JP5923646B1 - Shrink-fitting tool holder and cutter chucking structure - Google Patents

Abstract

The present invention provides a shrink-fit tool holder that is improved over the prior art. A shrink-fit tool holder (10) includes a holder body (11) and a shank portion (61) of a blade (60) provided in a tip region of the holder body and inserted into a tool holding hole (122). Of these, the cylindrical region (61c) having an outer peripheral surface with a constant radius on the front end side of the rear end portion of the shank portion is shrink-fitted over a predetermined effective grasping length so that the axis of the cutter coincides with the axis of the holder body. A cylindrical shrink-fit detachable portion (12) for grasping and centering, a through hole (22) provided on the rear end side in the axial direction from the fit detachable portion and extending from the outer peripheral surface of the holder body to the tool holding hole, and A side lock type attaching / detaching portion (21) having a side lock bolt (23) screwed into the through hole is provided. The through hole extends at an angle of 1 to 10 degrees with respect to the direction perpendicular to the axis so that the outer diameter side is closer to the front end side in the axis (O) direction than the inner diameter side. [Selection] Figure 2

Description

  The present invention relates to a shrink-fit tool holder that chucks a shank portion of a cutter that cuts a difficult-to-cut material such as a titanium alloy for a long period of time while securely retaining and preventing rotation.

  2. Description of the Related Art Conventionally, many shrink-fit tool holders that chuck a blade using the thermal contraction and thermal expansion of a tool holder main body are known.

  In recent years, in the aircraft field and the like, it has been required to cut difficult-to-cut materials such as titanium alloys and Inconel (registered trademark) for a long time. When cutting difficult-to-cut materials for a long time, even if the tool is securely chucked with the tool holder, the tool will come out of the shrink-fit tool holder compared to cutting with a soft aluminum material. There was a problem to come.

  As a conventional technique for solving such a problem, as a tool holder that has a cylindrical tool holding hole that expands or contracts due to a heat change and chucks a shank portion of a blade by shrink fitting, for example, re-published patent WO2013 / 027558 The thing of patent document 1 is known. The shrink-fit tool holder of Patent Document 1 includes a cylindrical holding hole formed in the shrink-fit chuck portion, and two retaining protrusions formed on the inner peripheral surface of the cylindrical holding hole and facing each other. And a rotation stopper protrusion formed on the inner peripheral surface of the cylindrical holding hole on the rear end side in the axial direction with respect to each protrusion stopper. By inserting the shank of the cutting tool deeply into the cylindrical holding hole and rotating it slightly in the circumferential direction, each retaining projection enters the circumferential groove of the cutting tool, and each rotation preventing projection is a flat surface of the cutting tool. Abut.

  The chucking of the cutting tool to the shrink-fit tool holder of Patent Document 1 is performed in a state where the shrink-fit chuck portion of the tool holder is heated and thermally expanded to expand the cylindrical holding hole. When the shrink-fit tool holder is cooled, the cutting-out protrusion is locked to the edge of the circumferential groove, and the cutting tool is placed in the shrink-fit tool holder with the anti-rotation protrusion in contact with the end of the flat surface. While being chucked by shrink fitting, it is possible to prevent the cutting tool from coming off and to prevent rotation with respect to the shrink fitting chuck portion.

  The cutting tool is removed from the shrink-fit tool holder by heating and shrinking the shrink-fit tool holder to expand the cylindrical holding hole and then rotating and pulling the cutting tool in reverse to the above procedure. It is.

Republished patent WO2013 / 027558

  However, the shrink-fit tool holder of Patent Document 1 still causes problems as described below. That is, since the width dimension of the retaining protrusion is slightly smaller than the groove width of the circumferential groove, there is a possibility that rattling occurs between them. Moreover, in the rotation stopping structure of the shrink-fit tool holder of Patent Document 1, it does not rotate in one direction but rotates in the other direction. In particular, since the cutting tool rotates in the other direction due to fine vibration during cutting, the cutting tool cannot be reliably prevented from rotating.

  In view of the above circumstances, an object of the present invention is to provide a shrink-fit tool holder that can reliably prevent a cutter from coming off and prevent rotation, and that does not cause rattling of the cutter.

For this purpose, the shrink-fit tool holder according to the present invention is a round hole extending from the front end in the axial direction toward the rear end side in the axial direction, and a tool holding hole for shrink-fitting the shank portion of the blade, the tool holding hole. A large-diameter portion having a diameter larger than that of the tool holding hole and extending further toward the rear end side in the axial direction through which the rear end portion of the shank portion of the blade inserted into the tool holding hole passes. A holder body having a small-diameter hole than the diameter part and extending from the large-diameter part further toward the rear end side in the axial direction and receiving the rear end part of the shank part of the cutter, and the axial direction of the holder body The axis of the cutter is the axis of the holder body with respect to a cylindrical region having an outer peripheral surface having a constant radius on the tip side of the shank portion of the shank portion provided in the tip region and inserted into the tool holding hole. To match A cylindrical shrink-fit detachable part that is grasped and centered by shrink fitting over a fixed effective grasping length, and one or more locations on the rear end side in the axial direction from the shrink-fit detachable part. It has a through hole extending to the holding hole, and one or more side lock bolts screwed into the through hole. The side lock bolt extends by tilting at a predetermined angle of 10 degrees or less, and the side lock bolt is screwed toward the tool holding hole in a state where the cylindrical region of the shank portion of the blade is grasped and centered by the shrink fitting and attaching portion. The flat pressing surface provided at the tip of the lock bolt is brought into contact with the inclined flat surface provided on the outer periphery of the rear end portion of the shank portion of the blade to press the flat surface, and the pressing force is small. Comprising a side-locking detachable portion inner peripheral surface of the part is to impart a reaction force to the outer peripheral surface of the rear end portion of the shank portion of the tool, the. And the shank part of a cutter is chucked by these shrink-fitting type attaching / detaching parts and side lock type attaching / detaching parts.

According to the present invention, the shrink-fit tool attaching / detaching portion is in a cylindrical region of the shank portion of the blade,
Since centering is performed by shrink fitting over a predetermined effective grasping length, the axis of the holder body coincides with the axis of the cutter, and the cutter can be grasped with high accuracy. Further, a strong frictional force is exerted over a predetermined effective grasp length between the inner peripheral surface of the tool holding hole and the outer peripheral surface of the cylindrical region, and the cutter does not easily come out during the cutting process. After this, the side lock bolt reliably prevents the shank portion of the blade from coming off and rotating as a final tightening function. By these shrink-fit tool attaching / detaching portions and side lock type attaching / detaching portions, even when a difficult-to-cut material is cut for a long time, the chucking of the blade is not loosened.

  When an operator inserts the shank part of the tool into the tool holding hole of the tool holder, be careful that the flat surface provided on the outer periphery of the rear end part of the shank part faces the side lock bolt of the side lock type attaching / detaching part. Must be plugged in. Since the shank part of the cutter is basically cylindrical, if the rear end part of the shank part is inserted into the tool holding hole, the circumferential position of the flat surface formed in the shank part cannot be seen. is there. As a preferred embodiment, a marking is provided at a circumferential position corresponding to the through hole at the axial end of the holder body. According to this embodiment, when inserting the shank portion of the blade into the tool holding hole, the operator only needs to insert the flat surface of the rear end of the shank portion in accordance with the marking on the tip portion of the tool holder, thereby improving the chucking work efficiency. To do.

  The number of side lock bolts may be one or more. As a preferred embodiment of the first invention, the through-holes of the side lock type attaching / detaching portion are provided with first and second through-holes provided at two locations separated by a predetermined angle of 60 degrees or more and 120 degrees or less in the circumferential direction of the holder body. The side lock bolt includes a first side lock bolt that is screwed into the first through hole, and a second side lock bolt that is screwed into the second through hole. According to this embodiment, since the pressing force applied to the shank portion by the first side lock bolt and the pressing force applied to the shank portion by the second side lock bolt intersect each other, the shank portion is connected to the inner peripheral surface of the holder body. The centering accuracy is maintained by suitably pressing to the center. Further, since the two side lock bolts are used, the pull-out function and the anti-rotation function are improved. As a more preferred embodiment, the first through hole is provided at a position away from the second through hole by a predetermined angle of 80 degrees or more and 100 degrees or less in the circumferential direction of the holder body. As a further preferred embodiment, the first through hole is provided at a position 90 degrees away from the second through hole in the circumferential direction of the holder body.

  When the angle between the first through hole and the second through hole is less than 60 degrees, the force for pressing the shank portion in a specific radial direction is increased, and the centering accuracy is not maintained. Further, when the angle between the first flat surface and the second flat surface exceeds 120 degrees, the resultant force of the force that the first flat surface receives from the side lock bolt and the force that the second flat surface receives from the side lock bolt is The ratio which cancels increases and the force which presses a shank part in a radial direction toward a tool holder will become weak.

  As a preferred embodiment of the present invention, the side lock bolt includes a bolt body that is screwed into the through-hole, and a pressing member that is formed so that the pressing surface is formed and the direction of the pressing surface can be changed at the tip of the bolt body. Including. According to this embodiment, even if the advancing direction of the side lock bolt is not orthogonal to the flat surface of the shank portion of the blade, when the side lock bolt is screwed and rotated in the tightening direction, the pressing surface at the end of the side lock bolt becomes the shank. The direction is changed to follow the flat surface of the part, and the flat surface is brought into surface contact. Therefore, the side lock bolt firmly presses the flat surface of the shank portion, and the shank portion can be chucked more reliably. As another embodiment of the present invention, the pressing surface may be formed at the tip of the bolt body.

  As a further preferred embodiment of the present invention, there is further provided a stopper which is provided on the bottom side of the tool holding hole and which defines the axial position of the shank portion of the cutter inserted into the tool holding hole. According to this embodiment, the shank part of a cutter does not retreat carelessly along a tool holding hole, and the flat surface of a shank part can be reliably pressed down with the pressing surface of a side lock bolt. The stopper of the present invention may be a part of the holder main body, or may be a component housed inside the holder main body.

  The position of the stopper is preferably adjustable, and as an embodiment of the present invention, the stopper is a member accommodated on the bottom side of the tool holding hole and can be replaced with either a long stopper or a short stopper. According to this embodiment, by replacing the short stopper with the long stopper, the re-polished short cutter is pulled out to the tip side and protruded from the tip of the shrink-fit tool holder by the same length as the new cutter. be able to.

  As one embodiment of the present invention, a female screw extending from the bottom of the tool holding hole to the rear end side in the axial direction of the bolt body, and a preloading bolt that is screwed into the female screw and applies a pressing force in the distal direction to the shank portion of the blade Is further provided. According to this embodiment, the surface pressure increases between the pressing surface of the side lock bolt and the inclined flat surface of the shank portion. Therefore, the retaining effect and the anti-rotation effect by the side lock type attaching / detaching portion are strong. The preload bolt may apply a pressing force in the distal direction to the shank portion of the blade through a stopper accommodated on the bottom side of the tool holding hole. Alternatively, the preload bolt may directly apply a pressing force in the tip direction to the shank portion of the blade without using a stopper.

  As one embodiment of the present invention, the stopper and the preloading bolt have a connecting passage penetrating in the axial direction, and the connecting passage is configured to be connected to the rear end opening of the liquid passage provided in the shank portion of the blade. According to this embodiment, the cutting fluid flows through the shrink-fit tool holder and the blade and is supplied to the workpiece, so that the cutting performance is improved.

The shank structure of the cutter according to the present invention includes the above-described shrink-fit tool holder and the shank portion of the cutter inserted into the tool holding hole, and the shank portion is formed at one or more locations on the outer periphery of the rear end portion of the shank portion. A flat surface that comes into contact with the pressing surface of the side lock bolt, and a columnar region that is formed on the tip side of the flat surface and is tightened to the shrink-fitting detachable portion and has a length that is equal to or greater than a predetermined effective grasping length. The flat surface is inclined so as to be directed toward the front end side in the axial direction at a predetermined angle of 1 to 10 degrees with respect to the axis of the shank portion. According to this embodiment, the shank portion of the blade is grasped and centered with a sufficient effective grasping length by the shrink-fit tool attaching / detaching portion of the shrink-fit tool holder. Then, the side lock type attaching / detaching portion of the shrink-fit type tool holder securely and securely prevents the rotation and the rotation.

  A flat surface may be provided in one place of a blade shank part, or may be provided in a plurality of places. As one embodiment of the present invention, the flat surface of the blade shank part includes first and second flat surfaces formed at two locations separated by a predetermined angle of 60 degrees or more and 120 degrees or less in the circumferential direction of the shank part. The first flat surface contacts the pressing surface of the first side lock bolt among the side lock bolts, and the second flat surface contacts the pressing surface of the second side lock bolt among the side lock bolts. According to such an embodiment, the pressing force applied to the first flat surface and the pressing force applied to the second flat surface intersect each other, and the shank portion is suitably pressed against the inner peripheral surface of the tool attaching / detaching portion. The centering accuracy is maintained. In addition, since it has two inclined flat surfaces, the function of pulling out the shank portion and the function of preventing rotation are improved.

As one embodiment of the present invention, a liquid passage extending from the shank portion of the blade to the blade portion of the blade is further provided. According to this embodiment, the cutting fluid flows through the inside of the blade and is supplied to the cutting portion of the workpiece, so that the cutting performance is improved.

  Thus, according to the present invention, the centering accuracy, the anti-rotation function, and the retaining function are improved as compared with the conventional shrink-fit tool holder. Moreover, the shakiness of the cutter in the axial direction, which is a concern in Patent Document 1, is prevented, and highly accurate cutting can be performed.

1 is an overall view showing a shrink-fit tool holder according to a first embodiment of the present invention. It is a longitudinal cross-sectional view which expands and shows the front-end | tip area | region of 1st Embodiment. It is a front view which shows the axial direction front-end | tip part of 1st Embodiment. It is a longitudinal cross-sectional view which expands and shows the front-end | tip area | region of 1st Embodiment. It is a general view which shows the cutter cut by 1st Embodiment. It is a general view which shows the cutter of a modification. It is a cross-sectional view which shows 1st Embodiment with the rear-end part of a blade shank part. It is a longitudinal cross-sectional view which expands and shows the front-end | tip area | region of the shrink fitting tool holder which becomes 2nd Embodiment of this invention. It is a front view which shows the axial direction front-end | tip part of 2nd Embodiment. It is a longitudinal cross-sectional view which expands and shows the front-end | tip area | region of 2nd Embodiment. It is a whole view which shows the cutter cut by 2nd Embodiment. It is a cross-sectional view which shows 2nd Embodiment with the rear-end part of a blade shank part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall view showing a shrink-fit tool holder according to the first embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the tip region of the first embodiment, and shows a state taken along the line II-II in FIG. FIG. 3 is a front view showing the tip portion in the axial direction of the first embodiment. For reference, FIG. 2 shows a cutter inserted into the tool holding hole of the shrink-fit tool holder. The shrink-fit tool holder 10 includes a holder body 11 and side lock bolts 23 as main components.

  The metal holder main body 11 extends along an axis O indicated by a one-dot chain line, and a shrink-fit tool attaching / detaching portion 12 for chucking a cutter in the tip end region of the holder main body 11 in the axis O direction, and an axis O of the holder main body 11. And a mounting portion 13 mounted on the spindle of the machine tool in the rear end region. A large-diameter flange portion 14 is formed in the center portion of the holder main body 11 in the direction of the axis O so as to protrude from the tool attaching / detaching portion 12 and the mounting portion 13 in the outer diameter direction. A V-shaped groove 142 extending in the circumferential direction is formed on the outer peripheral edge of the flange portion 14.

  The mounting portion 13 has a shape that fits into a main shaft of a machine tool (not shown), and the outer peripheral surface of the mounting portion 13 of this embodiment is formed in a taper that decreases in radius toward the rear end in the axial direction. The mounting portion 13 is formed with a pull stud attachment hole 132 extending along the axis O that becomes the center of the holder body 11. A female thread 132t is formed on the inner periphery of the rear end of the pull stud mounting hole 132, and the female thread 132t extends from the rear end of the holder body 11 in the axis O direction toward the front end side in the axis O direction. The bottom of the pull stud mounting hole 132 is connected to the communication hole 133. The communication hole 133 extends along the axis O, and is connected to an intermediate hole 123 described later on the tip side in the axis O direction.

  A pull stud (not shown) is screwed into the female screw 132t, and the pull stud is pulled backward, whereby the mounting portion 13 is securely mounted to the center through coolant main shaft of the machine tool. Then, the cutting fluid or the cleaning fluid flows into the pull stud mounting hole 132 from the center through coolant main shaft. Therefore, the pull stud attachment hole 132, the communication hole 133, and the intermediate hole 123 become a liquid passage.

  The tool attaching / detaching portion 12 has a thick cylindrical shape made of metal with an opening in the axial direction, and has an outer peripheral surface 12g and an inner peripheral surface 12h. The inner peripheral surface 12h defines a tool holding hole 122 that extends along the axis O from the axial front end toward the axial rear end. As indicated by a two-dot chain line in FIG. 2, the shank portion 61 of the blade 60 is inserted into the tool holding hole 122 as indicated by a two-dot chain line in FIG. 2. The inner peripheral surface 12h of the tool holding hole 122 has an effective grasping length L of a predetermined dimension, and its inner diameter is slightly smaller than the outer diameter of the shank portion of the cutter inserted into the tool holding hole 122 (shank portion outer dimension− 0.03 mm or more and -0.025 mm or less). For example, when the outer diameter of the shank portion 61 is 20.00 mm, the inner diameter of the inner peripheral surface 12 h is 20.00−0.03 mm or more and 20.00−0.025 mm or less in a cooled state where the shank portion 61 is not inserted. It is. However, when the tool attaching / detaching portion 12 is sufficiently heated, the inner diameter of the inner peripheral surface 12h becomes slightly larger than the outer diameter of the shank portion of the cutter.

  The tool holding hole 122 is connected to the large diameter portion 122b of the tool holding hole on the bottom side. 2, the rear end portion of the shank portion 61 is inserted into the large diameter portion 122b. Even in the state where the tool attaching / detaching portion 12 is cooled, the inner diameter of the large diameter portion 122b is larger than the outer diameter of the shank portion of the cutter inserted into the tool holding hole 122. The large diameter portion 122b extends along the axis O, and is connected to the small diameter portion 122s of the tool holding hole on the rear end side in the axis O direction.

  As shown by a two-dot chain line in FIG. 2, the rear end portion of the shank portion 61 is inserted into the small diameter portion 122s. Even in the state where the tool attaching / detaching portion 12 is cooled, the inner diameter of the small diameter portion 122s is slightly larger than the outer diameter of the shank portion of the cutter (range of the shank portion outer dimension + 0.01 mm or more + 0.02 mm or less). For example, when the outer diameter of the shank portion 61 is 20.00 mm, the inner diameter of the small diameter portion 122s is 20.00 + 0.01 mm or more and 20.00 + 0.02 mm or less. The small diameter portion 122s extends along the axis O, and is connected to the intermediate hole 123 on the rear end side in the axis O direction. When the rear end portion of the shank portion 61 is pressed in the inner diameter direction by a side lock bolt 23 to be described later, the inner peripheral surface of the small diameter portion 122s is polished, and the shank is positioned 180 degrees away from the side lock bolt 23 in the circumferential direction. The rear end part outer peripheral surface of the part 61 is received.

  The inner diameter of the intermediate hole 123 is slightly larger than the inner diameter of the small diameter portion 122s. The intermediate hole 123 extends along the axis O and is connected to the tip of the communication hole 133 on the rear end side in the axis O direction. Since the intermediate hole 123 has an inner diameter larger than that of the communication hole 133, an annular step 124 is formed at the connection point between the intermediate hole 123 and the communication hole 133 so as to be directed to the tip side in the axis O direction. A female screw 133 t is formed on the inner periphery of the communication hole 133. The female screw 133t is disposed on the front end side in the axis O direction and is adjacent to the annular step 124. The intermediate hole 123 accommodates a stopper 25 described later. The stopper 25 has a flat front end surface 251 and a flat rear end surface 252. The annular step 124 abuts against the rear end surface 252 of the stopper 25 to restrict the backward movement of the stopper 25.

  The outer peripheral surface 12g of the tool attaching / detaching portion 12 is slightly tapered so as to become thinner toward the front end side in the axis O direction. The tool attaching / detaching portion 12 has an effective grasping length L of at least a predetermined dimension, and when heated, the inner diameter of the tool holding hole 122 is expanded by thermal expansion and becomes slightly larger than the outer diameter of the shank portion of the blade.

  A through hole 22 extending through the holder body 11 in the radial direction is formed on the rear end side of the tool attaching / detaching portion 12. The outer peripheral surface of the holder main body 11 has a taper shape with a gentler gradient than the outer peripheral surface 12 g on the rear end side in the axis O direction with respect to the through hole 22. The inner diameter end of the through hole 22 is connected to the small diameter portion 122s. Or it connects with small diameter part 122s and large diameter part 122b. The inner diameter end of the through hole 22 is located closer to the rear end side in the axis O direction than the outer diameter end of the through hole 22. For this reason, the through hole 22 extends with an inclination of 5 degrees with respect to a straight line orthogonal to the axis O. Or the through-hole 22 inclines and extends by the predetermined angle included in the range of 1 degree or more and 10 degrees or less. A marking 24 is provided at the tip of the outer peripheral surface 12 g at the same circumferential position as the through hole 22. The marking 24 may be engraved or printed. The marking 24 is further provided on the front end surface of the holder main body 11, that is, the front end surface of the tool attaching / detaching portion 12. Thereby, the circumferential position of the through hole 22 is easily visually recognized from the tip side of the tool holder 10.

  A female screw 221 is formed on the inner peripheral surface of the through hole 22, and the side lock bolt 23 is screwed together. The side lock bolt 23 has a flat holding surface 231 orthogonal to the axis of the side lock bolt 23 at the front end and a polygonal hole 232 for engaging with a wrench at the rear end. When a wrench (not shown) is engaged with the polygonal hole 232 and tightened and rotated so as to screw the side lock bolt 23, the side lock bolt 23 advances toward the small diameter portion 122s. Conversely, when the side lock bolt 23 is loosened and rotated, the side lock bolt 23 moves backward from the small diameter portion 122s. The holding surface 231 is directed toward the inner diameter side of the holder body 11, and the polygonal hole 232 is directed toward the outer diameter side of the holder body 11. The through hole 22 and the side lock bolt 23 constitute a side lock type attaching / detaching portion 21 for chucking the blade.

  The pressing surface 231 may be formed on the main body of the side lock bolt 23, but in the first embodiment, the side lock bolt 23 includes a bolt main body 233 and a pressing member 234. The bolt body 233 has a polygonal hole 232 at the rear end and a male screw 235 on the outer peripheral surface. A spherical recess is formed at the tip of the bolt body 233, and a ball-shaped pressing member 234 is fitted into the recess. The pressing member 234 has a flat pressing surface 231 formed at the tip thereof. Thus, since the pressing member 234 is supported by the bolt body 233 on the spherical surface, the pressing surface 231 can rotate around the central axis of the bolt main body 233 and be inclined with respect to the central axis of the bolt main body 233. Can do. Therefore, the direction of the pressing member 234 can be freely changed with respect to the bolt body 233. Further, the pressing member 234 may be attached to the bolt main body 233 as long as the direction can be freely changed as shown in FIG.

  The shrink-fit tool holder 10 according to the first embodiment further includes a preload bolt 27 that applies preload to a shank portion of a cutter inserted into the tool holding hole 122. The preload bolt 27 is screwed with the female screw 133t of the communication hole 133, and can advance and retreat in the direction of the axis O. A flat pressing surface 271 orthogonal to the axis O is formed at the tip of the preload bolt 27, and the pressing surface 271 contacts the stopper 25. A polygonal hole 272 for engaging with the wrench is formed at the rear end of the preload bolt 27. When a wrench (not shown) is inserted into the pull stud mounting hole 132 and engaged with the polygonal hole 272 and tightened and rotated so that the preload bolt 27 is screwed, the preload bolt 27 advances toward the intermediate hole 123. Conversely, when the preload bolt 27 is loosened and rotated, the preload bolt 27 moves backward from the intermediate hole 123. The preload bolt 27 is screwed in the distal direction, thereby pressing the stopper 25 in the distal direction.

  Next, the cutter that is chucked on the shrink-fit tool holder 10 will be described.

  FIG. 5 is a side view showing a cutter according to an embodiment of the present invention. The steel blade 60 has a super steel alloy blade 60b in the axial front end region, a shank portion 61 in the axial rear end region, and extends along the axis indicated by the alternate long and short dash line. The shank portion 61 is basically a cylindrical shape having a circular cross section with a constant radius. However, a flat surface 62 is formed at one place in the circumferential direction on the outer periphery of the rear end portion of the shank portion 61 by cutting. Of the shank portion 61, the length dimension of the cylindrical region 61c on the tip side of the flat surface 62 has at least an effective grasping length L and an outer peripheral surface having a constant radius. The blade 60 is an end mill, but may be a drill or a reamer.

  The flat surface 62 is disposed at the rear end portion in the axial direction of the shank portion 61, and is adjacent to the rear end surface 64 that is a flat surface orthogonal to the axial line of the shank portion 61. The flat surface 62 is not parallel to the axis O of the shank portion 61 but is slightly inclined at a predetermined angle so as to be directed toward the distal end side of the blade 60. The predetermined angle is 5 degrees with respect to the axis of the shank portion 61. Alternatively, the flat surface 62 is a surface inclined within a range of 1 degree to 10 degrees. The predetermined angle of the flat surface 62 may correspond to the inclination angle of the through hole 22 described above.

  Next, the chucking of the blade 60 will be described.

  At the time of chucking, the tool attaching / detaching portion 12 is heated to a predetermined temperature, the diameter of the tool holding hole 122 is expanded by thermal expansion, and the shank portion 61 of the cutter 60 is moved from the tip side of the shrink-fit tool holder 10 to the tool holding hole 122. By plugging in. When inserting, the flat surface 62 of the shank part 61 is matched with the marking 24 of the tool attaching / detaching part 12. By firmly inserting the shank portion 61, the rear end face 64 of the shank portion 61 comes into contact with the stopper 25. The stopper 25 defines the position in the axis O direction of the shank portion 61 of the cutter 60 inserted into the tool holding hole 122. The stopper 25 is a member different from the holder main body 11. However, as a modification (not shown), the stopper 25 may be integrally formed with the holder main body 11. Alternatively, as a modification (not shown), the stopper 25 may not be installed, and the pressing surface 271 of the preload bolt 27 may be brought into contact with the rear end surface 64 of the shank portion 61 described later. In such a modification, the preload bolt 27 serves as a stopper.

  After that, when the tool attaching / detaching portion 12 is cooled and thermally contracted, the tool holding hole 122 is reduced in diameter, and the inner peripheral surface 12h uniformly tightens the outer peripheral surface of the shank portion 61 over the entire periphery, thereby effectively grasping the shank portion 61. Grasp closely and firmly over the length L. Further, the shank part 61 is centered so that the axis of the shank part 61 coincides with the axis O of the shrink-fit tool holder 10.

  Next, the side lock bolt 23 of the side lock type attaching / detaching portion 21 is screwed toward the small diameter portion 122 s, and the pressing surface 231 of the side lock bolt 23 comes into surface contact with the flat surface 62 of the shank portion 61. As a result, the shank portion 61 is prevented from coming off and prevented from rotating. At this time, as indicated by an arrow in FIG. 7, the pressing surface 231 at the tip of the side lock bolt 23 presses the flat surface 62, and the rear end portion of the shank portion 61 receives a pressing force in the inner diameter direction. At the same time, the inner peripheral surface of the small diameter portion 122 s comes into surface contact with the outer peripheral surface of the rear end portion of the shank portion 61 to receive the pressing force from the side lock bolt 23. Specifically, as indicated by arrows in FIG. 7, the inner peripheral surface of the small diameter portion 122 s is counteracted in the inner diameter direction at the rear end portion outer peripheral surface of the shank portion 61 at a position 180 degrees away from the through hole 22 in the circumferential direction. Is granted. Thus, the axis of the shank portion 61 is held so as not to deviate from the axis O of the tool holder body.

  Next, the bolt 27 is screwed in, a preload in the front end direction is loaded on the stopper 25, and the rear end face 64 of the shank portion 61 is pressed through the stopper 25. This not only increases the surface pressure between the front end surface 251 of the stopper 25 and the rear end surface 64 of the shank portion 61, but also increases the surface pressure between the pressing surface 231 of the side lock bolt 23 and the flat surface 62 of the shank portion 61. As a result, the retaining effect and the detent effect of the side lock type attaching / detaching portion 21 are improved.

  When releasing the chucking of the blade 60, a procedure reverse to the procedure described above may be performed. When the bolt 27 is loosened and rotated, the side lock bolt 23 is loosened and rotated, the tool attaching / detaching portion 12 is heated to a predetermined temperature, the tool holding hole 122 is expanded, and the shank portion 61 is pulled out from the tool holding hole 122 in the distal direction. Good.

  The blade portion 60b of the blade 60 is regenerated by re-polishing when worn by use. If it does so, the blade length of the blade part 60b will become shorter than before grinding | polishing. Therefore, as shown in FIG. 4, the stopper 25 that is short in the direction of the axis O may be replaced with a long stopper 26. As a result, the re-polished blade portion 60b can be pulled out to the tip side and protrude from the tip of the shrink-fit tool holder by the same length as the new blade 60. In consideration of the fact that the flat surface 62 advances toward the tip of the axis O after re-polishing, the flat surface 62 is larger than the pressing surface 231 and may be formed so as to expand toward the rear end of the axis O when new. desirable.

  As a modification of the cutter 60 shown in FIG. 5, as shown in FIG. 6, a cutter 65 further provided with a liquid passage 66 may be chucked on the shrink-fit tool holder 10. The liquid passage 66 extends in the axial direction from the front end of the blade 65 to the rear end face 64. Since the other configuration of the blade 65 is the same as that of the blade 60 described above, a common reference numeral is assigned and description thereof is omitted. A communication passage 253 that penetrates in the direction of the axis O is formed in the stopper 25. The bolt 27 is also formed with a communication passage 273 that penetrates in the direction of the axis O. The communication passages 253 and 273 extend along the axis O. When the front end surface 251 of the stopper 25 is in surface contact with the rear end surface 64 of the shank portion 61, the communication passages 253 and 273 and the rear end opening of the liquid passage 66 are connected to each other.

  While the shrink-fit tool holder 10 rotates at high speed about the axis O and cuts a workpiece (not shown) with the blade 65, the rear of the liquid passage 66 passes through the communication passages 273 and 253 from the connection hole 133 of the holder body 11. Cutting fluid is supplied to the end. The cutting fluid flows through the liquid passage 66 and is ejected from the tip (not shown) of the blade 65 to reach the workpiece.

  By the way, the shrink-fit tool holder 10 of the first embodiment is provided in the holder main body 11 having a tool holding hole 122 extending from the front end in the axis O direction toward the rear end side in the axis O direction, and in the front end region of the holder main body 11. The cylindrical area 61c of the shank 61 of the cutter 60 inserted into the tool holding hole 122 is grasped and centered by shrink fitting over a predetermined effective grasping length L so that the axis of the cutter 60 coincides with the axis O of the holder body. A cylindrical tool attaching / detaching portion 12, a through hole 22 provided on the rear end side in the axis O direction from the tool attaching / detaching portion 12, and extending from the outer peripheral surface of the holder body 11 to the large diameter portion 122b of the tool holding hole, and the through hole The side lock bolt 23 is screwed to the side lock bolt 23, and a flat pressing surface 231 provided at the tip of the side lock bolt 23 is provided on the outer periphery of the rear end portion of the shank portion 61. It provided with a side locking detachable portion 21 to abut against the flat surface 62 which is inclined that. The through hole 22 is inclined and extended at a predetermined angle of 1 degree or more and 10 degrees or less with respect to a direction perpendicular to the axis O so that the outer diameter side is closer to the distal end side in the axis O direction than the inner diameter side. When the cylindrical region 61c of the shank portion 61 of the blade 60 is grasped and centered by the tool attaching / detaching portion 12, it is screwed toward the small diameter portion 122s so that the holding surface 231 at the tip of the side lock bolt is inclined at the rear end of the shank portion. The flat surface 62 is brought into contact. The shrink-fit tool holder 10 chucks the shank portion 61 of the blade 60 by using the tool attaching / detaching portion 12 and the side lock attaching / detaching portion 21.

  According to the first embodiment, since the tool attaching / detaching portion 12 centers the shank portion 61 of the cutter 60, the axis O of the holder main body 11 and the axis of the cutter 60 coincide with each other, and the cutter 60 can be grasped with high accuracy. Can do. Further, a strong frictional force is exerted over the effective grasp length L between the inner peripheral surface 12h of the tool attaching / detaching portion 12 and the outer peripheral surface of the cylindrical region 61c of the shank portion 61, and the cutter 60 is easily pulled out during the cutting process. Absent. Thereafter, the side lock bolt 23 prevents the shank portion 61 of the blade 60 from coming off and preventing it from rotating as a final tightening function. The shrink-fitting tool attaching / detaching part 12 and the side lock attaching / detaching part 21 prevent the chucking from loosening even if the difficult-to-cut material is cut for a long time.

  Further, the side lock bolt 23 of the first embodiment is formed with a bolt main body 233 that is screwed into the through hole 22 and a pressing surface 231 that comes into contact with the flat surface 62 of the blade 60, and a pressing surface 231 at the tip of the bolt main body 233. The pressing member 234 is attached so that the orientation of the can be changed freely. According to such an embodiment, even if the advancing direction of the side lock bolt 23 is not perpendicular to the flat surface 62 of the shank portion 61, if the side lock bolt 23 is screwed and rotated in the tightening direction, the pressing surface of the end of the side lock bolt 231 changes its direction following the flat surface 62 of the shank portion 61 and comes into surface contact with the flat surface 62. Therefore, the side lock bolt 23 firmly presses the flat surface 62 of the shank portion 61, and the shank portion 61 can be chucked more reliably.

  The shrink-fit tool holder 10 of the first embodiment further includes a stopper 25 that is provided on the bottom side of the tool holding hole 122 and that defines the axial position of the shank portion 61 inserted into the tool holding hole 122. Thus, the flat surface of the shank portion 61 can be reliably pressed by the pressing surface 231 without the cutter 60 retreating carelessly along the tool holding hole 122.

  Further, the shrink-fit tool holder 10 of the first embodiment is screwed into a connecting hole 133 extending from the bottom of the tool holding hole 122 to the rear end side in the axial direction of the holder body 11 and a female screw 133t of the connecting hole 133. Since the preload bolt 27 for applying a pressing force in the distal direction to the 60 shank portions is further provided, the surface pressure increases between the pressing surface 231 of the side lock bolt 23 and the inclined flat surface 62 of the shank portion 61. . Therefore, the retaining effect and the detent effect by the side lock type attaching / detaching portion 21 are strong.

  Further, the stopper 25 and the preload bolt 27 of the first embodiment have connecting passages 253 and 273 penetrating in the direction of the axis O, and the connecting passage 253 is a liquid passage 66 provided in the shank portion of the blade 65 (FIG. 6). Since it is configured to be connected to the rear end opening, the cutting fluid flows through the shrink-fit tool holder 10 and the blade 65 and is supplied to the workpiece, thereby improving the cutting performance.

  Further, the blade 60 of the first embodiment includes a shank portion 61 that is inserted into the tool holding hole 122 of the shrink-fit tool holder 10, and a blade portion 60 b that extends from the shank portion 61 toward the distal end side in the axial direction. The shank portion 61 is formed on the outer periphery of the rear end portion of the shank portion 61 and is in contact with the pressing surface 231 of the side lock bolt 23. The shank portion 61 is formed on the front end side of the flat surface 62 and is a shrink-fit type tool attachment / detachment. And a cylindrical region 61c having a length equal to or longer than a predetermined effective grasping length L to be fastened to the portion 12. The flat surface 62 is inclined so as to be directed toward the distal end side in the axial direction at a predetermined angle of 1 to 10 degrees with respect to the axis of the shank portion 61. As a result, the shank portion 61 is grasped and centered with a sufficient effective grasping length L by the tool attaching / detaching portion 12 of the shrink-fit tool holder 10. Then, the side lock type attaching / detaching portion 21 of the shrink-fit tool holder 10 is securely prevented from coming off and rotating.

  In addition, since the cutting tool 65 of the modified example further includes a liquid passage 66 extending from the shank part 61 to the cutting part 60b, the cutting fluid flows through the cutting tool 65 and is supplied to the cutting portion of the workpiece, thereby improving the cutting performance.

  Next, a second embodiment of the present invention will be described. FIG. 8 is an enlarged longitudinal sectional view showing the tip region of the shrink-fit tool holder 20 according to the second embodiment of the present invention, and shows a state in which a short stopper is used. FIG. 9 is a front view showing the tip portion in the axial direction of the second embodiment. FIG. 10 is an enlarged longitudinal sectional view showing the tip region of the second embodiment, and shows a state in which a long stopper is used. For reference, FIGS. 8 and 10 show a blade inserted into the tool holding hole of the shrink-fit tool holder. About 2nd Embodiment, about the structure which is common in 1st Embodiment mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted, and a different structure is demonstrated below. The shrink-fit tool holder 20 of the second embodiment has two through holes 22 and 22b and two side lock bolts 23 and 23b. As shown in FIG. 9, a marking 24 is disposed at the distal end portion of the tool attaching / detaching portion 12 at a circumferential position corresponding to the through hole 22 as in the first embodiment described above. The marking 24 is provided on both the outer peripheral surface 12g and the front end surface of the tool attaching / detaching portion 12. Further, a marking 24b is provided at a circumferential position corresponding to the through hole 22b.

  The 1st through-hole 22 and the 2nd through-hole 22b are arrange | positioned at two places away by the predetermined angle of 60 to 120 degree | times in the circumferential direction of a holder main body. The first through hole 22 and the second through hole 22b of the second embodiment are separated by 90 degrees in the circumferential direction. Moreover, the 1st through-hole 22 and the 2nd through-hole 22b are the same shape, the same dimension, and the same inclination angle. The second side lock bolt 23b is screwed into the second through hole 22b so that the first side lock bolt 23 is screwed into the first through hole 22.

  FIG. 11 is an overall view showing the cutter 70 chucked in the second embodiment. The blade 70 also has a first flat surface 62 and a second flat surface 63 that are formed at two locations separated by a predetermined angle of 60 degrees or more and 120 degrees or less in the circumferential direction of the shank portion 61. Specifically, the first flat surface 62 and the second flat surface 63 are separated by 90 degrees in the circumferential direction. 90 degrees here is an angle from the circumferential center of the first flat surface 62 to the circumferential center of the second flat surface 63.

  The inclination angle of the second flat surface 63 with respect to the axis of the shank portion 61 is the same as that of the first flat surface 62. The shape and dimensions of the second flat surface 63 are also the same as those of the first flat surface 62. The first flat surface 62 is in contact with the pressing surface 231 of the first side lock bolt 23, and the second flat surface 63 is in contact with the pressing surface 231 of the second side lock bolt 23b. At this time, as indicated by an arrow in FIG. 12, the pressing surface 231 at the tip of the first side lock bolt 23 presses the flat surface 62, and the rear end of the shank portion 61 is pressed from the first side lock bolt 23 in the inner diameter direction. Receive. At the same time, the inner peripheral surface of the small-diameter portion 122 s comes into surface contact with the outer peripheral surface of the rear end portion of the shank portion 61 to receive the pressing force from the first side lock bolt 23. Specifically, as indicated by arrows in FIG. 12, the inner peripheral surface of the small diameter portion 122 s is the reaction force in the inner diameter direction on the outer peripheral surface of the rear end portion of the shank portion 61 at a position 180 degrees away from the through hole 22 in the circumferential direction. Is granted. Further, the pressing surface 231 at the tip of the second side lock bolt 23b presses the flat surface 63 in the inner diameter direction, and the inner peripheral surface of the small diameter portion 122s is behind the shank portion 61 at a position 180 degrees away from the through hole 22b in the circumferential direction. A reaction force in the inner diameter direction is applied to the outer peripheral surface of the end. Thus, the axis of the shank portion 61 is held so as not to deviate from the axis O of the tool holder body.

  By the way, the shrink-fit type tool holder 20 of 2nd Embodiment is the side lock type attaching / detaching part 21, and the side lock type attaching / detaching part 21 is separated in the circumferential direction of the holder main body 11 at a predetermined angle of 60 degrees or more and 120 degrees or less. The first and second through holes 22 and 22b are formed, the first side lock bolt 23 is screwed into the first through hole 22, and the second side lock bolt 23b is screwed into the second through hole 22b. As a result, the pressing force applied to the shank portion 61 by the first side lock bolt 23 and the pressing force applied to the shank portion 61 by the second side lock bolt 23b intersect each other, and the shank portion 61 is connected to the inner peripheral surface of the tool attaching / detaching portion 12. The centering accuracy of the blade 70 is maintained by suitably pressing to 12h. Further, since the two side lock bolts 23 and 23b are used, the pull-out function and the anti-rotation function are improved as compared with the case of one.

  Further, the blade 70 of the second embodiment has first and second flat surfaces 62 and 63 formed at two positions separated by a predetermined angle of 60 degrees or more and 120 degrees or less in the circumferential direction of the shank portion 61, and The first flat surface 62 contacts the pressing surface 231 of the first side lock bolt 23 of the second embodiment, and the second flat surface 63 contacts the pressing surface 231 of the second side lock bolt 23b of the second embodiment. . As a result, the pressing force applied to the first flat surface 62 and the pressing force applied to the second flat surface 63 intersect each other, and the shank portion 61 is suitably pressed against the inner peripheral surface 12h of the tool attaching / detaching portion 12, thereby cutting the tool. A centering accuracy of 70 is maintained. Further, since the two inclined flat surfaces are provided, the function of pulling out and preventing the shank 61 is improved.

  Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

The shrink-fit tool holder according to the present invention does not apply a radial pressing force in a specific direction to the shank portion of the blade. In the blade according to the present invention, the shank portion of the blade does not receive a specific radial pressing force. This provides improved chucking.

10 shrink-fit tool holder, 11 holder body,
12 Tool attachment / detachment part, 12g outer peripheral surface,
12h inner peripheral surface, 122 tool holding hole,
122b Large diameter part of the tool holding hole, 122s Small diameter part of the tool holding hole,
123 intermediate hole, 124 annular step, 13 mounting part,
132 Pull stud mounting hole, 133 connecting hole, 133t female thread
14 flange, 142 V-groove,
21 side lock type attaching / detaching part, 22 (first) through hole,
22b 2nd through hole, 23 1st side lock bolt,
23b Second side lock bolt, 231 holding surface,
233 bolt body, 234 holding member, 24, 24b marking,
25, 26 stopper, 251 tip surface, 253 communication passage,
27 Preloading bolts, 271 holding surface,
273 communication passage, 60 blade, 60b blade
61 Shank part, 61c Cylindrical area, 62 (1st) flat surface
63 second flat surface, 64 rear end surface, 65 blade,
66 liquid passage, 70 blade, L effective grasp length, O axis.

Claims (12)

A round hole extending from the front end in the axial direction toward the rear end side in the axial direction, a tool holding hole for shrink-fitting a shank portion of the blade, a hole having a larger diameter than the tool holding hole, A large-diameter portion that extends further from the bottom of the hole toward the rear end side in the axial direction and passes through a rear end portion of the shank portion of the cutter inserted into the tool holding hole, and a hole having a smaller diameter than the large-diameter portion. A holder main body having a small-diameter portion extending from the diameter portion toward the rear end side in the axial direction and receiving the rear end portion of the shank portion of the cutter,
With respect to a cylindrical region having an outer peripheral surface having a constant radius on the front end side of the shank portion of the shank portion of the cutter that is provided in the front end region in the axial direction of the holder body and is inserted into the tool holding hole, A cylindrical shrink-fit detachable portion that grasps and centers by shrink fitting over a predetermined effective grasp length so that the axis of the cutter matches the axis of the holder body;
One or more side lock bolts that are provided at one or more locations on the rear end side in the axial direction with respect to the shrink-fitting detachable portion and extend from the outer peripheral surface of the holder body to the tool holding hole, and screwed into the through hole The through hole extends at an angle of 1 to 10 degrees with respect to the direction perpendicular to the axis so that the outer diameter side is closer to the tip side in the axial direction than the inner diameter side, and the side lock bolt is A flat pressing surface provided at the tip of the side lock bolt by being screwed into the tool holding hole in a state where the cylindrical region of the shank portion of the cutter is grasped and centered by the shrink-fitting detachable portion. with pressing the inclined is brought into contact with the flat surface the flat surface is provided on the outer periphery of the rear end portion of the shank portion of the blade and the inner circumferential surface of the small diameter portion relative to the pressing pressure of the blade sheet Comprising a side-locking detachable unit that applies reaction force to the outer peripheral surface of the rear end portion of the link portion,
A shrink-fit tool holder configured to chuck the shank portion of the cutter by the shrink-fit detachable portion and the side lock detachable portion.   The shrink-fit tool holder according to claim 1, wherein a marking is provided at a circumferential position corresponding to the through hole at an axial end portion of the holder body. The through hole of the side lock type attaching / detaching portion includes first and second through holes provided at two positions separated by a predetermined angle of 60 degrees or more and 120 degrees or less in the circumferential direction of the holder body,
The shrink-fit type according to claim 1, wherein the side lock bolt includes a first side lock bolt that is screwed into the first through hole and a second side lock bolt that is screwed into the second through hole. Tool holder. The side lock bolt includes a bolt main body screwed into the through hole,
The shrink-fit type tool according to any one of claims 1 to 3, further comprising a pressing member formed with the pressing surface and attached to a tip portion of the bolt body so that the direction of the pressing surface can be changed. holder.   The shrink-fit type according to any one of claims 1 to 4, further comprising a stopper provided on a hole bottom side of the tool holding hole and defining an axial position of a shank portion of the cutter inserted into the tool holding hole. Tool holder.   The tool holder according to claim 5, wherein the stopper is a member accommodated on the bottom side of the tool holding hole, and is replaceable with either a long stopper or a short stopper. The stopper is a member accommodated on the bottom side of the tool holding hole,
An internal thread extending from the bottom of the tool holding hole to the rear end side in the axial direction of the bolt body, and a preload bolt that is screwed into the internal thread and applies a pressing force in the front end direction to the shank portion of the blade through the stopper The tool holder according to claim 5 or 6, further comprising:   A female screw extending from the bottom of the tool holding hole to the rear end side in the axial direction of the bolt main body, and a preloading bolt that is screwed into the female screw and applies a pressing force in the front end direction to the shank portion of the blade. The shrink-fit tool holder according to any one of claims 1 to 4. The stopper and the preload bolt have a connecting passage that penetrates in the axial direction,
Wherein the communicating passage is shrink-fit tool holder according constituted, in claim 7 or 8 so as to connect the rear end opening of the liquid passage provided in the shank portion of the blade. A shrink-fit tool holder according to any one of claims 1 to 9, and a shank portion of a cutter to be inserted into the tool holding hole,
The shank part is formed at one or more locations on the outer periphery of the rear end part of the shank part, and is formed on the front side of the flat surface so as to come into contact with the pressing surface of the side lock bolt. A cylindrical region having a length equal to or longer than a predetermined effective grasping length to be tightened to the part,
The blade chucking structure in which the flat surface is inclined so as to be directed toward the front end side in the axial direction at a predetermined angle of 1 to 10 degrees with respect to the axis of the shank portion. The flat surface includes first and second flat surfaces formed at two locations separated by a predetermined angle of 60 degrees or more and 120 degrees or less in the circumferential direction of the shank portion,
The first flat surface is in contact with a pressing surface of the first side lock bolt among the side lock bolts,
The cutter chucking structure according to claim 10, wherein the second flat surface is in contact with a pressing surface of the second side lock bolt among the side lock bolts. The blade chucking structure according to claim 10 or 11, further comprising a liquid passage extending from the shank portion to the blade portion of the blade.

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