JP2018192610A - Body - Google Patents

Abstract

To provide a body enabling reduction in the rigidity thereof to be suppressed, while having a plurality of discharge grooves.SOLUTION: A body 1 comprises a first chip seat 21, a second chip seat 22 and a third chip seat 23 which are spaced in the circumferential direction of an axis C. One end 11a of a first discharge groove 11 is formed in a region corresponding to the first chip seat 21 and the second chip seat 22. One end 12a of a second discharge groove 12 is formed in a region corresponding to the third chip seat 23. The second discharge groove 12 spirally stretches, and the other end 12b thereof is connected to the middle of the first discharge groove 11 in an outer circumferential surface 1c of the body 1. The first discharge groove 11 stretches along the axis C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a body of a drilling tool.

  A drilling tool, which is called a gun drill or the like and used for deep hole machining, has become widespread. Patent Document 1 discloses a drilling tool in which a cutting edge is formed integrally with a body. Patent Document 2 discloses a drilling tool in which a cutting insert in which a cutting edge is formed is detachably attached to a body.

  These drilling tools form a hole by rotating a body about a predetermined axis and cutting a work material with a cutting edge. Chips generated by the cutting edge are guided by discharge grooves formed on the outer peripheral surface of the body and discharged from the holes.

JP 2011-245622 A JP 2006-192553 A

  In order to increase the diameter of the hole formed in the work material, it is necessary to increase the length of the cutting edge. However, when the length of the cutting edge is increased, the cutting resistance acting on the cutting edge is increased accordingly. As a result, the cutting edge may be lost or the performance required for the actuator that rotates the body may increase, leading to an increase in manufacturing cost.

  As a method for coping with such an increase in cutting resistance, a method of cutting a workpiece with a plurality of cutting edges is known. The cutting edges are provided at intervals in the circumferential direction of the body shaft. According to this method, it is possible to reduce the cutting resistance acting on one cutting edge.

  However, when cutting a workpiece with a plurality of cutting edges, it is necessary to form a plurality of discharge grooves corresponding to each cutting edge in the body. As a result, the cross-sectional area of the body is reduced, and there is a possibility that the rigidity of the body is reduced. The decrease in the rigidity of the body causes various inconveniences such as a decrease in the dimensional accuracy of the hole.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a body that can suppress a decrease in rigidity while having a plurality of discharge grooves.

  In order to solve the above-mentioned problem, a body according to the present invention is provided with a cutting edge that cuts a work material provided at a distal end portion of a body extending along a predetermined axis and spaced from each other in the circumferential direction of the axis. One end is formed at a portion corresponding to the first placement portion of the outer peripheral surface of the body and the first placement portion and the second placement portion, and extends from the distal end side of the body toward the proximal end side. In addition, one end is formed in a portion corresponding to the second placement portion of the first discharge groove that guides the chips generated by the cutting blade placed in the first placement portion, and the outer peripheral surface of the body, And a second discharge groove that extends from the distal end side toward the proximal end side and guides chips generated by the cutting blade arranged in the second arrangement portion. The second discharge groove extends in a spiral shape, and the other end is connected to the middle of the first discharge groove on the outer peripheral surface of the body. The first discharge groove extends along the axis.

  Here, the thing of a various form can be employ | adopted for the cutting blade arrange | positioned at a 1st arrangement | positioning part and a 2nd arrangement | positioning part. For example, the cutting edge may be formed integrally with the body. In this case, a portion of the body where the cutting edge is formed corresponds to the first placement portion or the second placement portion.

  Further, the cutting edge may be formed on a cutting insert separate from the body, and the cutting insert may be attached to the body. In this case, a portion of the body to which the cutting insert is attached corresponds to the first placement portion and the second placement portion.

  According to the said structure, the chip | tip produced | generated by the cutting blade arrange | positioned at the 2nd arrangement | positioning part is guided by the 2nd discharge groove, and enters into the 1st discharge groove. The chips are guided by the first discharge groove together with the chips generated by the cutting blade arranged in the first arrangement portion, and are discharged from the hole.

  That is, according to the above configuration, the first disposing portion and the second disposing groove are not formed on the base end side from the portion where the first discharging groove and the second discharging groove are connected in the body. Chips generated by the cutting blades arranged in each of the two arrangement parts can be discharged out of the hole. Thereby, it becomes possible to suppress the fall of the rigidity of a body.

  Further, the other end of the second discharge groove is connected to the middle of the first discharge groove on the outer peripheral surface of the body. As a result, it is possible to suppress clogging of chips in the second discharge groove as compared with a configuration in which the second discharge groove passes through the inside of the body and is connected to the middle of the first discharge groove. Further, it is possible to easily form a coolant channel or the like in the body.

  Here, a temporary body in which the entire first discharge groove extends spirally will be considered. In this case, when the body is arranged so that the shaft is along the horizontal direction, it may be difficult to discharge the chips. That is, when the first discharge groove extends spirally on the outer peripheral surface of the body and the body is arranged so that the axis is along the horizontal direction, the chips guided by the first discharge groove are Turn while reciprocating. Thereby, there exists a possibility that the smooth guidance of the chip | tip by the 1st discharge groove and its discharge may be inhibited.

  Therefore, in the above configuration, the first discharge groove extends along the axis, and the second discharge groove extends in a spiral shape.

  According to this configuration, even when the body is arranged so that the axis is along the horizontal direction, the chips are guided in the horizontal direction by the first discharge groove. As a result, involuntary turning of the chips can be suppressed, and the chips can be smoothly guided and discharged out of the hole.

  When the body is viewed from a direction orthogonal to the axis, the angle formed between the extending direction of the first discharge groove and the axis may be smaller than the angle formed between the extending direction of the second discharge groove and the axis.

  According to this configuration, it is possible to extend the second discharge groove so as to gradually approach the first discharge groove toward the base end side of the body, and connect the second discharge groove to the first discharge groove. Become.

  The 2nd discharge groove may have a straight part extended along an axis from the 2nd arrangement part, and a spiral part connected to the end of a straight part, and extending in the shape of a spiral.

  According to this configuration, a relatively wide space can be secured in a portion between the first discharge groove and the straight line portion of the second discharge groove on the outer peripheral surface of the body. This makes it possible to use the space for attaching the guide pad.

  By the way, when cutting while discharging coolant into the hole of the work material, the discharged coolant flows into the discharge groove mainly from the front end side of the body. By guiding the coolant through the discharge groove and flushing away the chips, the chips can be discharged from the holes and a deeper hole can be formed in the work material.

  In the case of a body in which a plurality of discharge grooves are formed, the discharged coolant flows into each discharge groove. In this case, the flow rate of the coolant flowing into each discharge groove may be smaller than in the form in which a single discharge groove is formed. As a result, each discharge groove may not be able to smoothly guide chips. In particular, since the discharge groove to which the other discharge groove is connected needs to guide a large amount of coolant after joining, a decrease in the flow rate of the coolant flowing into the discharge groove may cause clogging of chips. There is.

  Therefore, the first discharge groove may include a spiral portion that extends spirally from the first arrangement portion, and a linear portion that is connected to the end of the spiral portion and extends along the axis.

  According to this configuration, a part of the discharged coolant flows into the spiral portion of the first discharge groove. The spiral portion extends spirally from the first arrangement portion. For this reason, it becomes possible to allow the coolant to smoothly flow into the first discharge groove as the body rotates. The coolant that has passed through the spiral portion of the first discharge groove is then guided by the straight portion of the first discharge groove. As a result, it is possible to suppress involuntary turning of the chips while suppressing a decrease in the flow rate of the coolant flowing into the first discharge groove.

  The other end of the second discharge groove may be connected to the spiral portion of the first discharge groove.

  According to this structure, compared with the form in which the other end of the second discharge groove is connected to the linear portion of the first discharge groove, the direction of the coolant flowing from the second discharge groove to the first discharge groove and the merging It is possible to reduce the angle formed by the traveling direction of the coolant as the counterpart (that is, the coolant flowing through the spiral portion of the first discharge groove). As a result, the coolant that has passed through the second discharge groove can smoothly join the coolant that flows through the first discharge groove.

  By the way, if the angle formed by the extending direction of the second discharge groove and the axis is increased, it may be difficult to guide chips by the second discharge groove. As a result, chips may be clogged with the second discharge groove.

  Then, the length of the part which contributes to cutting among the cutting edges arrange | positioned at a 2nd arrangement | positioning part may be smaller than the length of the part which contributes to cutting among the cutting edges arrange | positioned at a 1st arrangement | positioning part.

  According to this configuration, the amount of chips generated by the cutting blades arranged in the second arrangement part in a predetermined period is larger than the amount of chips generated by the cutting blades arranged in the first arrangement part. Less. As a result, clogging of chips in the second discharge groove can be suppressed.

  The width of the first discharge groove may be larger than the width of the second discharge groove.

  As described above, in the first discharge groove, the cutting edge disposed in each of the first disposition portion and the second disposition portion in the portion on the base end side of the body with respect to the portion to which the second discharge groove is connected. The chips generated by are guided. By increasing the width of the first discharge groove that guides a large amount of chips in this way, it becomes possible to suppress clogging of chips in the first discharge groove.

It is a perspective view which shows the gun drill which concerns on 1st Embodiment. It is a perspective view which shows the gun drill of FIG. It is a side view which shows the gun drill of FIG. It is an enlarged view which shows the gun drill of FIG. It is an enlarged view which shows the gun drill of FIG. It is an enlarged view which shows the gun drill of FIG. It is an enlarged view which shows the gun drill of FIG. It is a side view which shows the gun drill of FIG. It is sectional drawing which shows the IX-IX cross section of FIG. It is sectional drawing which shows the XX cross section of FIG. It is a perspective view which shows the gun drill which concerns on 2nd Embodiment. It is an enlarged view which shows the gun drill of FIG. It is an enlarged view which shows the gun drill of FIG. It is an enlarged view which shows the gun drill of FIG. It is an enlarged view which shows the gun drill of FIG.

  Hereinafter, embodiments will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

[First Embodiment]
An outline of the gun drill 100 according to the first embodiment will be described with reference to FIGS. 1 to 3. The gun drill 100 is an example of a drilling tool used for deep hole machining. 1 and 2 are perspective views showing the gun drill 100. FIG. FIG. 3 is a side view showing the gun drill 100.

  The gun drill 100 includes a body 1. The body 1 is a rod-shaped member made of a metal material. The body 1 extends along the axis C from the proximal end portion 1a to the distal end portion 1b. The axis C is a virtual straight line extending substantially in the horizontal direction and penetrates the center of the body 1. An outer peripheral surface 1c, which is a cylindrical surface, extends between the base end portion 1a and the tip end portion 1b. A first discharge groove 11 and a second discharge groove 12 are formed on the outer peripheral surface 1c.

  For easy understanding, each drawing shows coordinates in which the direction in which the axis C extends is the X direction, and the direction orthogonal to the X direction is the Y direction and the Z direction. In FIG. 4 and subsequent figures, similar coordinates are shown.

  The base end 1a of the body 1 is inserted through a bush 6 that is a jig. A first cutting insert 31, a second cutting insert 32, and a third cutting insert 33 are attached to the distal end portion 1 b of the body 1. As will be described later, the first cutting insert 31, the second cutting insert 32, and the third cutting insert 33 are formed with cutting edges.

  The gun drill 100 rotates in the direction indicated by the arrow R in FIGS. 1 and 2 around the axis C as the motor (not shown) is driven. When the tip 1b of the body 1 is pressed against the work material, the cutting edges of the first cutting insert 31, the second cutting insert 32, and the third cutting insert 33 cut the work material. Thereby, a cylindrical hole is formed in the work material.

  During cutting with the gun drill 100, coolant is discharged from the tip 1 b of the body 1 toward the inside of the hole. The coolant cools the cutting edge and the work material heated by the frictional heat, and pushes away the chips generated by the cutting edge. The coolant including chips is guided to the base end 1a side by the first discharge groove 11 and the second discharge groove 12, and is discharged from the hole. The gun drill 100 can form a hole whose depth exceeds 10 times the diameter of the body 1 by cutting the work material while discharging chips.

  Next, the configuration of the gun drill 100 will be described in detail with reference to FIGS. 4 to 10. 4 to 7 are enlarged views showing the gun drill 100, and show the vicinity of the distal end portion 1 b of the body 1. FIG. 4 shows the gun drill 100 disassembled. FIG. 8 is a side view showing the gun drill 100, and shows the gun drill 100 so as to face the distal end portion 1b. 9 is a cross-sectional view showing a IX-IX cross section of FIG. FIG. 10 is a cross-sectional view showing the XX cross section of FIG.

  As shown in FIG. 4, a first tip seat 21, a second tip seat 22, and a third tip seat 23 are provided at the distal end portion 1 b of the body 1. The 1st tip seat 21 and the 2nd tip seat 22 are illustrations of the 1st arrangement part. The 3rd chip seat 23 is an illustration of the 2nd arrangement part. The first chip seat 21, the second chip seat 22, and the third chip seat 23 are provided at intervals in the circumferential direction of the axis C.

  The first chip seat 21, the second chip seat 22, and the third chip seat 23 are recessed portions that are independent of each other. The first tip seat 21 is open on the tip 1b side and the outer peripheral surface 1c side, and the second tip seat 22 and the third tip seat 23 are open only on the tip 1b side. The second tip seat 22 is provided at a position that intersects the axis C. The first chip seat 21, the second chip seat 22, and the third chip seat 23 are formed along the outer shapes of the first cutting insert 31, the second cutting insert 32, and the third cutting insert 33, respectively.

  The first chip seat 21, the second chip seat 22, and the third chip seat 23 have bottom surfaces 211, 221, 231, and side wall surfaces 212, 222, 232. The bottom surfaces 211, 221, and 231 are formed to face the direction indicated by the arrow R. Screw holes 213 and 223 are formed in the bottom surfaces 211 and 221. Similarly, a screw hole (not shown) is also formed in the bottom surface 231 of the third chip seat 23.

  As shown in FIGS. 4 and 5, the first cutting insert 31 has an upper surface 311 that exhibits a substantially parallelogram when viewed from the front. As shown in FIG. 4, the first cutting insert 31 has a peripheral side surface 313 that connects the upper surface 311 and an end surface (hereinafter referred to as “first lower surface”) facing the upper surface 311. . Two cutting edges 314 are formed at the intersection between the upper surface 311 and the peripheral side surface 313.

  The first cutting insert 31 is formed with a through hole 316 that penetrates from the upper surface 311 to the first lower surface. The first cutting insert 31 is disposed on the first chip seat 21 by having the first lower surface abut on the bottom surface 211 and the peripheral side surface 313 abut on the side wall surface 212. The first cutting insert 31 is detachably attached to the first chip seat 21 by a screw 71 that is inserted through the through hole 316 and screwed into the screw hole 213.

  As shown in FIG. 5, when the first cutting insert 31 is attached to the first chip seat 21, one cutting edge 314 is exposed from the distal end portion 1 b of the body 1. As a result, the portion of the cutting edge 314 having the length L1 (hereinafter also referred to as “the cutting width L1 of the cutting edge 314”) is arranged so as to contribute to the cutting. The cutting blades 314 arranged in this manner are inclined so as to approach the base end portion 1a (see FIGS. 1 and 2) from the axis C side toward the outer peripheral surface 1c side.

  As shown in FIGS. 4 and 5, the second cutting insert 32 has an upper surface 321 that has a substantially parallelogram shape when viewed from the front. As shown in FIG. 4, the second cutting insert 32 has a peripheral side surface 323 that connects the upper surface 321 and an end surface facing the upper surface 321 (hereinafter referred to as “second lower surface”). . Two cutting edges 324 are formed at the intersection between the upper surface 321 and the peripheral side surface 323.

  The second cutting insert 32 is formed with a through hole 326 that penetrates from the upper surface 321 to the second lower surface. The second cutting insert 32 is disposed on the second tip seat 22 by the second lower surface abutting the bottom surface 221 and the peripheral side surface 323 abutting the side wall surface 222. The second cutting insert 32 is detachably attached to the second chip seat 22 by a screw 72 that is inserted through the through hole 326 and screwed into the screw hole 223.

  As shown in FIG. 5, when the second cutting insert 32 is attached to the second chip seat 22, one cutting edge 324 is exposed from the distal end portion 1 b of the body 1. Accordingly, a portion of the cutting edge 324 having a length L2 (hereinafter also referred to as “cutting width L2 of the cutting edge 324”) is arranged so as to contribute to cutting. The cutting blade 324 arranged in this manner is inclined so as to protrude from the tip end portion 1b as it goes from the axis C side to the outer peripheral surface 1c side.

  As shown in FIG. 7, the third cutting insert 33 has an upper surface 331 that exhibits a substantially parallelogram when viewed from the front. As shown in FIG. 4, the third cutting insert 33 has a peripheral side surface 333 that connects an upper surface 331 and a lower surface 332 facing the upper surface 331. Two cutting edges 334 are formed at the intersection between the upper surface 331 and the peripheral side surface 333.

  The third cutting insert 33 is formed with a through hole 336 that penetrates from the upper surface 331 to the lower surface 332. The third cutting insert 33 is disposed on the third chip seat 23 by having the lower surface 332 abuts on the bottom surface 231 and the peripheral side surface 333 abuts on the side wall surface 232. The third cutting insert 33 is detachably attached to the third chip seat 23 by a screw 73 inserted through the through hole 336 and screwed into the screw hole.

  As shown in FIG. 7, when the third cutting insert 33 is attached to the third chip seat 23, the cutting edge 334 is exposed from the distal end portion 1 b of the body 1. Thereby, the part of length L3 (henceforth "the cutting width L3 of the cutting edge 334") among the cutting edges 334 is arrange | positioned so that it may contribute to cutting. The cutting edge 334 arranged in this manner is inclined so as to approach the proximal end portion 1a as it goes from the axis C side to the outer peripheral surface 1c side. The cutting width L3 of the cutting edge 334 of the third cutting insert 33 is the sum of the cutting width L1 of the cutting edge 314 of the first cutting insert 31 and the cutting width L2 of the cutting edge 324 of the second cutting insert 32 (that is, L1 + L2). Smaller than). For this reason, the sum of the cutting resistance that the cutting edges 314 and 324 receive from the work material during cutting is larger than the cutting resistance that the cutting edge 334 receives from the work material. Due to such a difference in cutting resistance, the body 1 receives a force in a direction away from the axis C.

  As described above, the first discharge groove 11 and the second discharge groove 12 are formed on the outer peripheral surface 1 c of the body 1. The first discharge groove 11 and the second discharge groove 12 are recessed from the outer peripheral surface 1 c of the body 1 toward the axis C. As shown in FIGS. 4 and 5, one end 11 a of the first discharge groove 11 is formed in a portion corresponding to the first tip seat 21 and the second tip seat 22 on the outer peripheral surface 1 c of the body 1. . As shown in FIG. 7, one end 12 a of the second discharge groove 12 is formed in a portion corresponding to the third chip seat 23 on the outer peripheral surface 1 c of the body 1.

  As shown in FIG. 8, the first discharge groove 11 is defined by a first wall surface 111 and a second wall surface 112. 4 and 5, the first discharge groove 11 extends along the axis C from the distal end portion 1b side of the body 1 toward the proximal end portion 1a side. That is, the angle formed by the extending direction of the first discharge groove 11 and the axis C is approximately 0 °. As shown in FIG. 4, the first chip seat 21 and the second chip seat 22 are recessed from the second wall surface 112 in a direction substantially perpendicular to the second wall surface 112.

  As shown in FIG. 8, the width W1 of the first discharge groove 11 (that is, the maximum value of the distance between the first wall surface 111 and the second wall surface 112) is such that the first wall surface 111 and the second wall surface 112 are different. It is determined by the angle θ1 formed. The angle θ1 is preferably 100 ° or more and less than 180 °.

  The second discharge groove 12 is defined by the first wall surface 121 and the second wall surface 122. The width W2 of the second discharge groove 12 (that is, the maximum value of the distance between the first wall surface 121 and the second wall surface 122) is determined by the angle θ21 formed by the first wall surface 121 and the second wall surface 122. The angle θ21 is smaller than the angle θ1 of the first discharge groove 11. The width W2 of the second discharge groove 12 is smaller than the width W1 of the first discharge groove 11.

  As shown in FIGS. 6 and 7, the second discharge groove 12 includes a straight portion 12 </ b> L and a spiral portion 12 </ b> S. The straight line portion 12L extends along the axis C from the distal end portion 1b side of the body 1 toward the proximal end portion 1a side. That is, the straight portion 12L extends linearly.

  The spiral portion 12S is connected to the end portion of the straight portion 12L, and extends in a spiral shape about the axis C. That is, the angle θ22 formed by the extending direction of the spiral portion 12S and the axis C shown in FIG. 6 is larger than 0 °. The angle θ22 can be set to various values larger than 0 °.

  While the first discharge groove 11 extends linearly along the axis C, the spiral portion 12S of the second discharge groove 12 extends spirally. Accordingly, the spiral portion 12S gradually approaches the first discharge groove 11 toward the base end portion 1a side of the body 1. The other end 12 b of the second discharge groove 12 is connected in the middle of the first discharge groove 11. Specifically, as shown in FIGS. 4 and 5, the other end 12 b of the second discharge groove 12 is connected to the first discharge groove 11 from the first wall surface 111 side. Therefore, while the first discharge groove 11 and the second discharge groove 12 appear in the cross section of the body 1 in the vicinity of the front end portion 1b (see FIG. 9), the base end portion 1a is more than the other end 12b of the second discharge groove 12. Only the first discharge groove 11 appears in the cross section of the body 1 on the side (see FIG. 10).

  As shown in FIG. 4, a first guide pad seat 41 and a second guide pad seat 42 are provided on the outer peripheral surface 1 c in the vicinity of the distal end portion 1 b of the body 1. Specifically, a relatively wide space is formed on the outer peripheral surface 1c between the first discharge groove 11 and the straight portion 12L of the second discharge groove 12, and the first guide pad seat 41 is formed in the space. And a second guide pad seat 42 is provided.

  The first guide pad seat 41 and the second guide pad seat 42 are recessed from the outer peripheral surface 1 c of the body 1 toward the axis C. Screw holes (not shown) are formed in the bottom surfaces of the first guide pad seat 41 and the second guide pad seat 42.

  The first guide pad 51 is disposed on the first guide pad seat 41, and the second guide pad 52 is disposed on the second guide pad seat 42. The first guide pad 51 is detachably attached to the first guide pad 51 by a screw 74 inserted through the through hole 511 and screwed into the screw hole. The second guide pad 52 is detachably attached to the second guide pad 52 by a screw 75 inserted through the through hole 521 and screwed into the screw hole.

  As shown in FIG. 10, a flow path 14 is formed inside the body 1. The flow path 14 allows the coolant to flow from the base end 1a side of the body 1 to the tip end 1b side. The flow path 14 is branched into a first flow path 141 and a second flow path 142 shown in FIG.

  As shown in FIG. 4, a first opening 151, a second opening 152, a first guide groove 161, and a second guide groove 162 are formed at the distal end portion 1 b of the body 1. The first opening 151 communicates with the first flow path 141, and the second opening 152 communicates with the second flow path 142. The first guide groove 161 and the second guide groove 162 are recessed toward the base end 1 a side of the body 1. The first guide groove 161 extends so as to allow the first opening 151 and the second discharge groove 12 to communicate with each other. The second guide groove 162 extends so as to allow the second opening 152 and the first discharge groove 11 to communicate with each other.

  Next, deep hole machining with the gun drill 100 will be described in detail. As described above, the gun drill 100 rotates about the axis C in the direction indicated by the arrow R in FIGS. When the front end portion 1b of the body 1 is pressed against the work material, the cutting edges 314, 324, and 334 of the first cutting insert 31, the second cutting insert 32, and the third cutting insert 33 cut the work material to form holes. Form. At this time, the upper surfaces 311, 321 and 331 function as rake surfaces, and the peripheral side surfaces 313, 323 and 333 function as flank surfaces.

  The depth dimension of the hole can be extended by pressing the body 1 against the work material and causing the tip 1b to enter the hole of the work material. As described above, the body 1 receives a force in a direction away from the axis C due to a difference in cutting resistance. For this reason, when the body 1 enters the hole, the first guide pad 51 and the second guide pad 52 are pressed against the inner surface of the hole. Thereby, the deformation | transformation of the body 1 is suppressed and the dimensional accuracy of a hole improves. Further, as the body 1 rotates, the first guide pad 51 and the second guide pad 52 slide relative to the inner surface of the hole. Thereby, the processing trace of the inner surface of a hole becomes small, and the said inner surface becomes smooth.

  At the time of cutting with the cutting edges 314, 324, 334, coolant is caused to flow through the flow path 14 inside the body 1. The coolant is divided into the first flow path 141 and the second flow path 142, and is discharged from the first opening 151 and the second opening 152 toward the inside of the hole. The coolant cools the cutting edges 314, 324, and 334, which have been heated by frictional heat during cutting, and the work material.

  A part of the coolant discharged from the first opening 151 flows into the one end 12a (see FIG. 6) of the second discharge groove 12 through the first guide groove 161, as indicated by an arrow F1 in FIG. Further, a part of the coolant discharged from the second opening 152 flows into the one end 11a of the first discharge groove 11 through the second guide groove 162 as indicated by an arrow F2.

  The coolant that has flowed into the one end 11a of the first discharge groove 11 is guided by the first discharge groove 11 and flows toward the base end 1a side of the body 1 as indicated by an arrow F3 in FIG. The coolant pushes away the chips generated by the cutting edge 314 of the first cutting insert 31 and the cutting edge 324 of the second cutting insert 32.

  The coolant that has flowed into the one end 12a of the second discharge groove 12 is first guided by the straight portion 12L and flows toward the base end portion 1a of the body 1 as indicated by an arrow F5 in FIG. The coolant pushes away the chips generated by the cutting edge 334 of the third cutting insert 33.

  The coolant that has passed through the straight portion 12L then flows into the spiral portion 12S. As shown by an arrow F6 in FIG. 6, the coolant is guided by the spiral portion 12S and flows toward the base end portion 1a side of the body 1 while turning. Then, as indicated by an arrow F <b> 4 in FIG. 5, the second discharge groove 12 flows into the first discharge groove 11 from the other end 12 b. The coolant merges with the flowing coolant as indicated by the arrow F3, and further flows toward the base end 1a side of the body 1.

  Next, the effect | action by the body 1 and its effect are demonstrated.

  According to the configuration of the body 1, chips generated by the cutting edge 334 of the third cutting insert 33 are guided by the second discharge groove 12 and enter the first discharge groove 11. The chips are guided by the first discharge groove 11 together with the chips generated by the cutting edges 314 and 324 of the first cutting insert 31 and the second cutting insert 32, and are discharged from the holes.

  In other words, according to the configuration of the body 1, the second discharge groove 12 is not formed on the base end portion 1 a side from the portion of the body 1 where the first discharge groove 11 and the second discharge groove 12 are connected. Chips generated by the cutting edges 314, 324, and 334 disposed in the first chip seat 21, the second chip seat 22, and the third chip seat 23 can be discharged out of the hole. Thereby, it becomes possible to suppress a decrease in rigidity of the body 1.

  Further, the other end 12 b of the second discharge groove 12 is connected to the middle of the first discharge groove 11 on the outer peripheral surface 1 c of the body 1. As a result, it is possible to suppress clogging of chips in the second discharge groove 12 as compared with a configuration in which the second discharge groove 12 penetrates the inside of the body 1 and is connected to the middle of the first discharge groove 11. Become. Further, the coolant flow path 14 and the like can be easily formed inside the body 1.

  Further, the first discharge groove 11 extends along the axis C, and the second discharge groove 12 extends in a spiral shape.

  According to this configuration, even when the body 1 is arranged so that the axis C is along the horizontal direction, chips are guided in the horizontal direction by the first discharge groove 11. As a result, involuntary turning of the chips can be suppressed, and the chips can be smoothly guided and discharged out of the hole.

  When the body 1 is viewed from a direction orthogonal to the axis C, the angle between the extending direction of the first discharge groove 11 and the axis C (that is, 0 °) is such that the extending direction of the second discharge groove 12 and the axis are the same. It is smaller than the angle θ22 formed.

  According to this configuration, the second discharge groove 12 is extended so as to gradually approach the first discharge groove 11 toward the base end 1a side of the body 1, and the second discharge groove 12 is connected to the first discharge groove. It becomes possible to make it.

  The second discharge groove 12 includes a straight portion 12L extending from the third tip seat 23 along the axis C, and a spiral portion 12S connected to the end of the straight portion 12L and extending spirally.

  According to this configuration, it is possible to secure a relatively wide space in a portion between the first discharge groove 11 and the straight portion 12 </ b> L of the second discharge groove 12 in the outer peripheral surface 1 c of the body 1. . Thereby, the space can be used for attaching the first guide pad 51 and the second guide pad 52.

  The cutting width L3 of the cutting edge 334 arranged in the third chip seat 23 is smaller than the cutting width L1 + L2 of the cutting edges 314, 324 arranged in the first chip seat 21 and the second chip seat 22.

  According to this configuration, the amount of chips generated by the cutting edge 334 disposed on the third chip seat 23 during the predetermined period is the cutting edge 314 disposed on the first chip seat 21 and the second chip seat 22. , 324 and less than the amount of chips produced. As a result, clogging of chips in the second discharge groove 12 can be suppressed.

  The width W1 of the first discharge groove 11 is larger than the width W2 of the second discharge groove 12.

  As described above, in the portion of the first discharge groove 11 closer to the base end portion 1a of the body 1 than the portion to which the second discharge groove 12 is connected, the first chip seat 21, the second chip seat 22, Chips generated by the cutting edges 314, 324, and 334 arranged in the three-chip seats 23 are guided. By increasing the width W1 of the first discharge groove 11 that guides a large amount of chips in this way, it becomes possible to suppress clogging of the chips in the first discharge groove 11.

[Second Embodiment]
A gun drill 100A according to the second embodiment will be described with reference to FIGS. FIG. 11 is a perspective view showing the gun drill 100A. 12 to 15 are enlarged views showing the gun drill 100A, and show the vicinity of the tip 1b of the body 1A.

  The gun drill 100A is an example of a drilling tool used for deep hole machining, similar to the gun drill 100 according to the first embodiment. The shapes of the first discharge groove 17 and the second discharge groove 18 of the gun drill 100 </ b> A are different from the shapes of the first discharge groove 11 and the second discharge groove 12 of the gun drill 100. Of the configuration of the gun drill 100A, those having the same functions as the configuration of the gun drill 100 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The gun drill 100A includes a body 1A. The body 1A is a rod-shaped member made of a metal material. The body 1A extends along the axis C from the proximal end portion 1a to the distal end portion 1b. The axis C is an imaginary straight line extending substantially in the horizontal direction and penetrates the center of the body 1A. An outer peripheral surface 1c, which is a cylindrical surface, extends between the base end portion 1a and the tip end portion 1b.

  A first discharge groove 17 and a second discharge groove 18 are formed on the outer peripheral surface 1c of the body 1A. The first discharge groove 17 and the second discharge groove 18 are recessed from the outer peripheral surface 1c of the body 1A toward the axis C. As shown in FIG. 12, one end 17a of the first discharge groove 17 is formed in a portion corresponding to the first chip seat 21 and the second chip seat 22 on the outer peripheral surface 1c of the body 1A. As shown in FIG. 14, one end 18a of the second discharge groove 18 is formed at a portion corresponding to the third chip seat 23 on the outer peripheral surface 1c of the body 1A.

  As shown in FIG. 11, the first discharge groove 17 is defined by a first wall surface 171 and a second wall surface 172. As shown in FIG. 15, the first discharge groove 17 has a spiral portion 17S and a linear portion 17L. The spiral portion 17S extends spirally around the axis C from the tip portion 1b of the body 1A. That is, the angle θ7 formed by the extending direction of the spiral portion 17S and the axis C is greater than 0 °. The angle θ7 can be set to various values larger than 0 °. The straight line portion 17L is connected to the end of the spiral portion 17S and extends along the axis C. That is, the straight line portion 17L extends linearly.

  As shown in FIG. 13, the second discharge groove 18 has a straight portion 18 </ b> L and a spiral portion 18 </ b> S. The straight line portion 18L extends along the axis C from the distal end portion 1b side of the body 1A toward the proximal end portion 1a side. That is, the straight portion 18L extends linearly. The spiral portion 18S is connected to the end portion of the straight portion 18L and extends in a spiral shape with the axis C as the center. That is, the angle θ8 formed by the extending direction of the spiral portion 18S and the axis C shown in FIG. 13 is larger than 0 °.

  The angle θ8 is larger than the aforementioned angle θ7 (see FIG. 15). Thereby, the spiral portion 18S of the second discharge groove 18 gradually approaches the spiral portion 17S of the first discharge groove 17 toward the base end portion 1a side of the body 1A. The other end 18 b of the second discharge groove 18 is connected to the spiral portion 17 </ b> S of the first discharge groove 17. Specifically, as shown in FIG. 15, the other end 18 b of the second discharge groove 18 is connected to the first discharge groove 17 from the first wall surface 171 side.

  Next, the deep hole machining by the gun drill 100A will be described in detail. The gun drill 100A rotates about the axis C in the direction indicated by the arrow R in FIG. When the front end portion 1b of the body 1A is pressed against the work material, the cutting edges 314, 324, and 334 of the first cutting insert 31, the second cutting insert 32, and the third cutting insert 33 cut the work material to form holes. Form.

  During cutting by the cutting edges 314, 324, and 334, coolant is discharged from the first opening 151 and the second opening 152 shown in FIG. 11 toward the inside of the hole of the work material. The coolant cools the cutting edges 314, 324, and 334, which have been heated by frictional heat during cutting, and the work material.

  Here, the direction in which the spiral portion 17S of the first discharge groove 17 turns in the direction from the distal end portion 1b to the base end portion 1a of the body 1A is the direction in which the gun drill 100A rotates (that is, indicated by the arrow R in FIG. The opposite direction). For this reason, the one end 17a of the first discharge groove 17 is caused to flow in so as to receive the coolant as the body 1A rotates, as indicated by an arrow F11 in FIG.

  As indicated by an arrow F12, the coolant that has flowed into the one end 17a of the first discharge groove 17 is first guided by the spiral portion 17S and flows toward the base end portion 1a of the body 1A. The coolant pushes away the chips generated by the cutting edge 314 of the first cutting insert 31 and the cutting edge 324 of the second cutting insert 32.

  In addition, the coolant discharged toward the inside of the hole of the work material also flows into the one end 18 a of the second discharge groove 18. As shown by an arrow F9 in FIG. 13, the coolant is first guided by the straight portion 18L and flows toward the base end portion 1a of the body 1A. The coolant pushes away the chips generated by the cutting edge 334 of the third cutting insert 33.

  The coolant that has passed through the straight portion 18L then flows into the spiral portion 18S. As shown by the arrow F10 in FIG. 13, the coolant is guided by the spiral portion 18S and flows toward the base end portion 1a of the body 1A while turning. Then, as indicated by an arrow F <b> 13 in FIG. 15, the gas flows into the spiral portion 17 </ b> S of the first discharge groove 17 from the other end 18 b of the second discharge groove 18. The coolant merges with the flowing coolant as indicated by an arrow F12, and further flows toward the base end 1a side of the body 1A as indicated by an arrow F14.

  Next, the effect | action by the body 1A and its effect are demonstrated.

  According to this configuration, a part of the discharged coolant flows into the spiral portion 17 </ b> S of the first discharge groove 17. The spiral portion 17S extends spirally from the first tip seat 21 and the second tip seat 22. For this reason, the coolant can smoothly flow into the first discharge groove 17 as the body 1A rotates. The coolant that has passed through the spiral portion 17 </ b> S of the first discharge groove 17 is then guided by the linear portion 17 </ b> L of the first discharge groove 17. As a result, it is possible to suppress involuntary turning of the chips while suppressing a decrease in the flow rate of the coolant flowing into the first discharge groove 17.

  The other end 18 b of the second discharge groove 18 is connected to the spiral portion 17 </ b> S of the first discharge groove 17.

  According to this configuration, the coolant that flows into the first discharge groove 17 from the second discharge groove 18 as compared with the form in which the other end 18 b of the second discharge groove 18 is connected to the linear portion 17 </ b> L of the first discharge groove 17. It is possible to reduce the angle formed by the traveling direction of the coolant and the traveling direction of the coolant that is the joining partner (that is, the coolant flowing through the spiral portion 17S of the first discharge groove 17). As a result, it is possible to smoothly merge the coolant that has passed through the second discharge groove 18 with the coolant that flows through the first discharge groove 17.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate.

  The aforementioned body 1, 1 </ b> A is provided with the first tip seat 21 and the second tip seat 22 as the first placement portion, and the third tip seat 23 as the second placement portion. And the 1st cutting insert 31, the 2nd cutting insert 32, and the 3rd cutting insert 33 attached to them detachably have the cutting blades 314,324,334, respectively. However, the body according to the present invention is not limited to such a form. For example, the cutting edge according to the present invention may be formed integrally with the body.

DESCRIPTION OF SYMBOLS 1, 1A: Body 1a: Base end part 1b: Front-end | tip part 1c: Outer peripheral surface 11, 17: 1st discharge groove 11a, 17a: One end 12, 18: 2nd discharge groove 12L, 17L, 18L: Linear part 12S, 17S , 18S: spiral part 12a: one end 12b: other end 21: first tip seat (first arrangement part)
22: 2nd chip seat (1st arrangement part)
23: 3rd chip seat (2nd arrangement part)
100, 100A: Gun drill (drilling tool)
314, 324, 334: Cutting edge

Claims (7)

A drilling tool body,
A first placement portion and a second placement at which the cutting edges for cutting the work material are disposed at the front end portion of the body extending along a predetermined axis and spaced from each other in the circumferential direction of the shaft. And
One end of the outer peripheral surface of the body is formed at a portion corresponding to the first placement portion, extends from the distal end portion side to the proximal end portion side of the body, and is disposed at the first placement portion. A first discharge groove for guiding chips generated by the blade;
One end of the outer peripheral surface of the body is formed at a portion corresponding to the second placement portion, extends from the distal end portion side to the proximal end portion side of the body, and is disposed at the second placement portion. A second discharge groove for guiding chips generated by the blade,
The second discharge groove extends spirally, and the other end is connected to the middle of the first discharge groove on the outer peripheral surface of the body,
The first discharge groove is a body extending along the axis. When viewing the body from a direction perpendicular to the axis,
The body according to claim 1, wherein an angle formed between the extending direction of the first discharge groove and the axis is smaller than an angle formed between the extending direction of the second discharge groove and the axis. The second discharge groove is
A linear portion extending along the axis from the second placement portion;
The body according to claim 2, further comprising: a spiral portion connected to an end portion of the straight portion and extending in a spiral shape. The first discharge groove is
A spiral portion extending spirally from the first placement portion;
The body according to claim 1, further comprising: a straight portion connected to an end portion of the spiral portion and extending along the axis.   The body according to claim 4, wherein the other end of the second discharge groove is connected to a spiral portion of the first discharge groove.   The length of the part which contributes to cutting among the cutting edges arrange | positioned at the said 2nd arrangement | positioning part is smaller than the length of the part which contributes to cutting among the cutting edges arrange | positioned at the said 1st arrangement | positioning part. The body according to any one of 5 to 5.   The body according to any one of claims 1 to 6, wherein a width of the first discharge groove is larger than a width of the second discharge groove.