in a portion where the rear end of the bush 12 is fitted. 2 is opened on both sides in the direction of the axis O on the inner peripheral surface.

  On the other hand, at the rear end portion of the bush 12 of the cutting unit 11, a through-hole-shaped communication portion 12 </ b> D that penetrates the rear end portion in the diameter direction with respect to the unit center line C is attached to the recess 2. Are formed so as to communicate with the coolant supply hole 4. The communication portion 12D has a width in the unit center line C direction on the outer peripheral surface of the rear end portion of the bush 12, that is, a radial width with respect to the axis O of the tool body 1 larger than the inner diameter of the coolant supply hole 4. It is formed in a long hole extending in the unit center line C direction. Therefore, the coolant supply hole 4 communicates with the accommodation hole 12A in which the urging member 16 of the rear end inner peripheral portion of the bush 12 is accommodated via the communication portion 12D.

  Further, the coolant injection hole 20 avoids the urging member 16 that is accommodated in the bush 12 at the bottom surface of the accommodation hole 12A around the rear end portion of the cartridge 14 protruding into the accommodation hole 12A. Thus, two openings are made in the direction of the axis O with the unit center line C in between. The coolant injection hole 20 of the bush 12 thus opened extends toward the unit center line C toward the distal end side of the cutting unit 11 and opens on the inner peripheral surface of the portion of the bush 12 having a reduced diameter. The inner diameter of the coolant injection hole 20 of the bush 12 is set smaller than the inner diameter of the coolant supply hole 4.

  Also in the cartridge 14, these coolant injection holes 20 are also cut from the inner peripheral surface of the one-stage reduced diameter portion of the bush 12 into the rear end portion of the cartridge 14 that fits into the one-stage reduced diameter portion. The unit 11 extends toward the unit center line C toward the unit center line C substantially in parallel with or parallel to the coolant injection hole 20 of the bush 12, and opens at the bottom of the screw hole 14 </ b> B of the cartridge 14. The length of the threaded portion of the washer set screw 19 is such that the washer set screw 19 is screwed into the screw hole 14B with the shaft tip end surface of the washer 15 having an uneven V shape and the rear end surface of the cartridge 14 in close contact with each other. The length is set such that a space is formed in the bottom of the screw hole 14B where the coolant injection hole 20 is opened without reaching the bottom of the screw hole 14B.

  Furthermore, a branch hole 20A is formed from the hole bottom of the screw hole 14B toward the tip side of the cartridge 14, that is, the outer peripheral side of the tool body 1, and the branch hole 20A is an extension line L to the tip side. Extends substantially so as to be parallel to the rake face 13B of the cutting insert 13A so as to reach the cutting edge 13 used for cutting as shown in FIGS. 1 and 3 when viewed from the direction facing the rake face 13B. ing. The inner diameter of the branch hole 20A is smaller than the inner diameter of the coolant injection hole 20 formed from the bush 12 to the bottom of the screw hole 14B of the cartridge 14.

  In this embodiment, a counterbore portion 14C having a width in the unit center line C direction larger than the opening is formed in the opening of the coolant injection hole 20 on the outer peripheral surface of the rear end of the cartridge 14 in the radial direction of the cartridge 14. It is formed so as to have a flat “C” shape. The coolant injection hole 20 of the cartridge 14 opens at the center part in the unit center line C direction (the center part in the width direction of the concave groove 14C) on the bottom surface facing the outer peripheral side of the counterbore part 14C.

  In the hole drilling tool configured as described above, the adjustment nut 17 is rotated to finely adjust the protruding amount of the cutting blade 13, and the tool body 1 is rotated about the axis O as described above while being in the direction of the axis O. The cutting blade 13 cuts the workpiece, and coolant such as cutting fluid is supplied from the machine tool side to the coolant supply hole 4 at high pressure. As shown by the black arrow lines in FIGS. 1 and 2, the coolant supplied in this way is one of the openings of the coolant supply holes 4 opened on both sides in the axis O direction of the inner peripheral surface of the recess 2 (FIGS. 1 and 2). In FIG. 2, the gas flows into the accommodation hole 12 </ b> A from the right opening) via the communication portion 12 </ b> D of the bush 12 of the cutting unit 11.

  The coolant flowing into the housing hole 12A is housed in the urging member 16 around the rear end portion of the cartridge 14 in the housing hole 12A and the shaft portion of the washer 15 as shown by the black arrow lines in FIGS. The coolant supply hole 4 that opens into this opening is filled from the other opening (the left opening in FIGS. 1 and 2) of the coolant supply hole 4 that fills the defined space and opens in the inner peripheral surface of the recess 2. The space is supplied to the next recess 2 (not shown), and sequentially fills the space in the receiving hole 12A of the cutting unit 11 attached to the plurality of recesses 2 described above.

  Then, a part of the coolant filling the inside of the accommodation hole 12A flows into the coolant injection hole 20 of the bush 12 and the cartridge 14, and is directed from the bottom of the screw hole 14B to the cutting blade 13 through the branch hole 20A. Then, the cutting blade 13 and the cutting part of the work material are cooled and lubricated. Accordingly, the coolant injection hole 20 can be supplied from the branch hole 20A toward the cutting edge 13 through the cutting unit 11 provided with the cutting edge 13 so as to communicate with the coolant supply hole 4 of the tool body 1. The branch hole 20 </ b> A of the hole 20 can be opened at a position close to the cutting edge 13. For this reason, even if the cutting blade 13 is provided in the cutting unit 11 capable of adjusting the protrusion amount, the coolant can be efficiently supplied to reliably cool and lubricate the cutting blade 13 and the cutting site.

  Further, since the coolant injection hole 20 is formed in the cutting unit 11 and communicates with the coolant supply hole 4 of the tool body 1 as described above, it is not necessary to form the coolant supply hole 4 so as to avoid the cutting unit 11. . In this embodiment, since the coolant supply hole 4 is formed along the axis O that is the center of the cross section of the cylindrical tool body 1, the position of the center of gravity of the tool body 1 moves close to the axis O. The balance can be improved, and even if the tool body 1 is rotated at a high speed, no bending occurs, and deterioration of machining accuracy can be prevented.

  On the other hand, in the present embodiment, as described above, the coolant is filled in the housing hole 12A in which the urging member 16 on the inner periphery of the rear end of the bush 12 in the cutting unit 11 is housed, and from the housing hole 12A, the coolant injection hole 20 and its The coolant is sprayed to the cutting blade 13 through the branch hole 20A. In this embodiment, the space filled with the coolant in the housing hole 12A is such that the urging member 16 around the rear end portion of the cartridge 14 and the shaft portion of the washer 15 is spaced in the circumferential direction at the inner peripheral portion of the rear end of the bush 12. A space having an annular cross section around the unit center line C to be accommodated, and a large capacity can be secured, so that the coolant filled in such a space can be connected to the coolant injection holes 20 and the branch holes 20A. By being injected through the coolant, the coolant can be supplied to the cutting blade 13 stably at all times.

  Furthermore, even if a plurality of recesses 2 are formed in the tool body 1 at intervals in the direction of the axis O as described above, and the cutting unit 11 is attached to each recess 2, the inside of the accommodation hole 12 </ b> A is thus maintained. Even when coolant is supplied only from one end of the tool body 1, the cutting unit 11 attached to the recess 2 on the other end branches off. It is possible to prevent the supply amount and pressure of the coolant ejected from the hole 20A from decreasing, and to sufficiently distribute the coolant. Therefore, it is possible to reliably supply coolant to the cutting blade 13 and the cutting site over the entire length of the tool body 1 to achieve efficient cooling and lubrication.

  Furthermore, in this embodiment, a counterbore 14C is formed on the outer peripheral surface of the rear end portion of the cartridge 14 of the cutting unit 11, and the width of the counterbore 14C in the unit center line C direction is larger than the inner diameter of the coolant injection hole 20. The coolant injection hole 20 of the bush 12 and the coolant injection hole 20 of the cartridge 14 communicate with each other through the concave groove 14C. For this reason, even if the cartridge 14 moves in the unit center line C direction with respect to the bush 12 by adjusting the protruding amount of the cutting blade 13, the coolant is surely supplied to the cartridge 14 via the counterbore portion 14C and branched. It can be ejected from the hole 20A.

  In this embodiment, the counterbore portion 14C is formed on the outer peripheral surface of the rear end portion of the cartridge 14 as described above. However, the counterbore portion 14C may be formed on the inner peripheral surface of the rear end portion of the bush 12. 12 may be formed on both the inner peripheral surface of the rear end portion and the outer peripheral surface of the rear end portion of the cartridge 14.

  Next, FIGS. 7 to 10 show the cutting unit 21 attached to the drilling tool of the second embodiment of the present invention, and FIGS. 11 to 13 show the individual cutting units 21 attached. The drilling tool of 2nd Embodiment and its modification are shown. In these drawings, the same reference numerals are assigned to portions common to the first embodiment to simplify the description.

  In the cutting unit 11 in the first embodiment, as described above, the compression coil spring as the biasing member 16 is accommodated in the accommodation hole 12A having an annular cross-section with the unit center line C as the center. In contrast, in the cutting unit 21 of the second embodiment, the inner peripheral portion of the rear end of the bush 12 extends to the rear end side while being reduced in diameter by one step, and is formed between the outer peripheral surface and the meat. In the thick wall portion, a circular cross-sectional accommodation hole 12A for individually accommodating a plurality (six) of urging members (compression coil springs) 16 is formed at intervals in the circumferential direction.

  Further, a coolant injection hole 20 is formed in the wall portion of the rear end inner peripheral portion of the bush 12 so as to extend in parallel with the axis O of the tool body 1 while avoiding the accommodation hole 12A. On the other hand, at the rear end portion of the cartridge 14, the coolant injection hole of the cartridge 14 communicating with the coolant injection hole 20 of the bush 12 is connected to the rear end inner peripheral portion of the bush 12 extending to the rear end side. 20 extends coaxially and has the same inner diameter and is orthogonal to the unit center line C.

  Further, the coolant injection hole 20 of the cartridge 14 is orthogonal to the screw hole 14 </ b> B of the cartridge 14. Here, the washer set screw 19 screwed into the screw hole 14B is shorter than that of the first embodiment, and the coolant injection hole 20 does not protrude from the portion intersecting the screw hole 14B. A branch hole 20A is formed at the hole bottom portion of the screw hole 14B on the tip side of the cutting unit 21 and opens at the tip of the cartridge 14 so as to inject coolant to the cutting edge 13.

  Also in the present embodiment, the outer peripheral surface of the rear end portion of the bush 12 where the coolant injection hole 20 opens is a communication whose width in the unit center line C direction is larger than the inner diameters of the coolant injection hole 20 and the coolant supply hole 4. Part 12D is formed. As shown in FIG. 9, the communication portion 12 </ b> D in the present embodiment is opened in an oval shape extending in the direction of the unit center line C, and the coolant injection hole 20 of the bush 12 is formed at the distal end side of the cutting unit 21. . Further, on the rear end side of the cutting unit 21 with respect to the opening of the coolant injection hole 20, the communication part 12D is inclined so as to go to the inner peripheral side as it goes to the front end side as shown in FIG.

  As shown in FIGS. 11 to 13, the cutting unit 21 of the second embodiment configured in this way is also fitted with a unit set screw 18 in which the bush 12 is accommodated in the recess 2 of the tool body 1, and the cutting blade 21 13 is used for finishing the crankshaft hole after adjusting the amount of protrusion. At this time, the coolant supplied to the coolant supply hole 4 of the tool body 1 is injected from the branch hole 20 </ b> A through the bushing 12 and the coolant injection hole 20 of the cartridge 14 from the communication portion 14 </ b> D and supplied to the cutting blade 13.

  Therefore, also in the second embodiment, the same effect as that of the first embodiment can be obtained. In this embodiment, since the coolant injection hole 20 extends linearly so as to be orthogonal to the unit center line C and communicates with the coolant supply hole 4, there is little resistance when supplying the coolant, and the tool body Even if the cutting units 21 are attached to the plurality of recesses 2 in the direction of one axis O, the coolant can be quickly supplied to all the cutting units 21 and the coolant injection holes 20 can be formed relatively. The advantage of being easy is also obtained. In addition, since the biasing member 16 such as a compression coil spring is rarely exposed to the coolant, corrosion or the like can be prevented.

  Further, also in the present embodiment, the communication portion 12D having a width in the unit center line C direction larger than the inner diameter of the coolant injection hole 20 or the coolant supply hole 4 is formed in the opening portion of the coolant injection hole 20 to the outer peripheral surface of the cutting unit 21. Is formed. Therefore, as shown in FIGS. 11 to 13, when the cutting unit 21 is attached to a tool body having a different outer diameter, the coolant supply hole 4 may be formed along the axis O of the tool body 1 in any case. The coolant can be introduced into the coolant injection hole 20 through the communication portion 12D and reliably injected onto the cutting blade 13.

  In the hole drilling tool shown in FIG. 13 having the largest outer diameter of the tool body 1 among these, the portion of the coolant supply hole 4 that communicates with the coolant injection hole 20 is also directed toward the coolant injection hole 20. The communication portion 4A is formed obliquely, thereby enabling a more reliable and smooth supply of coolant. As described above, the communication portions 12D and 4A may be formed only on the cutting unit 21, or may be formed only on the tool body 1, or may be formed on both the cutting unit 21 and the tool body 1.

DESCRIPTION OF SYMBOLS 1 Tool main body 2 Recessed part 4 Coolant supply hole 11, 21 Cutting unit 12 Bushing 4A, 12D Communication part 13 Cutting blade 14 Cartridge 14B Screw hole 14C Counterbore part 15 Washer 16 Energizing member 17 Adjustment nut 20 Coolant injection hole 20A Coolant injection hole 20 branch holes O Tool body 1 axis T Tool rotation direction C Unit center line

Claims (3)

  A shaft-shaped tool body that is rotated around the axis is formed with a recess that opens in the outer peripheral surface of the tool body and is recessed in the radial direction with respect to the axis, and a cutting unit having a cutting edge is formed in the recess. The cutting amount of the cutting blade in the radial direction is attached to be adjustable, and a coolant supply hole extending in the axial direction is formed in the tool body, and the coolant supply hole is formed in the cutting unit. A drilling tool, wherein the coolant is supplied to the cutting blade in communication with the coolant injection hole.   The hole machining tool according to claim 1, wherein the coolant supply hole is formed along the axis.   At least one of the outer peripheral surface of the cutting unit and the inner peripheral surface of the recess has a communication portion whose radial width with respect to the axis is larger than the inner diameter of at least one of the coolant supply hole and the coolant injection hole. The hole machining tool according to claim 1, wherein the coolant supply hole and the coolant injection hole communicate with each other through the communication portion.

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