JP2008178941A - Drill unit, and drill and holder used in the drill unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill unit capable of assuring rigidity of a tool for improving a service life of the tool, and a drill and a holder used in the drill unit. <P>SOLUTION: Since the drill unit 1 has a drill 10 designed to have a suction path 16 recessed on an outer peripheral surface of a body 11 to discharge cut chips through the suction path 16, the rigidity of the tool can be assured and the service life of the tool can be improved compared with a case in which the body 11 is structured to be hollow and the cut chips are discharged through the body 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drill unit and a drill and a holder used in the drill unit, and more particularly, a drill unit that can ensure tool rigidity and improve tool life, and a drill and a holder used in the drill unit. It is about.

  Generally, in drilling with a drill, it is important to use a cutting fluid to remove chips in order to extend the tool life and ensure machining accuracy. However, the cutting fluid contains harmful substances such as chlorine and phosphorus, which may cause environmental pollution. For this reason, in recent years, development of a technique capable of suppressing the use of cutting fluid has been desired.

Therefore, for example, Patent Document 1 discloses a drill that sucks chips and discharges the sucked chips through a hollow tool body.
Japanese Patent Laid-Open No. 40-19634

  However, the drill in Patent Document 1 has a problem that the tool main body is hollow, so that the tool rigidity is lowered and the tool life is shortened.

  The present invention has been made to solve the above-described problems, and provides a drill unit that can ensure tool rigidity and improve tool life, and a drill and a holder used in the drill unit. The purpose is to do.

  In order to solve this object, a drill unit according to a first aspect of the present invention is provided with a main body portion rotated about an axis, a blade portion having a cutting edge and disposed at a tip of the main body portion, and the blade portion. And a drill having a groove that forms a rake face of the cutting edge, and a holder having an insertion hole into which the main body portion of the drill is inserted, and shrink-fitting the main body portion of the drill into the insertion hole of the holder The drill is held by the holder, and the drill is recessed in the outer peripheral surface of the main body, and is continuously provided in the groove and extended to the rear end surface of the main body. The main body has an outer diameter smaller than the outer diameter of the blade portion, and the holder has an air passage recessed in the outer peripheral surface, and the outer diameter is the blade portion of the drill. The outer diameter of the When the air is sucked into the insertion hole, the chips generated by the cutting edge of the drill and sucked into the groove are sucked through the suction path and discharged from the rear end of the main body. Yes.

  The drill unit according to a second aspect is the drill unit according to the first aspect, wherein the suction path of the drill is formed by being twisted in the same direction as the rotation direction of the main body.

  The drill unit according to claim 3 is the drill unit according to claim 1 or 2, wherein the air flow path of the holder extends from the front end surface of the holder to the rear end side, thereby leading the front end of the holder. The drill is held on the front end surface side of the holder where the air passage is opened.

  The drill unit according to a fourth aspect is the drill unit according to any one of the first to third aspects, wherein the air passage of the holder is formed by twisting in a direction opposite to the rotation direction of the drill.

  The drill unit according to a fifth aspect is the drill unit according to the fourth aspect, wherein the air passages of the holder are formed in multiple lines.

  The drill unit according to claim 6 is the drill unit according to any one of claims 1 to 5, wherein the length of the blade portion in the axial direction is 50% of the diameter of the blade portion. The length is set to 150% or less.

  The drill according to claim 7 is used in the drill unit according to any one of claims 1 to 6.

  The holder according to claim 8 is used in the drill unit according to any one of claims 1 to 6.

  According to the drill unit of the first aspect, since the suction path of the drill is recessed in the outer peripheral surface of the main body, the suction path is between the holder and the drill when the drill is held by the holder. A gap corresponding to the cross-sectional area can be provided. In addition, since the suction path is connected to the groove and extends to the rear end surface of the main body, the suction generated in the insertion hole of the holder generates the chips generated by the cutting blade and accommodated in the groove. Can be forcibly sucked through the suction path, and the sucked chips can be discharged from the rear end of the main body through the holder.

  Therefore, compared with the conventional product, it is possible to suppress (or make unnecessary) the use of the cutting fluid for removing chips, and to prevent environmental pollution. Moreover, since the suction path is recessed in the outer peripheral surface of the main body part and the drill is configured to discharge chips through the suction path, the drill is configured so that the main body part is hollow as in the conventional product. Compared with the case where chips are discharged through the main body, tool rigidity can be ensured and the tool life can be improved.

  In addition, since the suction path is extended to the rear end surface of the main body portion and opened to the rear end surface of the main body portion, for example, in order to discharge chips compared to the case of opening to the side surface of the main body portion. There is an effect that the structure of the holder can be simplified.

  Also, the drill is configured so that the outer diameter of the main body is smaller than the outer diameter of the blade, and the holder into which the main body of the drill is inserted is configured so that the outer diameter is smaller than the outer diameter of the blade of the drill Therefore, even if the hole to be machined in the workpiece is deeper than the length of the blade in the axial direction of the drill, the workpiece and the holder can be normally cut without interference. it can.

  By the way, when the machining hole is deeper than the length of the blade portion in the axial direction of the drill, the holder enters the machining hole, so that it is formed between the workpiece and the holder for sucking air during intake. The gap is narrow and the intake resistance increases. On the other hand, according to the present invention, since the air passage is recessed in the outer peripheral surface of the holder, the gap formed between the workpiece and the holder is divided into the cross-sectional area of the air passage. Can only be enlarged.

  Therefore, even when the machining hole is deeper than the length of the blade portion in the axial direction of the drill, air can be sufficiently fed into the machining hole through the air passage as the drill rotates. There is an effect that the intake efficiency can be improved by lowering.

  Further, according to the drill unit of the present invention, the holder and the drill are configured separately, and the drill main body is fitted into the insertion hole of the holder and the drill is held by the holder. Can be configured. Therefore, only the drill that requires strength can be made of an expensive material, and the tool cost can be reduced as compared with the case where the entire drill unit is made of an expensive material. .

  According to the drill unit of the second aspect, in addition to the effect produced by the drill unit of the first aspect, the suction path of the drill is formed by being twisted in the same direction as the rotation direction of the main body portion. The chips can be smoothly discharged along the suction path by the rotating rotational force. Therefore, there is an effect that the chip dischargeability can be improved.

  According to the drill unit of the third aspect, in addition to the effect produced by the drill unit according to the first or second aspect, the air passage of the holder extends from the front end surface of the holder to the rear end side. Since the drill is held on the tip side of the holder where the air passage is opened, the drill is held so that the opening of the air passage of the holder and the groove of the drill are connected to each other. In this case, there is an effect that air can be directly fed into the groove through the air passage. As a result, there is an effect that the intake resistance can be further reduced and the intake efficiency can be further improved.

  According to the drill unit of the fourth aspect, in addition to the effect produced by the drill unit according to any one of the first to third aspects, the air passage of the holder is formed by twisting in the direction opposite to the rotation direction of the drill. Therefore, there is an effect that the air can be forcibly fed through the air passage by the rotational force by which the drill is rotated. As a result, there is an effect that the intake resistance can be further reduced and the intake efficiency can be further improved.

  According to the drill unit of the fifth aspect, in addition to the effect produced by the drill unit according to the fourth aspect, since the air passage of the holder is formed in multiple lines, compared to the case of one line, There is an effect that the amount of air sent into the processing hole can be increased. As a result, there is an effect that the intake resistance can be further reduced and the intake efficiency can be further improved.

  According to the drill unit of the sixth aspect, in addition to the effect produced by the drill unit according to any one of the first to fifth aspects, the drill has a length of the blade portion in the axial direction and an outer diameter of the blade portion. Since the length is set to 50% or more and 150% or less, there is an effect that both improvement in tool life and improvement in machining accuracy can be achieved.

  That is, when the length of the blade portion in the axial direction is shorter than 50% of the outer diameter of the blade portion, the rigidity of the blade portion is lowered and the tool life is reduced. Since the length of the blade portion in the axial direction is 50% or more of the outer diameter of the blade portion, it is possible to ensure the rigidity of the blade portion and to suppress the reduction of the tool life.

  On the other hand, if the length of the blade portion in the axial direction is longer than 150% of the outer diameter of the blade portion, the deflection of the drill is likely to occur during cutting, and the length of the blade portion in the axial direction. By making 150% or less of the outer diameter of the blade portion, it is possible to suppress drill runout. Thereby, both improvement of tool life and improvement of machining accuracy can be achieved.

  According to the drill of Claim 7, there exists an effect similar to the drill used for the drill unit in any one of Claim 1-6.

  According to the holder of Claim 8, there exists an effect similar to the holder used for the drill unit in any one of Claim 1-6.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. First, a schematic configuration of the drill unit 1 will be described with reference to FIG. Fig.1 (a) is a front view of the drill unit 1 in 1st Embodiment of this invention, FIG.1 (b) expands the drill unit 1 in the arrow Ib direction view of Fig.1 (a). It is an enlarged side view shown.

  The drill unit 1 is for performing cutting (for example, drilling) on a workpiece by a rotational force transmitted from a processing machine (not shown) (see FIG. 4), as shown in FIG. The drill 10 and the holder 20 that holds the drill 10 are provided. The drill unit 1 is provided with the rotational force of the processing machine by attaching the holder 20 to the processing machine via a collet (not shown).

  The drill 10 is a cutting tool for cutting the workpiece while being rotated by the transmitted rotational force of the processing machine by being held by the holder 20 and being rotated by the transmitted rotational force of the processing machine. As shown in FIG. 1, it is made of a cemented carbide obtained by pressure-sintering tungsten carbide (WC) or the like. However, the drill 10 is not limited to cemented carbide, and may be made of high-speed tool steel or the like.

  As described above, the holder 20 is attached to a processing machine via a collet (not shown) and holds the drill 10, and is made of high-speed tool steel as shown in FIG. Yes. However, the holder 20 is not limited to high-speed tool steel, and may be made of cemented carbide or the like.

  Next, the detailed configuration of the drill 10 will be described with reference to FIG. FIG. 2A is a front view of the drill 10, and FIG. 2B is an enlarged side view showing the drill 10 in an arrow IIb direction view of FIG. 2A.

  As shown in FIG. 2, the drill 10 includes a main body 11, a blade 12 disposed on the distal end side (the right side in FIG. 2A) of the main body 11, and a recessed portion on the outer peripheral surface of the main body 11. The suction path 16 is mainly provided. In the present embodiment, the outer diameter of the blade portion 12 (the diameter of the largest portion of the blade portion 12) Dk is set to 10 mm.

  The main body 11 is a part that is inserted into an insertion hole 21 of the holder 20 to be described later, and is formed in a columnar shape having an axis O as shown in FIG. The main body 11 has an outer diameter Db smaller than the outer diameter Dk of the blade part 12. Accordingly, a step 12 a is formed between the main body 11 and the blade 12 in the drill 10.

  Therefore, when the drill 10 is held by the holder 20, the tip end surface of the holder 20 can be abutted against the stepped portion 12a of the drill 10 and shrink-fitted (see FIG. 1). Can be improved.

  The blade part 12 is a part for performing cutting, and as shown in FIG. 2, the blade part 12 mainly includes a groove 13 and a cutting edge 14. The groove 13 is for accommodating chips generated by the cutting edge 14, and the two grooves 13a and 13b are in the same direction as the rotation direction of the main body 11 (counterclockwise in FIG. 2 (b)). It is formed by twisting. That is, in the present embodiment, the groove 13 is formed in a right twist.

  The cutting edge 14 is a cutting edge formed on the distal end side (right side in FIG. 2A) of the blade portion 12, and flank surfaces 15a and 15b and grooves 13a and 13b formed on the distal end of the blade portion 12 are respectively provided. Two cutting edges 14a and 14b are formed symmetrically with respect to the axis O at each intersecting ridge line portion.

  The suction path 16 is for discharging chips contained in the groove 13, and the two suction paths 16a and 16b are twisted in the same direction as the rotation direction of the main body 11 (that is, the present embodiment). Then, it is formed of a lead substantially the same as the lead of the groove 13 and the two suction paths 16a and 16b are connected to the two grooves 13a and 13b, respectively.

  It should be noted that, as described in claim 2, being formed by being twisted in the same direction as the rotation direction of the main body, as in the present embodiment, the rotation direction of the main body 11 is clockwise (FIG. 2B). In the case of (counterclockwise), this means that the suction path 16 is formed in a right-handed twist, while in the case where the rotation direction of the main body portion 11 is counterclockwise (FIG. 2 (b) clockwise), the suction path It means that 16 is formed in the left twist.

  As shown in FIG. 2A, the suction path 16 extends to the rear end surface of the main body 11 (the left side surface in FIG. 2A), and the suction path 16 is the rear end surface of the main body 11. In the state where the drill 10 is held by the holder 20, it is configured to communicate with an insertion hole 21 of the holder 20 described later (see FIG. 4).

  Further, the groove width of the suction path 16 is configured to be 50% of the outer diameter Db of the main body 11, and the groove depth of the suction path 16 is 17.5% of the outer diameter Db of the main body 11. Configured to depth. The groove width of the suction path 16 is preferably set to a width of 45% or more and 55% or less of the outer diameter Db of the main body 11.

  That is, when the groove width of the suction path 16 is smaller than 45% of the outer diameter Db of the main body 11, the cross-sectional area of the suction path 16 becomes small, and the suction path 16 is discharged when chips are discharged through the suction path 16. Where the chip is likely to be clogged, the groove width of the suction path 16 is set to 45% or more of the outer diameter Db of the main body portion 11 to secure the cross-sectional area of the suction path 16 and suppress chip clogging. Can do.

  On the other hand, when the groove width of the suction path 16 is wider than 55% of the outer diameter Db of the main body 111, the contact area between the holder 20 and the drill 10 decreases, and the holding force of the drill 10 by the holder 20 decreases. However, by making the groove width of the suction path 16 equal to or less than 55% of the outer diameter Db of the main body portion 11, a contact area between the holder 20 and the drill 10 can be secured and a decrease in holding force can be suppressed. . Thereby, it is possible to achieve both the improvement of the chip discharging property and the improvement of the holding force of the drill 10 by the holder 20.

  Furthermore, the groove depth of the suction path 16 is desirably set to a depth of 15% or more and 20% or less of the outer diameter Db of the main body 11. That is, when the groove depth of the suction path 16 is shallower than 15% of the outer diameter Db of the main body portion 11, the cross-sectional area of the suction path 16 becomes small, and the suction path when discharging chips through the suction path 16. When the chip 16 is easily clogged, the groove depth of the suction path 16 is set to 15% or more of the outer diameter Db of the main body portion 11 to secure the cross-sectional area of the suction path 16 and suppress chip clogging. can do.

  On the other hand, when the groove depth of the suction path 16 is deeper than 20% of the outer diameter Db of the main body 11, the tool rigidity is lowered and the tool life is reduced. By setting it as the magnitude | size of 20% or less of the outer diameter Db of the part 11, tool rigidity can be ensured and the fall of a tool life can be suppressed. Thereby, coexistence with the improvement of chip discharge | emission property and the improvement of a tool life can be aimed at.

  Further, the drill 10 is configured such that the length X of the blade portion 12 in the direction of the axis O is substantially equal to the outer diameter Dk of the blade portion 12. The length X of the blade portion 12 in the direction of the axis O is preferably set to a length that is 50% or more and 150% or less of the outer diameter Dk of the blade portion 12.

  That is, when the length X of the blade portion 12 in the direction of the axis O is shorter than 50% of the outer diameter Dk of the blade portion 12, the rigidity of the blade portion 12 is lowered, leading to a reduction in tool life. Since the length X of the blade portion 12 in the direction of the axis O is set to 50% or more of the outer diameter Dk of the blade portion 12, the rigidity of the blade portion 12 can be ensured, and the decrease in tool life is suppressed. Can do.

  On the other hand, when the length X of the blade portion 12 in the direction of the axis O is longer than 150% of the outer diameter Dk of the blade portion 12, the drill 10 is likely to be shaken during the cutting process. By setting the length X of the blade portion 12 to 150% or less of the outer diameter Dk of the blade portion 12, the deflection of the drill 10 can be suppressed. Thereby, both improvement of tool life and improvement of machining accuracy can be achieved.

  Next, a detailed configuration of the holder 20 will be described with reference to FIG. Fig.3 (a) is a front view of the holder 20, FIG.3 (b) is an enlarged side view which expands and shows the holder 20 in the arrow IIIb direction view of Fig.3 (a). In FIG. 3A, a part of the holder 20 is viewed in cross section.

  As shown in FIG. 3, the holder 20 is formed in a columnar shape, and an insertion hole 21 is formed through the inside. The holder 20 is configured such that the outer diameter Dh is smaller than the outer diameter Dk of the blade portion 12 of the drill 10.

  The insertion hole 21 is a portion into which the main body 11 of the drill 10 is inserted at the distal end side (right side in FIG. 3A), and is formed in a circular cross-section and the longitudinal direction of the holder 20 (left-right direction in FIG. 1). ) Linearly. The insertion hole 21 is formed to have a diameter smaller than the outer diameter Db of the main body 11 of the drill 10 at room temperature, and is configured to hold the drill 10 by shrinking the main body 11 of the drill 10. Has been.

  That is, when the holder 20 is heated, the inner diameter of the insertion hole 21 is expanded by thermal expansion, and the main body 11 of the drill 10 can be inserted, while the main body 11 of the drill 10 is inserted. When the holder 20 is cooled, the inner diameter of the insertion hole 21 is reduced by thermal contraction, and the drill 10 can be held so as not to be detached.

  Further, as shown in FIG. 3, an air passage 22 is provided in the outer peripheral surface of the holder 20. The air passage 22 is for sending air into the inside of the machining hole machined in the workpiece as the drill 10 rotates (see FIG. 4), and twists in the direction opposite to the rotation direction of the drill 10 (that is, In the present embodiment, the left twist), a constant lead, and a two-threaded shape with a constant pitch, and the rear end side from the front end surface (the right side surface in FIG. 3A) holding the drill 10 (The left side in FIG. 3 (a)) is extended, and the air passage 22 is opened at the front end surface of the holder 20.

  In a state where the drill 10 is held by the holder 20, the drill 10 is held by the holder 20 so that the opening of the air passage 22 and the groove 13 of the drill 10 are connected (see FIG. 1B).

  It should be noted that the fact that the drill is twisted in the direction opposite to the rotation direction of the drill described in claim 4 is the air passage 22 when the rotation direction of the drill 10 is clockwise as in the present embodiment. Means that the air passage 22 is formed in a right-handed twist.

  Next, with reference to FIG. 4, the method of cutting using the drill unit 1 is demonstrated. FIG. 4 is an explanatory diagram for explaining a method of performing a cutting process using the drill unit 1, and shows a state in which the processing hole H is processed in the workpiece W using the drill unit 1. In FIG. 4, a part of the holder 20 and the workpiece W are viewed in cross section, and the longitudinal direction of the holder 20 (left direction in FIG. 4) is omitted. Further, in FIG. 4, the moving direction of the chips is schematically indicated by an arrow A, and the moving direction of the air fed into the processing hole H is schematically indicated by an arrow B.

  In the case of performing cutting using the drill unit 1 configured as described above, first, the holder 20 is attached to a processing machine via a collet. Next, the workpiece W is cut by the drill unit 1 by the rotational force transmitted from the processing machine.

  At this time, air is sucked into the insertion hole 21 by an intake pump (not shown) connected to the insertion hole 21 of the holder 20, and is generated by the cutting edge 14 of the drill 10 as shown by an arrow A, 13 can be forcibly sucked through the suction path 16 and the sucked chips can be discharged from the rear end of the main body 11 through the holder 20. Therefore, compared with the conventional product, it is possible to suppress (or make unnecessary) the use of the cutting fluid for removing chips, and to prevent environmental pollution.

  Further, since the suction path 16 of the drill 10 is formed by being twisted in the same direction as the rotation direction of the main body part 11, chips can be smoothly moved along the suction path 16 by the rotational force by which the main body part 11 is rotated. Can be discharged. Therefore, it is possible to improve the chip discharging property.

  Further, as described above, the drill 10 is configured such that the outer diameter Db of the main body 11 is smaller than the outer diameter Dk of the blade 12, and the holder 20 into which the main body 11 of the drill 10 is inserted has an outer diameter. Since Dh is configured to be smaller than the outer diameter Dk of the blade portion 12 of the drill 10, the machining hole H to be machined into the workpiece W is longer than the length X of the blade portion 12 in the direction of the axis O of the drill 10. Even in a deep case, the workpiece W and the holder 20 can be normally cut without interference.

  By the way, when the machining hole H is deeper than the length X of the blade portion 12 in the direction of the axial center O of the drill 10, the holder 20 enters the machining hole H, so that the workpiece for sucking air during intake The gap formed between W and the holder 20 is narrow, and the intake resistance increases. On the other hand, since the air passage 22 is recessed in the outer peripheral surface, the holder 20 has a gap formed between the workpiece W and the holder 20 corresponding to the cross-sectional area of the air passage 22. Can be enlarged.

  Therefore, even when the machining hole H is deeper than the length X of the blade portion 12 in the direction of the axis O of the drill 10, as shown by the arrow B, the machining hole H passes through the air passage 22 as the drill 10 rotates. Air can be sufficiently sent into the interior. As a result, it is possible to reduce the intake resistance and improve the intake efficiency.

  Further, the air passage 22 of the holder 20 extends from the front end surface of the holder 20 to the rear end side so as to open to the front end surface of the holder 20, and the drill 10 opens the air passage 22. Since the holder 20 is held on the tip surface side, air can be directly fed into the groove 13 through the air blowing path 22.

  Further, since the air passage 22 of the holder 20 is formed to be twisted in the direction opposite to the rotation direction of the drill 10, air can be forcibly fed through the air passage 22 by the rotational force by which the drill 10 is rotated. .

  Furthermore, since the air passage 22 of the holder 20 is formed in two strips, the amount of air fed into the processing hole H through the blow passage 22 can be increased as compared with the case of one strip. As a result, it is possible to further reduce the intake resistance and further improve the intake efficiency.

  As described above, according to the drill unit 1 of the present invention, the drill 10 is configured such that the suction path 16 is recessed in the outer peripheral surface of the main body 11 and chips are discharged through the suction path 16. Therefore, unlike the conventional product, the main body 11 is configured to be hollow, and the tool rigidity can be ensured and the tool life can be improved as compared with the case where chips are discharged through the main body 11. Can do.

  Further, since the suction path 16 extends to the rear end surface of the main body portion 11 and opens to the rear end surface of the main body portion 11, for example, compared with a case where the suction path 16 opens to the side surface of the main body portion 11. The structure of the holder 20 for discharging can be simplified.

  In addition, the holder 20 and the drill 10 are configured separately, and the drill 10 is held by the holder 20 by shrinking the main body 11 of the drill 10 into the insertion hole 21 of the holder 20. Can be configured. Therefore, only the drill 10 that requires strength can be made of an expensive material, and the tool cost can be reduced as compared with the case where the entire drill unit 1 is made of an expensive material.

  Next, a second embodiment will be described with reference to FIG. Fig.5 (a) is a front view of the drill 30 in 2nd Embodiment, FIG.5 (b) is an expanded sectional view which expands and shows the drill 30 in the Vb-Vb line | wire of Fig.5 (a). is there.

  In the first embodiment, the case where the suction path 16 of the drill 10 is formed by being twisted in the same direction as the rotation direction of the main body 11 has been described. However, in the second embodiment, the suction path 36 of the drill 30 is a shaft. It is formed substantially parallel to the center O. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and the description is abbreviate | omitted.

  Similarly to the drill 10, the drill 30 is held by the holder 20 so that the rotational force of the processing machine is transmitted, and the workpiece is cut (for example, drilled) while rotating by the transmitted rotational force of the processing machine. As shown in FIG. 5, the cutting tool is made of a cemented carbide obtained by pressure-sintering tungsten carbide (WC) or the like. However, the drill 30 is not limited to cemented carbide, and may be made of high-speed tool steel or the like.

  As shown in FIG. 5, the drill 30 has a main body 31, a blade 32 disposed on the distal end side (the right side in FIG. 5A) of the main body 31, and a recess in the outer peripheral surface of the main body 31. The suction path 36 is mainly provided. In the present embodiment, the outer diameter (the diameter of the largest portion of the blade portion 32) Dk of the blade portion 32 is set to 10 mm.

  The main body 31 is a part that is inserted into the insertion hole 21 of the holder 20 and is formed in a columnar shape having an axis O as shown in FIG. The main body 31 is configured such that the diameter Db is smaller than the outer diameter Dk of the blade portion 32. In the second embodiment, the main body 31 is baked into the insertion hole 21 of the holder 20, and the drill 30 is held by the holder 20.

  The blade part 32 is a part for performing a cutting process, and mainly includes a groove 33 and a cutting edge 34 as shown in FIG. The groove 13 is for receiving chips generated by the cutting edge 34, and two grooves 33 a and 33 b are formed substantially parallel to the axis O.

  The cutting edge 34 is a cutting edge formed on the distal end side (right side in FIG. 5A) of the blade portion 32, and relief surfaces 35a and 35b and grooves 33a and 33b formed on the distal end of the blade portion 32 are respectively provided. Two cutting edges 34a and 34b are formed symmetrically with respect to the axis O at each intersecting ridge line portion.

  The suction path 36 is for discharging chips contained in the groove 33. The two suction paths 36a and 36b are formed substantially parallel to the axis O, and the two suction paths are formed. 36a and 36b are connected to the above-mentioned two grooves 33a and 33b, respectively.

  Further, as shown in FIG. 5A, the suction path 36 extends to the rear end surface (the left side surface in FIG. 5A) of the main body 31, and the suction path 36 is the rear end surface of the main body 31. In the state where the drill 30 is held by the holder 20, it is configured to communicate with the insertion hole 21 of the holder 20.

  As described above, according to the second embodiment, since the suction path 36 is formed substantially parallel to the axis O, the structure for discharging chips can be simplified. Therefore, the manufacturing cost of the cutting tool can be reduced.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  For example, although the case where the suction path 16 of the drill 10 is formed in a right-handed twist has been described in the first embodiment, the present invention is not necessarily limited to this, and may be formed in a left-handed twist. However, as described above, the suction path 16 is preferably formed by twisting in the same direction as the rotation direction of the main body portion 11 in order to improve the chip discharging property.

  In the above-described embodiment, the case where the suction paths 16 and 36 of the drills 10 and 30 are formed by leads that are substantially the same as the leads of the grooves 13 and 33 has been described. The leads may be formed with leads different from the leads 13 and 33, or may be formed with unequal leads.

  Moreover, although the said embodiment demonstrated the case where the ventilation path 22 of the holder 20 was formed with a fixed lead, it is not necessarily restricted to this, You may form with an unequal lead.

  Furthermore, although the said embodiment demonstrated the case where the ventilation path 22 of the holder 20 was formed in two strips with a fixed pitch, it is not necessarily restricted to this, You may form with an unequal pitch. Alternatively, the air passages 22 may be formed so as to intersect each other. Moreover, you may form the number of the stripes of the ventilation path 22 in 1 or 3 or more. However, as described above, the air passage 22 is desirably formed in two or more strips in order to improve the chip discharging property.

(A) is a front view of the drill unit in 1st Embodiment of this invention, (b) is an enlarged side view which expands and shows the drill unit in the arrow Ib direction view of Fig.1 (a). . (A) is a front view of a drill, (b) is an enlarged side view which expands and shows the drill in the arrow IIb direction view of Fig.2 (a). (A) is a front view of a holder, (b) is an enlarged side view showing the holder in an arrow IIIb direction view of FIG. It is explanatory drawing explaining the method of cutting using a drill unit. (A) is a front view of the drill in 2nd Embodiment, (b) is an enlarged side view which expands and shows the drill in the arrow IVb direction view of Fig.5 (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drill unit 10,30 Drill 11,31 Main-body part 12,32 Blade part 13,33 Groove 14,34 Cutting edge 16,36 Suction path 20 Holder 21 Insertion hole 22 Blower path O Axis center

Claims (8)

A drill having a main body rotated about an axis, a blade disposed at a tip of the main body and having a cutting edge, and a groove provided on the blade and forming a rake face of the cutting edge; A drill unit for holding the drill by the holder, comprising a holder having an insertion hole into which the main body of the drill is inserted, and shrinking the main body of the drill into the insertion hole of the holder,
The drill includes a suction path that is recessed in the outer peripheral surface of the main body, is provided continuously with the groove, and extends to a rear end surface of the main body, and the outer diameter of the main body is the blade portion. Configured to be smaller than the outer diameter of
The holder includes an air passage recessed in the outer peripheral surface, and the outer diameter is configured to be smaller than the outer diameter of the blade portion of the drill,
The suction hole is inserted into the insertion hole of the holder so that the chips generated by the cutting edge of the drill and accommodated in the groove are sucked through the suction path and discharged from the rear end of the main body. The drill unit is characterized by being made.   The drill unit according to claim 1, wherein the suction path of the drill is formed by being twisted in the same direction as the rotation direction of the main body.   The air passage of the holder extends from the front end surface to the rear end side of the holder so as to be opened at the front end surface of the holder, and the drill is connected to the holder in which the air passage is opened. The drill unit according to claim 1 or 2, wherein the drill unit is held on a tip surface side.   The drill unit according to any one of claims 1 to 3, wherein the air passage of the holder is formed by being twisted in a direction opposite to a rotation direction of the drill.   The drill unit according to claim 4, wherein the air passages of the holder are formed in multiple lines.   The length of the said blade part to the said axial direction of the said drill is set to the length of 50% or more of the diameter of the said blade part, and 150% or less from Claim 1 characterized by the above-mentioned. The drill unit according to claim 5.   The drill used for the drill unit in any one of Claim 1 to 6. The holder used for the drill unit in any one of Claim 1 to 6.

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