JP4966717B2 - Drilling tool - Google Patents

Description

  The present invention relates to a hole machining tool that is inserted into a prepared hole formed in advance in a workpiece and used to cut an inner wall surface of the prepared hole.

  As this type of drilling tool, for example, as shown in Patent Document 1, a long cylindrical tool body rotated around an axis is cut at the tip end of the tool body and radially outward of the tool body. A so-called reamer is known which is provided with a machining part having a blade. 5 and 6 show an example of a conventional reamer.

  The reamer has a long cylindrical tool body 1 that is rotated around an axis O, and a tip portion of the tool body 1 serves as a processing section 2 that performs cutting. A chip discharge groove 3 opened toward the tip end side of the tool body 1 and the tool body 1 in the radial direction is formed on the outer periphery of the processing portion 2, and a mounting seat 4 is formed on the chip discharge direction T rear side of the chip discharge groove 3. Has been. A flat plate-like insert 6 having a cutting edge 6 </ b> A is seated on the mounting seat 4 with its thickness direction directed to the tool rotation direction T and fixed by a clamp screw 7. A plurality of guide pads 5 are arranged on the outer peripheral surface of the processing portion 2 in the circumferential direction.

  The reamer configured in this way is mounted on the spindle end of the machine tool and rotated around the axis O, fed to the tip side in the direction of the axis O, and inserted into a prepared hole formed in the workpiece. Then, the inner wall surface of the prepared hole is cut by the cutting edge 6A of the insert 6 to form a machining hole having a predetermined inner diameter, and the chips are discharged through the chip discharge groove 3. At the time of this cutting, the inner wall surface of the processing hole and the guide pad 5 slide to prevent a swing of the axis O of the reamer 1 and improve the dimensional accuracy.

In general, during machining, the tip of the reamer is used to reduce the resistance during cutting, slow the progress of wear, extend the life of the cutting edge, and prevent seizure of the inner wall surface of the machining hole and the reamer due to frictional heat. It is necessary to supply coolant. Therefore, a coolant supply hole (not shown) is provided in the tool body 1 in the direction of the axis O, and the coolant is supplied via a coolant discharge hole opened between the vicinity of the tip of the tool body 1 and the coolant supply hole. Is supplied to the cutting edge of the tip.
JP 2002-160124 A

  By the way, in the conventional reamer, the coolant is supplied to the tip portion to be cut, and the cutting edge 6A at the tip portion can reduce the cutting resistance and cool the frictional heat, but can perform good cutting. Since only the coolant supplied toward the cutting edge 6A flows into the sliding contact portion between the inner wall surface of the machining hole and the guide pad 5, a sufficient amount of coolant is obtained particularly when the pilot hole is a through hole. Is not supplied, and the cutting resistance at the time of sliding contact between the inner wall surface of the processing hole and the guide pad 5 is increased. Accordingly, not only the wear of the guide pad 5 is accelerated and the life of the reamer is shortened, but also the heat generated by friction cannot be removed, and when used for a long time, There was a problem that the reamer burned out.

  The present invention has been invented to solve such a problem, and its purpose is to supply a sufficient amount of coolant over the entire machining portion of the drilling tool, so that the drilling tool can be worn out quickly. Accordingly, there is provided a drilling tool that can prevent the service life from being shortened and prevent the drilling of the inner wall surface of the drilled hole and the drilling tool due to frictional heat.

In order to solve the above problems, the present invention proposes the following means.
That is, the hole drilling tool of the present invention has a tool body that rotates about an axis, and a machining part that includes a cutting edge directed toward the tool body tip side and the tool body radial direction outside at the tip of the tool body. Is provided, and a coolant supply hole is inserted into the tool body in the hole machining tool that is inserted into a prepared hole formed in advance in the workpiece and forms a processed hole by cutting the inner wall surface of the prepared hole. An oil groove portion provided in the axial direction and having at least one pair of coolant groove holes with coolant discharge holes communicating with the coolant supply hole is provided on the outer peripheral surface of the processing portion. A guide pad is provided, and the oil groove is also provided in the guide pad .

  When the drilling tool is mounted on the spindle end of the machine tool, coolant is supplied from the machine tool to the coolant supply hole, and the coolant is guided to the oil groove provided on the outer peripheral surface of the machined part through the coolant discharge hole. It is burned. At this time, since the coolant flows along the oil groove portion and is dispersed in at least four directions from the point where the oil groove portions intersect, the coolant can be spread over a wide range of the processed portion.

  Moreover, in the drilling tool which concerns on this invention, the said oil groove part may be provided in the helical form twisted around the said axis line.

  By making the oil groove part into a spiral shape, the oil groove part can be arranged over the whole area in the axial direction and the circumferential direction of the processed part, and the coolant is surely dispersed throughout the processed part from the point where the oil groove part intersects. be able to. Further, since the spiral is twisted around the axis, the coolant is easy to flow along the oil groove portion by the rotation of the drilling tool. Accordingly, it is possible to efficiently spread the coolant over the entire processing portion of the hole drilling tool, and the lubrication effect and the cooling effect can be enhanced.

  Moreover, it is preferable that the twist angle with respect to the said axis line of the said oil groove part exists in the range of 10 degrees-80 degrees.

  When the twist angle is too large, the coolant can be surely spread over the entire processed portion, but it becomes difficult to discharge the coolant that has finished its role and the generated sludge. Furthermore, since the total extension of the oil groove becomes longer, the strength is lowered. On the other hand, if the twist angle is too small, the oil groove portion is close to a straight line, and the coolant and sludge can be easily discharged, but it becomes difficult to spread the coolant over the entire region, and it becomes difficult to obtain a lubrication and cooling effect. In the present invention, by properly setting the twist angle as described above, the coolant and sludge can be reliably discharged while the lubrication and cooling effects are obtained, and the processing can be performed smoothly.

  In the drilling tool according to the present invention, the coolant discharge hole may be opened at a location where the oil groove portion intersects.

  By adopting a configuration in which the coolant is supplied to the location where the oil groove portions intersect, when the coolant is guided to the outer peripheral surface of the processed portion, it can be quickly dispersed in at least four directions along the oil groove portion. Therefore, when coolant is supplied to a portion that does not intersect, one of the coolant dispersed in two directions is dispersed in three directions at the intersection, whereas when supplied to the intersection, Since it is dispersed in at least four directions as it is, it becomes possible to secure more coolant channels in two directions, and even if a large amount of coolant is supplied, it can be distributed without stagnating. Can be further enhanced.

  Moreover, in the drilling tool which concerns on this invention, the opening edge part in the outer peripheral surface of the said process part of the said oil groove part may be chamfered.

  As a result, the boundary between the oil groove and the outer peripheral surface becomes smooth, so that this boundary does not come into contact with the inner wall surface of the machining hole of the work material and damage is caused, thereby causing sludge. Can be maintained high and processing can be performed smoothly.

  According to the present invention, the coolant can be reliably supplied to the outer peripheral surface of the processed portion, and therefore, the lubrication action of the coolant prevents wear of the processed portion due to friction between the inner wall surface of the processed hole and the outer peripheral surface of the hole processing tool. The service life of the drilling tool can be extended, and the frictional heat can be easily removed by the cooling action, so that the inner wall surface of the drilled hole and the drilling tool can be prevented from being seized.

  Hereinafter, a reamer which is an embodiment of a drilling tool of the present invention will be described in detail with reference to FIGS. FIG. 1A is a side view of a reamer according to an embodiment of the present invention, FIG. 1B is a side view as seen from the direction b in FIG. 1A, and FIG. FIG. 2 is a partially enlarged view of the reamer shown in FIG. 1A, FIG. 3 is a front view of the reamer according to the embodiment of the present invention, and FIG. 4 is a cross section taken along line XX in FIG. FIG.

  The reamer shown in FIGS. 1 to 3 has a multi-stage cylindrical tool body 10 that is rotated in the tool rotation direction T around an axis O, and the tip side (the lower side in FIG. 1) of the tool body 10 is approximately. A cylindrical processing portion 11 is formed, and a substantially cylindrical shank portion 12 having a larger diameter than the processing portion 11 is formed on the rear end side (the upper side in FIG. 1) of the tool body 10. The processing part 11 and the shank part 12 are integrally formed via a neck part 13 having a substantially cylindrical shape having a smaller diameter than these two parts.

  In addition, a coolant supply hole 14 that opens to the rear end side (upper side in FIG. 1) of the shank portion 12 and extends to the vicinity of the tip of the processing portion 11 along the axis O is provided in the tool body 10. 13 is provided.

  On the outer peripheral surface of the processing portion 11, a chip discharge groove 15 having a shape obtained by cutting the processing portion 11 into a substantially L shape in a cross section perpendicular to the axis O extends so as to extend from the front end to the rear end of the processing portion 11. Is provided. A mounting seat 16 for mounting the cutting edge tip 18 is formed on the wall surface facing the front side in the tool rotation direction T of the tip portion of the chip discharge groove 15 so as to be recessed by one step from the wall surface. A coolant discharge hole 17 for a cutting blade that extends from the coolant supply hole 14 toward the outer side in the radial direction of the tool main body is opened in the wall surface facing the rear side of the tool.

  The cutting edge tip 18 attached to the attachment seat 16 of the processed portion 11 has a flat shape and has a base portion 25 formed of a hard material such as cemented carbide. The cutting edge tip 18 includes a cutting edge portion 21 having a biting cutting edge 19 toward the outer peripheral side of the tip of the processing portion 11 and an outer peripheral cutting edge 20 toward the radially outer side. The cutting edge portion 21 is composed of a diamond sintered body that is integrally sintered with the base portion 25, and the biting cutting edge 19 protrudes from the front end surface of the tool body 10, and the outer peripheral cutting edge 20 is arranged so as to protrude to the outer peripheral side of the tool body 10. When the cutting blade tip 18 is attached to the attachment seat, it is fixed by brazing in the present embodiment, but it may be detachably attached by screwing as in Patent Document 1.

  A plurality of guide pads 24 having a cylindrical outer peripheral surface centering on the axis O and extending substantially parallel to the axis O are provided on the outer periphery from the intermediate portion in the axis O direction to the tip end portion of the processing portion 11. It has been. In the present embodiment, the guide pad 24 is chamfered on the outer peripheral surface of the processing portion 11 except for the portion where the guide pad 24 is formed, and is then subjected to cylindrical polishing around the axis O on the processing portion 11. This is formed by avoiding the chip discharge groove 15 of the processed portion 11 and spaced in the circumferential direction. Here, in the cross section with respect to the axis O, the distance between the outer peripheral surface of the guide pad 24 and the axis O is set to be slightly smaller than the distance between the outer peripheral cutting edge 20 of the cutting edge portion 21 and the axis O. The rear end side of the processing portion 11 provided with the guide pad 24 has a diameter larger than that of the neck portion 13 and is reduced by one step from the front end side.

  Then, at least a pair of oil groove portions 22 are provided on the outer peripheral surface of the processed portion 11 so as to cross each other. The oil groove portion 22 is a concave groove formed on the outer peripheral surface of the processed portion 11, and the width and depth thereof are sufficiently smaller than the chip discharge groove 15, for example. The oil groove portion 22 is disposed in a spiral shape extending around the entire circumference from the front end portion to the rear end portion of the processed portion 11 while twisting around the axis O, and the twist angle of the oil groove portion 22 with respect to the axis O θ is set within a range of 10 ° to 80 °. Moreover, although the cross section of the oil groove part 22 is semicircular in this embodiment, it may be V-shaped, and the opening edge part opened to the outer peripheral surface of the process part 11 of the oil groove part 22 is chamfered. In addition, the end of the cross section of the oil groove portion 22 is inclined so as to intersect the groove wall surface of the oil groove portion 22 and the outer peripheral surface of the processed portion 11 at an obtuse angle.

  Further, the spiral oil groove portion 22 includes two oil groove portions 22 provided in parallel at a constant interval in the same twist direction, and two more so that the twist directions of the spiral are different from each other. The oil groove portions 22 are provided at intervals equal to the interval, and therefore, a plurality of locations where the oil groove portions 22 intersect with each other are provided on the outer peripheral surface of the processed portion 11. The oil groove portion 22 also intersects with the guide pad 24.

  The oil groove 22 is provided with a groove coolant discharge hole 23 extending in the radial direction from the coolant supply hole 14 to the outer periphery of the processing portion 11. It is comprised so that it may open to the location where different spiral oil groove parts 22 cross | intersect. The groove coolant discharge hole 23 is desirably provided so as to avoid the position of the guide pad 24.

  Hereinafter, cutting using a reamer, which is an embodiment of the drilling tool of the present invention, will be described. The reamer of the present embodiment is mounted on a machine tool and rotated around the axis O in the tool rotation direction T, and the processing portion 11 is inserted into a prepared hole formed in advance in the workpiece from the tip side. At this time, the inner wall surface of the prepared hole is cut by the biting cutting edge 19 with respect to the reaming direction and the outer peripheral cutting edge 20 with respect to the outer peripheral direction to be finished into a processing hole having a predetermined inner diameter. Further, chips generated during the cutting are sent from the front end of the processed portion 11 to the rear end side and discharged by the chip discharge groove 15.

  In addition, a guide pad 24 is provided on the outer periphery of the processed portion 11, and the distance between the outer peripheral surface of the guide pad 24 and the axis O is more than the distance between the outer peripheral cutting edge 20 of the cutting blade 21 and the axis O. Since it is slightly small, the guide pad 24 and the inner wall surface of the machined hole are in sliding contact with each other during the cutting process. Thereby, it can suppress that it vibrates when a reamer rotates in a process hole at high speed, and can process a process hole with high precision.

  In this cutting process, the coolant is supplied from the machine tool to the coolant supply hole 14, and the coolant is supplied to the cutting edge portion 21 through the cutting blade coolant discharge hole 17 opened in the chip discharge groove. By supplying this coolant, it is possible to improve the lubrication of the cutting process of the cutting edge part 21 to prevent wear and to prolong the life of the cutting edge part 21, to cool the frictional heat, and to cut the machining hole and the cutting edge. Burn-in of the part 21 can be avoided.

  In general, the coolant is liquid and is supplied to the reamer. However, in the present embodiment, a very small amount of coolant is made into a mist form and is sent to the coolant supply hole 14 by compressed air. It is good. As a result, while obtaining the same cooling effect as liquid coolant, a small amount of coolant is sufficient compared to liquid coolant, so the equipment required for coolant recovery and processing can be simplified, and costs can be greatly reduced. it can.

  And in this embodiment, it is set as the structure which provided the oil groove part 22 in the outer periphery of the process part 11, and provided in this oil groove part 22 the groove | channel coolant discharge hole 23 connected to the coolant supply hole 14 so that it may mutually cross | intersect. Therefore, during the cutting process, the coolant is also supplied to the outer periphery of the processed part 11 through the groove coolant discharge hole 23. Furthermore, since the oil grooves 22 are dispersed in four directions from the point where they intersect, the coolant can be spread over a wide range of the processed part 11. Accordingly, the lubricating effect can be obtained reliably and efficiently even at the sliding position between the guide pad 24 and the inner wall surface, and the frictional heat can be removed.

Furthermore, since the oil groove part 22 is helically arranged over the entire periphery of the processing part 11, the coolant flows along the spiral and spreads over the entire area, and is dispersed in four directions from the point where the oil groove part 22 intersects. . Further, since the spiral is twisted around the axis O, the coolant can easily flow along the oil groove portion 22 along with the rotation of the reamer, and can reach the entire processing portion 11. Accordingly, it is possible to efficiently distribute the coolant over the entire area of the reamer processed portion 11 and enhance the lubrication effect and the cooling effect.

  On the other hand, in the reamer according to the present embodiment, since the coolant coolant discharge hole 23 is opened at a location where the oil groove portion 22 intersects and the coolant is supplied, oil is generated when the coolant is guided to the outer peripheral surface of the processing portion 11. It disperses quickly in four directions along the groove 22. Therefore, when coolant is supplied to a portion that does not intersect, one of the coolant dispersed in two directions branches in three directions at the intersection, whereas when supplied to the intersection, Since it is dispersed in four directions as it is, it becomes possible to secure a coolant flow path in two more directions, and even if a large amount of coolant is supplied, it can be smoothly spread over the entire processing portion 11 without stagnating. The effect and the cooling effect can be further enhanced.

  In addition, when the helical twist angle θ of the oil groove 22 is too large, the coolant can be surely spread over the entire processing portion, but it becomes difficult to discharge the coolant that has finished its role and the generated sludge. End up. Furthermore, since the total extension of the oil groove becomes longer, the strength is lowered. On the other hand, when the torsion angle θ is too small, the oil groove portion 22 is close to a straight line, and it becomes easy to discharge the coolant and sludge, but it becomes difficult to spread the coolant over the entire region, and it becomes difficult to obtain a lubrication and cooling effect. . In the present embodiment, as described above, the twist angle θ is set to an appropriate value of 10 ° to 80 °, so that coolant and sludge can be reliably discharged while obtaining a lubrication and cooling effect. Can be processed.

  Moreover, since the opening edge part opened to the outer peripheral surface of the process part 11 of the oil groove part 22 is chamfered, even when the outer peripheral surface of the process part 11 contacts the inner wall face of the to-be-cut object in the case of a process The edge portion does not damage the inner peripheral wall and sludge is not generated thereby, so that the processing accuracy can be maintained high and the processing can be performed smoothly.

  From the above, according to the reamer according to the present embodiment, a sufficient amount of coolant can be supplied also to the outer peripheral surface of the processing portion 11, so that the inner wall surface of the processing hole and the sliding portion of the guide pad 24 are lubricated. It is possible to prevent wear of the machined portion 11 due to the friction of the workpiece, to prolong the life of the reamer, to easily remove the frictional heat by the cooling action, and to prevent the inner wall surface of the machining hole and the reamer from being seized. .

  As mentioned above, although the reamer which is embodiment of this invention was demonstrated, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention. For example, in the present embodiment, the oil groove portion 22 is configured by a total of four spirals, but if it is provided so that at least a pair of oil groove portions 22 intersect, the number of oil groove portions 22 may be four or less, or more than that. The oil groove part 22 which consists of a spiral may be sufficient. Further, the chamfering provided on the opening edge portion that opens to the outer peripheral surface of the processed portion 11 of the oil groove portion 22 may have a cross section formed in an arc shape.

It is a side view of the reamer which is an embodiment of the present invention. It is the elements on larger scale of the reamer shown to Fig.1 (a). It is a front view of the reamer which is an embodiment of the present invention. It is XX sectional drawing of the reamer shown to Fig.1 (a). It is an expanded partial sectional view of the conventional reamer tip. FIG. 6 is a YY sectional view in FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tool main body 11 Processing part 12 Shank part 13 Neck part 14 Coolant supply hole 15 Chip discharge groove 16 Mounting seat 17 Coolant discharge hole for cutting blade 18 Cutting edge tip 19 Cutting edge 20 Cutting edge part 21 Cutting edge part 22 Oil groove part 23 Coolant discharge hole for groove 24 Guide pad 25 Base O Axis T Rotation direction

Claims (5)

A tool body having a tool body rotated about an axis is provided, and a processing portion having cutting edges directed to the tool body tip side and the tool body radial direction outside is provided at the tip of the tool body, and formed in advance on a workpiece. In a hole machining tool that is inserted into the prepared pilot hole and cuts the inner wall surface of the pilot hole to form a processed hole.
A coolant supply hole is provided in the axial direction inside the tool body,
On the outer peripheral surface of the processed portion, an oil groove portion having a coolant discharge hole communicating with the coolant supply hole is provided so as to intersect at least a pair with each other ,
A drilling tool characterized in that a guide pad is provided on an outer periphery of the processing portion, and the oil groove portion is also provided in the guide pad .   The drilling tool according to claim 1, wherein the oil groove portion is provided in a spiral shape twisted around the axis.   The drilling tool according to claim 2, wherein a twist angle of the oil groove portion with respect to the axis is in a range of 10 ° to 80 °.   The drilling tool according to any one of claims 1 to 3, wherein the coolant discharge hole is opened at a location where the oil groove portions intersect. The drilling tool according to any one of claims 1 to 4, wherein an opening edge portion of the outer peripheral surface of the processing portion of the oil groove portion is chamfered.

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