JP2009078330A - Rotary boring tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary boring tool which can smoothly discharge cutting chips from a hole currently bored. <P>SOLUTION: A drill 1 is the rotary boring tool which has a tip 7 of a diamond sintered body mounted on a blade portion at a front edge thereof, and carries out bore machining in a workpiece in front thereof while receiving feeding of cutting water from a rear edge via an oil hole 11 inside a body 5. The drill 1 has rearward blasting holes 19a, 19b formed in the body 5, for injecting the cutting water in the oil hole 11 to the outside of the body 5 in a diagonally rearward direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary drilling tool in which a tip of a diamond sintered body is attached to a blade portion at a front end, and a hole is formed in a front workpiece while receiving coolant from an oil hole inside a body from the rear end.

Conventionally, many machines using this type of tool are provided with a mechanism for supplying coolant to the machining point in order to cool the machining point where the workpiece and the tool are in contact with each other and to wash away the chips. For example, an apparatus described in Patent Document 1 below is a grinding apparatus that grinds a workpiece with a rotating grinding wheel, and includes a coolant supply device that ejects coolant toward a grinding wheel portion of the rotating grinding wheel. Then, it has been proposed that the coolant is smoothly supplied to the grindstone while the coolant is jetted in various directions with this coolant supply device. In addition, the drill described in Patent Document 2 below is provided with an oil hole that supplies coolant to the inside of the drill body, and the coolant supplied from the machine side through the oil hole is ejected from an opening near the edge of the drill. The
JP 2006-305675 A JP 2005-138203 A

  However, as in Patent Document 1, in the method of supplying the coolant from the outside of the tool toward the tool, there may be a case where sufficient coolant does not reach the processing point and the removal of chips may not be sufficient. On the other hand, the drill described in Patent Document 2 below can supply coolant directly to the cutting edge in the hole during machining of the workpiece by ejecting the coolant from the opening in the vicinity of the cutting edge. However, even in this method, if the chips generated at the bottom of the hole being machined are not smoothly discharged from the entrance of the machined hole, the flute groove is clogged with chips, causing breakage of the drill, There is a risk that trouble may occur in which chips enter the narrow space between the processing surfaces and damage to the processing surfaces occurs. Therefore, in this type of drilling tool, further smooth discharge of chips is desired.

  Then, an object of this invention is to provide the rotary drilling tool which can discharge a chip | tip smoothly from the hole in process.

  The rotary drilling tool of the present invention is a rotary drilling tool in which a tip of a diamond sintered body is attached to the blade portion at the front end, and the front workpiece is drilled while receiving coolant supplied through an oil hole in the body. The rear injection hole is provided on the body and injects the coolant of the oil hole obliquely rearward to the outside of the body.

  According to this rotary drilling tool, when the tool enters while making a hole in the front workpiece, the coolant is ejected obliquely rearward from the rear ejection hole in the hole being processed. This oblique rearward jetting promotes the coolant flow toward the rear in the hole being processed, and chips generated in the hole being processed are transferred from the inlet of the hole by the backward flow of the coolant. It is discharged smoothly.

  Further, it is preferable that the rear ejection hole is provided in a portion of the body that is plunged into the workpiece during drilling. With this configuration, a coolant flow toward the rear is reliably generated in the hole being processed.

  Moreover, it is preferable that a back ejection hole is provided in the flute groove formed in the body. According to this configuration, since the coolant ejected from the rear ejection hole flows rearward in the flute groove, the flow of chips discharged through the flute groove can be further promoted.

  Moreover, you may further provide the front injection hole which is provided in the body in the position ahead of the rear injection hole and injects the coolant from the oil hole to the outside of the body toward the front. With this configuration, coolant can also be supplied to the cutting edge, and chips can flow more smoothly.

  According to the rotary drilling tool of the present invention, chips can be smoothly discharged from the hole being processed.

  Hereinafter, a preferred embodiment of a rotary drilling tool according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
A drill 1 shown in FIGS. 1 and 2 is a rotary cutting tool used for drilling a metal workpiece. The drill 1 includes a shank 3 held by a chuck of a machine and a body 5 connected to the front of the shank 3. The drill 1 advances forward (in the direction of arrow Z) while rotating around the rotation axis A with the shank 3 held by the chuck of the machine. Two diamond sintered body chips 7 are attached to the blade portion 2 at the front end of the drill 1, and the body 5 is provided with two spiral flute grooves 5a and 5b.

  An oil hole 11 through which water (cutting water) supplied from the rear end passes is formed in a straight shape along the rotation axis A inside the shank 3 and the body 5. The tip of the oil hole 11 is connected to branch channels 13a and 13b that are bifurcated and extend obliquely forward. On the surface of the body 5, two front ejection holes 15 a and 15 b are formed in the vicinity of the blade portion 2 in the flute groove 5 a to eject the cutting water that has passed through the branch flow paths 13 a and 13 b obliquely forward.

  The oil hole 11 is connected to two branch channels 17a and 17b that branch behind and extend obliquely rearward from the branch channels 13a and 13b. And on the surface of the outer periphery of the body 5, rear ejection holes 19a and 19b for ejecting cutting water obliquely rearward through the branch channels 17a and 17b are provided in the flute grooves 5a and 5b, respectively. An angle α formed by the direction in which the cutting water P is ejected from the rear ejection holes 19a and 19b and the traveling direction Z of the drill 1 is set to about 150 °. Further, the branch flow paths 13a, 13b, 17a, 17b are all formed to have the same hole diameter, and the discharge forces of the cutting water from the front ejection holes 15a, 15b and the rear ejection holes 19a, 19b are all equal.

  The diameter of the oil hole 11 is appropriately determined depending on the tool diameter, web thickness, and strength of the drill 1. For example, in general, when the tool diameter of the drill 1 is φ10 to 30, the diameter of the oil hole 11 is often set to φ3. At this time, the hole diameters of the branch channels 13a, 13b, 17a, and 17b are set to, for example, φ1.5 (in the case of a carbide shank) or φ2 (in the case of a steel-based shank). When the tool diameter of the drill 1 is φ5 to 10, for example, the diameter of the oil hole 11 is set to φ2, and the hole diameters of the branch channels 13a, 13b, 17a, and 17b are set to φ1.2.

  Next, with reference to FIG. 3, the drilling process of the workpiece | work W using this drill 1 is demonstrated. As shown in FIG. 3, in drilling, the drill 1 attached to the chuck of the machine rotates and advances downward while cutting the workpiece W. Then, a predetermined entry length portion 5d of a predetermined length enters the workpiece W from the front end of the body 5, and a set hole H extending in the vertical direction is formed in the workpiece W. The chips generated inside the hole H being processed rise in the flute grooves 5a and 5b of the rotating drill 1 and are discharged from the inlet H1 of the hole H being processed to the surface of the workpiece W. Further, during machining, cutting water is supplied to the drill 1 from the machine side through the oil hole 11 in order to cool the cutting point and discharge chips. A part of this cutting water is ejected forward from the front ejection holes 15a and 15b through the branch flow paths 13a and 13b, efficiently cooling the blade part 2 and the cutting part, and flowing chips generated in the cutting part. .

  Further, in this drill 1, the above-described branch flow channels 17 a and 17 b and the rear ejection holes 19 a and 19 b are provided in the planned entry portion 5 d that enters the workpiece W, so that the cutting water from the oil hole 11 is provided. A part is ejected obliquely upward from the rear ejection holes 19a, 19b in the hole H. By such an ejection of the cutting water P obliquely upward, the upward flow of the cutting water is promoted in the flute grooves 5a and 5b of the planned entry portion 5d. The chips are smoothly raised in the flute grooves 5a and 5b while being swept away by the upward cutting water, and are smoothly discharged from the inlet H1 of the hole H being processed. Therefore, according to the drill 1, troubles such as breakage of the drill due to defective discharge of chips and damage to the inner wall surface of the hole H can be reduced.

  Further, in this drill 1, since the rear ejection holes 19a, 19b are provided in the flute grooves 5a, 5b, the cutting water P is separated from the wall surface of the flute grooves 5a, 5b and the inner wall surface of the hole H being processed. It is supplied with an upward flow to the chip discharge path formed surrounded by Therefore, the upward flow of cutting water is surely promoted in the chip discharge path, and chip discharge can be surely promoted.

  In addition, regarding the setting of the angle α (see FIG. 1) regarding the injection direction of the cutting water P from the rear ejection holes 19a and 19b, the angle α is not limited to about 150 °, and the angle α may slightly exceed 90 °. For example, in the hole H being processed, the effect of promoting the flow of cutting water toward the inlet H1 can be achieved. In particular, when the angle α is 140 ° or more, the cutting water can smoothly flow in the hole H toward the inlet H1. On the other hand, when the angle α exceeds 155 °, it is difficult to produce the branch channels 17a and 17b when the drill 1 is manufactured. Therefore, the angle α is particularly preferably set to 140 to 155 °. Further, in order to cause the above-described action of promoting the flow of cutting water to occur at an early stage after the start of drilling the hole H, the rear ejection holes 19a and 19b should be provided as close to the tip of the body 5 as possible. preferable.

(Second Embodiment)
A drill 201 shown in FIG. 4 is provided with a pair of rear ejection holes 219a and 219b in addition to the configuration of the drill 1 described above. The rear ejection holes 219a and 219b are provided in the flute grooves 5a and 5b in the planned entry portion 5d, and are located behind the rear ejection holes 19a and 19b, and a part of the cutting water supplied through the oil hole 11 is used. Spouts diagonally backward. With this configuration, the upward flow of cutting water is further promoted in the flute grooves 5a and 5b of the planned entry portion 5d. Further, a rear ejection hole may be further added behind the rear ejection holes 219a and 219b. In addition, in this drill 201, about the structure same or equivalent to the above-mentioned drill 1, the same code | symbol is attached | subjected to drawing and the description is abbreviate | omitted.

(Third embodiment)
For example, in the case of a long tool having a tool total length of 300 mm, a stepped oil hole 311 may be provided as a drill 301 shown in FIG. That is, the oil hole 311 of the drill 301 is composed of two parts having different diameters with the central stepped part 311c as a boundary, such as a hole front part 311a of φ3 and a hole rear part 311b of φ4. In this case, the rear branch channels 17a and 17b are not separated from the φ4 hole rear portion 311b, but are branched from the φ3 hole front portion 311a. With this configuration, the discharge forces of the cutting water P in the front injection holes 15a and 15b and the rear injection holes 19a and 19b are all equal. In addition, in this drill 301, about the structure same or equivalent to the above-mentioned drill 1, the same code | symbol is attached | subjected to drawing, and the description is abbreviate | omitted.

(Fourth embodiment)
A drill 401 shown in FIG. 6 is of a type in which two oil holes 411 a and 411 b extending in a spiral shape are provided inside the shank 3 and the body 5. Then, the cutting water supplied from the machine through the oil holes 411a and 411b is ejected forward from the front ejection ports 415a and 415b provided on the flank face of the blade portion. In the drill 401, two to four rear ejection holes 419 for ejecting the cutting water branched from the oil holes 411a and 411b obliquely rearward are provided in the flute grooves 5a and 5b. Thus, also in the drill 401 provided with the spiral oil holes 411a and 411b, by providing the rear ejection hole 419 for ejecting the cutting water P from the oil hole obliquely rearward, the same action as the above-described drill 1 is achieved. An effect can be obtained. In addition, in this drill 401, about the structure same or equivalent to the above-mentioned drill 1, the same code | symbol is attached | subjected to drawing, and the description is abbreviate | omitted.

(Fifth embodiment)
A reamer 501 shown in FIG. 7 is of a type in which an oil hole 511 extending straight is provided inside the shank 3 and the body 5. Then, the cutting water supplied through the oil hole 511 is ejected obliquely forward from the front ejection holes 515a and 515b provided in the vicinity of the blade portion. In the reamer 501, rear ejection holes 519a and 519b for ejecting the cutting water P branched from the oil hole 511 obliquely rearward are provided in the flute grooves 5a and 5b. Thus, also in the reamer 501 provided with the oil hole, the same operation effect as the above-described drill 1 is obtained by providing the rear ejection holes 519a and 519b that eject the cutting water P from the oil hole 511 obliquely rearward. be able to. In the reamer 501, the same or equivalent components as those of the drill 1 described above are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

(Sixth embodiment)
A reamer 601 shown in FIG. 8 is provided with a pair of rear ejection holes 620a and 620b in addition to the configuration of the reamer 501 described above. The rear ejection holes 620a and 620b are provided in the flute grooves 5a and 5b in the planned entry portion 5d and are located behind the rear ejection holes 519a and 519b, and the cutting water P supplied through the oil hole 511 is obliquely rearward. Erupts towards With this configuration, in the flute grooves 5a and 5b of the planned entry portion 5d, the flow of the cutting water upward in the hole being processed is further promoted. Further, a rear ejection hole may be further added behind the rear ejection holes 620a and 620b. In the reamer 601, the same or equivalent components as those of the reamer 501 described above are denoted by the same reference numerals, and description thereof is omitted.

(Seventh embodiment)
The reamer 701 shown in FIGS. 9 and 10 is also called a stepped reamer in which a diamond sintered body chip 707 as a cutting edge is attached in two stages, and an oil hole 711 extending straightly inside the shank and the body is provided. It is of the type. In this reamer 701, a part of the cutting water supplied through the oil hole 711 is ejected forward from four front ejection holes 715 provided in the vicinity of the first-stage (front) blade portion 702. During cutting, the cutting water efficiently cools the blade portion 702 and the cutting portion and causes chips generated in the cutting portion to flow. Further, in this reamer 701, four rear ejection holes 719 through which the cutting water P branched from the oil hole 711 is ejected obliquely rearward are provided in the four land portions 721.

  In the case of processing the vertically extending stop hole with the reamer 701 inserted from above, a part of the cutting water from the oil hole 711 is directed obliquely upward from the rear ejection hole 719 in the hole being processed. Is ejected. By such an ejection of the obliquely upward cutting water P, the upward flow of the cutting water is promoted in the hole being processed. Then, the chips rise smoothly in the hole while being swept away by the upward cutting water, and are smoothly discharged from the inlet of the hole. Therefore, according to the reamer 701, troubles such as breakage of the drill due to defective chip discharge and damage to the inner wall surface of the hole can be reduced. As described above, even in the reamer 701 in which the rear ejection hole 719 is provided in the land portion 721, the same operational effect as that of the above-described reamer 501 can be obtained. Note that in this reamer 701, the same or equivalent components as those of the above-described reamer 501 are denoted by the same reference numerals, and description thereof is omitted.

(Eighth embodiment)
A stepped reamer 801 shown in FIG. 11 includes a second front ejection hole 816 that ejects cutting water forward toward the second stage blade 802 in addition to the above-described reamer 701, and includes a rear ejection hole 719. Furthermore, the rear back ejection hole 820 located behind is provided. By this second front ejection hole 816, the second stage blade portion 802 and the cutting portion are efficiently cooled during processing. Further, the addition of the rear ejection hole 820 further promotes the flow of cutting water toward the inlet of the hole being processed. Further, a rear ejection hole may be further added behind the rear ejection hole 820. In addition, in this reamer 801, about the structure same or equivalent to the above-mentioned reamer 701, the same code | symbol is attached | subjected to drawing, and the description is abbreviate | omitted.

  The present invention is not limited to the first to eighth embodiments described above. For example, in each of the above-described embodiments, the injection direction P of the cutting water from the rear injection hole is set to form an angle of about 150 ° with respect to the traveling direction of the tool as described above. You may change suitably in the range in which the said angle slightly exceeds 90 degrees. In the embodiment, water is used as the coolant. However, as the coolant, oil or air may be used. Further, in the processing of the stop hole as shown in each of the above-described embodiments, since the chips can be discharged only to the inlet side of the hole, the present invention is particularly suitable for drills and reamers that process the stop hole. Although preferably applied, the present invention is also applicable to a tool for machining a through hole.

It is a side view which shows the drill which is 1st Embodiment of the rotary drilling tool which concerns on this invention. It is a bottom view of the drill of FIG. It is a partial sectional view showing a drill and a workpiece during drilling. In the drill which is 2nd Embodiment of the rotary drilling tool which concerns on this invention, it is a figure which shows arrangement | positioning of an oil hole, a branch flow path, and an ejection hole. It is a side view which shows the drill which is 3rd Embodiment of the rotary drilling tool which concerns on this invention. It is a side view which shows the drill which is 4th Embodiment of the rotary drilling tool which concerns on this invention. It is a side view which shows the reamer which is 5th Embodiment of the rotary drilling tool which concerns on this invention. It is a figure which shows arrangement | positioning of an oil hole, a branch flow path, and an ejection hole in the reamer which is 6th Embodiment of the rotary drilling tool which concerns on this invention. It is a fragmentary sectional view which expands and shows a front-end | tip part about the reamer which is 7th Embodiment of the rotary drilling tool which concerns on this invention. FIG. 10 is a bottom view of the reamer of FIG. 9. It is a figure which shows arrangement | positioning of an oil hole, a branch flow path, and an ejection hole in the reamer which is 8th Embodiment of the rotary drilling tool which concerns on this invention.

Explanation of symbols

  1, 201, 301, 401 ... drill (rotary drilling tool), 501, 601, 701, 801 ... reamer (rotary drilling tool), 2 ... blade, 5 ... body, 5a, 5b ... flute groove, 5d ... scheduled to enter Part: 7 ... Diamond sintered body chip, 11 ... Oil hole, 15a, 15b, 415a, 415b, 515a, 515b, 715, 816 ... Front injection hole, 19a, 19b, 219a, 219b, 419, 519a, 519b, 620a , 620b, 719, 820 ... rear ejection holes, 49 ..., P ... cutting water, W ... work.

Claims (4)

In a rotary drilling tool in which a tip of a diamond sintered body is attached to the blade part at the front end, and drilling processing is performed on the front work while receiving coolant from the oil hole inside the body from the rear end,
A rotary drilling tool provided with a rear injection hole provided on the body and for discharging the coolant of the oil hole obliquely rearward to the outside of the body.   2. The rotary drilling tool according to claim 1, wherein the rear ejection hole is provided in a portion of the body that is inserted into the workpiece during drilling.   The rotary drilling tool according to claim 1 or 2, wherein the rear ejection hole is provided in a flute groove formed in the body.   The front injection hole which is provided in the body at a position ahead of the rear injection hole and which injects coolant from the oil hole to the outside of the body toward the front is further provided. 4. The rotary drilling tool according to any one of 3 above.

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