JP6676599B2 - Tool holder - Google Patents

Description

  The present invention relates to a tool holder for chucking a cutting tool, and more particularly to a technique for correcting the inclination of the cutting tool.

  In order to realize high-precision cutting in machine tool processing, it is necessary to maintain the mounting accuracy of the cutting tool with high accuracy. In general, the accuracy of chucking a cutting tool with a tool holder is based on the runout accuracy of the tip that is a predetermined distance away from the chuck portion of the cutting tool in the direction of the cutting edge. Is 3 to 5 [μm]. That is, even if a tool such as a burnishing reamer or a drill is chucked with a high-precision tool holder, it is difficult to make the run-out of the cutting edge of the tool as close to zero as possible. Therefore, conventionally, as described in Japanese Patent No. 3704320 (Patent Literature 1) and Japanese Patent No. 4092221 (Patent Literature 2), a tool holder that can correct the run-out of the cutting edge of a tool is known.

  In the tool holder described in the patent document, a ring member is rotatably attached to the outer periphery of the holder main body. This ring member incorporates an eccentric cam for correcting blade tip runout. This eccentric cam is arranged at only one location in the circumferential direction of the tool holder. The eccentric cam is interposed between the roller holding cylinder at the front end of the tool holder and the holder main body at the rear end, and can press the roller holding cylinder toward the front end. The roller holding cylinder is slightly inclined with respect to the axis of the holder main body by being pressed at one location in the circumferential direction by the eccentric cam. As a result, the blade tool chucked to the roller holding cylinder also slightly inclines, and the blade edge (tip of the blade tool) is corrected.

  The tool holder described in the patent document is mounted on a main shaft of a machining center and rotates together with the main shaft. That is, the cutting tool or tool chucked by the tool holder described in the patent document is a rotary tool for a machining center. For example, when finishing a workpiece with a rotary tool such as a reamer, it is sufficient to adjust the run-out of the cutting edge of the rotary tool to “0”. If the run-out of the cutting edge is set to "0", the run-out of the cutting edge at the entrance of the prepared hole of the work becomes "0", and a finished hole is cut and formed in the work along the prepared hole.

Japanese Patent No. 3704320 Japanese Patent No. 4092221

  The inventor has noticed a problem that a workpiece cannot be machined with high accuracy even if a rotary holder described in Patent Document is interposed between a turret and a tool of a lathe. For this reason, in the tool holder described in the patent document, the roller holding cylinder can be slightly inclined with respect to the axis of the holder main body, but the center of the roller holding cylinder is aligned with the axis of the holder main body. I realized that I couldn't match.

  This is because, when machining a workpiece on a lathe, the tool mounted on the turret of the lathe is not the above-mentioned rotating tool but a stationary tool that does not rotate. For this reason, it turned out that it was not enough to correct only the inclination of the cutting edge in a lathe.

  The present invention has been made in view of the above circumstances, and has as its object to provide a tool holder capable of processing a work with higher accuracy than in the past for a stationary tool for a lathe.

For this purpose, a tool holder according to the present invention is a tool holder attached to a turret of a lathe, and is formed at a holder shank portion provided at a rear end portion, a cylindrical portion provided at a distal end portion, and a distal end portion of a cylindrical portion. A shank member having a large-diameter end portion extending in the outer diameter direction, and a central round hole extending from the large-diameter end portion to the rear end side; a fitting portion provided at the rear end portion to fit into the central round hole; A tip member provided with a tool gripping means for chucking a shank portion of a tool, and an outer diameter end provided at a different circumferential position of the tip large diameter portion and connected to an outer peripheral surface of the tip large diameter portion. A plurality of female screw holes whose inner diameter ends are connected to the central round hole; centering means screwed into each of the female screw holes to align the center of the tip member with the center line of the lathe spindle; And it is provided on one and a tilt adjusting means for adjusting the attitude of the distal end member.
The inclination adjusting means includes: a ring member rotatably attached to the outer periphery of the cylindrical portion of the shank member; a stopper member attached to the outer periphery of the rear end portion of the cylindrical portion to fix the ring member; One or a plurality of cam mechanisms are disposed at the directional position, and the cam mechanism adjusts the posture of the tip member by pushing a predetermined portion in the circumferential direction of the large-diameter portion of the tip of the shank member toward the tip side.
The tool grasping means includes a tip center hole extending from the tip end of the tip member to the rear end side, a female screw portion formed on the inner periphery of the tip center hole, and extending from the bottom of the tip center hole toward the rear end side. A taper hole, a taper collet having a tool insertion hole formed on the inner periphery and a tapered surface formed on the outer periphery and inserted into the tapered hole, and an engaged portion for engaging with a spanner and formed on the outer periphery An annular lock member having a male screw portion, the male screw portion being screwed into the female screw portion within the center hole at the distal end, and pressing the taper collet into the taper hole to reduce the diameter of the tool insertion hole; Surface treatment is performed between the annular flat pressing surface directed to the end side and the annular flat receiving surface provided at the tip of the tapered collet and directed to the tip side so that both end surfaces have low friction. Ring plain plain Including the grayed.

According to the present invention, in a tool gripper provided with a roller holding cylinder, or a taper collet type tool gripper, or a tool holder provided with another type of tool gripper, a tilt for adjusting the attitude of the tool gripper is provided. The apparatus further includes adjusting means and centering means for aligning the center of the tip member with the center line of the lathe spindle. The posture and center of the tip member having the tool grasping means are adjusted by these two kinds of means. ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to adjust the inclination of a cutting tool and the center of a cutting tool to a desired state, and the processing accuracy improves in a stationary tool.
Further, according to the present invention, the cam mechanism can be set at a desired circumferential position by rotating the ring member. Therefore, the inclination can be easily adjusted.
Further, according to the present invention, the posture of the blade can be easily adjusted by one cam mechanism. Alternatively, the posture of the blade can be suitably adjusted by a plurality of cam mechanisms. The plurality of cam mechanisms are provided on the above-described ring member, and the ring member is rotatable. As another example, the ring member is non-rotatably fixed to the cylindrical portion.
Further, according to the present invention, the lock member for pushing the collet chuck into the tapered hole enters into the center hole at the front end of the collet chuck body. Therefore, the projection distance from the tip of the tool holder to the tip of the tool chucked by the tool holder is shorter than before, contributing to the improvement of machining accuracy.
According to the invention, when the lock member is tightened, the tapered collet is pushed along the axis of the tapered hole by the plain bearing whose surface is treated so as to have low friction. Therefore, the center of the tool can be aligned with the axis of the tool holder.

  The tool holder of the present invention is at least partially made of steel. As a preferred aspect of the present invention, the fitting portion of the tip member is made of steel, and the outer peripheral surface is hardened by a quenching process. According to this aspect, since the pushing hardness of the outer peripheral surface of the fitting portion is increased, even if the adjustment bolt is repeatedly tightened or loosened to repeatedly abut on the outer peripheral surface of the fitting portion, the fitting bolt of the fitting portion is removed. The coefficient of friction of the outer peripheral surface can be kept low. Therefore, the operator can easily center the center of the tip member on the axis of the shank member.

  With respect to the center line of the lathe spindle, the position of the centering means in the center line direction is not particularly limited. As a preferred aspect of the present invention, the centering means is disposed on the rear end side of the gauge line of the tool grasping means.

  The number and layout of the female screw holes of the centering means are not particularly limited, but as a preferred aspect of the present invention, the plurality of female screw holes of the centering means are arranged at equal intervals in the circumferential direction of the large diameter portion at the tip. According to this aspect, it is possible to suitably adjust the cutting edge of the stationary tool (blade). More preferably, the female screw holes are preferably arranged at intervals of 90 ° in the circumferential direction.

  The shape of the lock member is not particularly limited, but as one aspect of the present invention, the outer diameter of the lock member is equal to the inner diameter of the front center hole. According to this aspect, the lock member can be housed in the center hole at the distal end, and the tool holder can be shortened.

  The location where the pressing surface and the plain bearing are arranged is not particularly limited, but as a preferred aspect of the present invention, the lock member center hole of the lock member is formed such that the inner diameter of the central portion in the axial direction is smaller than the inner diameter of the rear end portion. A pressing surface is provided on an annular step formed by a difference in inner diameter of the lock member, and the plain bearing is housed in a rear end portion of the lock member center hole, and is provided on an inner periphery of the rear end portion of the lock member center hole to pass through the plain bearing. The device further includes a retaining means for stopping. According to this aspect, when the lock member is separated from the collet chuck main body, the plain bearing is prevented from being accidentally dropped.

  The lock member only needs to push the taper collet toward the rear end in the axial direction, but as a preferable aspect of the present invention, the taper collet has an annular nose portion projecting from the annular portion on the inner diameter side to the distal end side from the receiving surface, And a flange protruding outward from the tip of the nose. The locking member surrounds the root of the nose with the locking member center hole, and is locked between the receiving surface of the tapered collet and the flange. According to this aspect, since the taper collet is engaged with the lock member, when the lock member is rotated in the loosening direction, the taper collet is pulled out from the tapered hole, so that the operation of separating the tool from the tool holder is performed efficiently. be able to.

  Although the shape of the lock member is not particularly limited, as one aspect of the present invention, the lock member center hole is formed such that the inner diameter of the central portion in the axial direction is smaller than the inner diameter of the distal end portion. The flange of the taper collet is housed at the tip of the lock member center hole. According to this aspect, the tip end of the taper collet is housed in the central hole of the lock member, so that the tool holder can be prevented from being lengthened.

  Since the lock member is rotated in the tightening direction or the loosening direction, it has an engaged portion for engaging with a wrench or the like. The shape of the engaged portion is not particularly limited, but as a preferable aspect of the present invention, the lock member center hole is formed such that the inner diameter of the front end portion is smaller than the inner diameter of the rear end portion, and the engaged portion of the lock member is locked. A plurality of round holes with a bottom provided at intervals in the circumferential direction of the member and directed to the distal end side, and the round holes are located on the outer diameter side of the distal end portion of the lock member center hole and higher than the male screw portion of the lock member. It is arranged on the inner diameter side. According to this aspect, the engaged portion does not protrude from the lock member to the distal end side, which contributes to downsizing of the lock member.

  The plain bearing reduces the friction between the locking member and the tapered collet, smoothes the rotation of the locking member, and causes the tapered collet to follow the tapered hole of the collet chuck body. As a preferred aspect of the present invention, the surface treatment of the plain bearing is a coating treatment or a polishing treatment. The coating means forming a low friction layer on the surface of the plain bearing. Polishing refers to forming the surface of the plain bearing itself smoothly.

  The collet chuck body is mounted on the machine tool at the holder shank at the rear end. The shape of the holder shank is not particularly limited. For example, the holder shank portion is a straight shank having a predetermined outer diameter and extending in the axial direction.

  As described above, according to the present invention, the position and orientation of the blade in the direction perpendicular to the axis can be adjusted by the two kinds of adjusting means. Therefore, the inclination of the cutting edge can be corrected with higher accuracy than before.

1 is an overall view showing a tool holder according to an embodiment of the present invention. It is a front view showing the embodiment. It is a longitudinal cross-sectional view which expands and shows the front-end | tip part of the embodiment. It is a figure which disassembles and shows the embodiment into the main components. It is a front view which takes out and shows the lock member of the embodiment. It is a front view showing the plain bearing of the embodiment. FIG. 3 is an exploded view showing the plain bearing and the lock member of the embodiment. It is an exploded perspective view showing a cam mechanism. It is sectional drawing which shows a cam mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall view showing a tool holder according to an embodiment of the present invention. The left side of FIG. 1 is a side view, and the right side of FIG. 1 is a longitudinal sectional view. FIG. 2 is a front view showing the tool holder of the embodiment. FIG. 3 is an enlarged longitudinal sectional view showing a tip end portion of the tool holder according to the embodiment. In order to facilitate understanding of the present invention, FIG. 3 exaggerates the posture of the tip member and the position in the direction perpendicular to the axis, which are corrected by the centering mechanism and the tilt adjusting mechanism described later. FIG. 4 is an exploded view showing the tool holder of the embodiment into main components, including a side view of the taper collet.

  The tool holder 10 includes a shank member 12 and a tip member 31 as main components. The tip member 31 has tool grasping means for chucking the shank portion 101 of the tool 100. The tool 100 includes, for example, a cutting tool such as an end mill or a drill used for cutting. In the following description, with respect to the axis O of the shank member 12, the side on which the tool 100 is chucked (the lower side in the drawing of FIG. 1) is referred to as the front end side in the direction of the axis O (hereinafter, simply referred to as the front end side). 1 (upper side in FIG. 1) is the rear end side in the direction of the axis O (hereinafter, simply referred to as the rear end side).

  The shank member 12 and the tip member 31 are connected in series in the direction of the axis O. In principle, the axis of the tip member 31 coincides with the axis O of the shank member 12. However, the center and the posture of the tip member 31 are adjusted with respect to the axis O of the shank member 12 by the centering means and the inclination adjusting means described later.

  As shown in FIG. 1, the shank member 12 occupies a central region from the rear end of the tool holder 10 in the direction of the axis O. The tip member 31 occupies the tip region of the tool holder 10. As will be described in detail later, the shank member 12 and the tip member 31 form a center hole extending along the axis O so as to penetrate from the front end to the rear end of the tool holder 10.

  The shank member 12 includes a holder shank portion 13 formed in a rear end region in the direction of the axis O, a cylindrical portion 14 formed in a front end region, and a large end portion 15 formed in a front end portion. The holder shank portion 13 is a straight shank that extends from the rear end of the tool holder 10 to the center with a constant outer diameter. A flat surface 13p is formed at one location in the circumferential direction of the holder shank portion 13 and extends elongated parallel to the axis O. The holder shank portion 13 is mounted on a machine tool (not shown), for example, a plurality of tool rests provided on a rotatable turret head.

  The tip of the holder shank 13 is connected to the rear end of the cylindrical portion 14. The cylindrical portion 14 has a bottomed cylindrical shape that opens to the distal end side. The outer diameter of the cylindrical portion 14 is larger than the outer diameter of the holder shank portion 13.

  At the tip of the cylindrical portion 14, a flange-shaped tip large-diameter portion 15 spreading toward the outer diameter side is formed. A circumferential groove 28 is formed at the boundary between the cylindrical portion 14 and the large-diameter portion 15 at the tip. The circumferential groove 28 extends along the outer circumference of the cylindrical portion 14. For this reason, the connecting portion between the cylindrical portion 14 and the large-diameter portion 15 at the tip is made thin, and a slight elastic deformation becomes possible. This is for the inclination adjusting means described later.

  A center round hole 16 extending toward the rear end is formed on the front end surface of the large-diameter end portion 15 which is also the front end surface of the shank member 12. The center round hole 16 has a constant inner diameter about the axis O, and forms the inner peripheral surface of the large-diameter portion 15 and the cylindrical portion 14. The distal end member 31 is fitted into the center round hole 16 from the distal end side. A through hole 17 is further formed at the bottom of the center round hole 16. The through hole 17 extends through the holder shank portion 13 and extends to the rear end of the shank member 12.

  The region from the rear end of the distal end member 31 to the center portion forms a fitting portion 33. The fitting portion 33 is inserted into the center round hole 16 of the shank member 12 and fits with the shank member 12. The outer diameter of the fitting portion 33 is formed to be constant in the direction of the axis O corresponding to the inner diameter of the central round hole 16. A flange portion 34 extending toward the outer diameter side is formed at the tip of the fitting portion 33. The flange portion 34 of the tip member 31 is not inserted into the center round hole 16 of the shank member 12 and is adjacent to the tip large-diameter portion 15 of the shank member 12. The outer diameter of the large-diameter portion 15 and the outer diameter of the flange 34 are the same. The large-diameter portion 15 and the flange portion 34 are connected in series in the direction of the axis O by a connecting bolt 66 extending in the direction of the axis O, and constitute an outer peripheral surface of the tool holder 10.

  The large-diameter portion 15 at the distal end of the flange, which spreads to the outer diameter side around the axis O, is slightly elastically deformable. The position of the tip large-diameter portion 15 in the direction of the axis O generally coincides over the entire circumference of the tip large-diameter portion 15, but a part of the tip large-diameter portion 15 in the circumferential direction is higher than other portions by the tilt adjusting means described later. Can also be displaced slightly toward the distal end. Then, the flange portion 34 of the distal end member 31 that contacts the distal end surface of the distal end large diameter portion 15 is slightly inclined with respect to the axis O, and the attitude of the distal end member 31 changes with the tool 100.

  Here, the connection structure between the shank member 12 and the tip member 31 will be described.

  As shown in FIG. 2, a plurality of concave portions 37 are formed in the flange portion 34 of the distal end member 31 at intervals in the circumferential direction. Each of the recesses 37 is formed in a stepped portion which is cut out from the outer peripheral surface of the flange portion 34 toward the inner diameter side and which recedes from the distal end surface of the flange portion 34. In the present embodiment, the concave portions 37 are provided at four locations so as to be at equal intervals in the circumferential direction 90 °. As shown in FIG. 1, a through hole 38 is provided on the bottom surface of the concave portion 37 that recedes from the distal end surface of the flange portion 34. Each through hole 38 is connected to the rear end face of the flange portion 34.

  A plurality of female screw holes 19 having a bottom are formed in the large-diameter portion 15 at the tip end of the shank member 12 at intervals in the circumferential direction. Each female screw hole 19 extends from the distal end surface of the distal end large-diameter portion 15 to the rear end side, is arranged corresponding to the circumferential position of each through hole 38, and is connected to each through hole 38. A coupling bolt 66 is passed through each through hole 38 from the tip side. The shaft of each coupling bolt 66 is screwed into the female screw hole 19, and the head of each coupling bolt 66 is housed in the concave portion 37 while being locked to the flange 34. The tip member 31 is connected and fixed to the shank member 12 by rotating each coupling bolt 66 in the tightening direction.

  A plurality of coupling bolts 66 are arranged at intervals in the circumferential direction. Specifically, they are arranged at 90 ° intervals. The connecting bolts 66 of the present embodiment are arranged at equal intervals, but as a modified example (not shown), the connecting bolts 66 may be arranged at different intervals.

  Next, the tool grasping means provided on the tip member 31 will be described.

  An annular distal end annular portion 35 protruding toward the distal end side is formed on the distal end surface of the flange portion 34. The inner periphery of the distal annular portion 35 of the distal member 31 defines a distal center hole 36. The tip center hole 36 has a constant inner diameter with respect to the axis O. At the bottom of the front end center hole 36, a tapered hole 32 that extends from the front end side to the rear end side is extended. The inner diameter of the tip center hole 36 is larger than the tapered hole 32. The centers of the tapered hole 32 and the tip center hole 36 coincide with the axis of the tip member 31. A taper collet 41 is inserted into the tapered hole 32 from the center hole 36 at the distal end. A lock member 51 is disposed in the distal end center hole 36. A female screw portion 36n is formed on the inner periphery of the distal end annular portion 35. As will be described in detail later, the female screw portion 36 n is screwed with a male screw portion 52 formed on the outer periphery of the lock member 51. The bottom of the tip center hole 36 substantially coincides with the gauge line of the tool grasping means for chucking the tool 100. The gauge line is the tip of the axial region where the tapered collet 41 is firmly grasped by the tapered hole 32. With the shank member 12 and the tip member 31 assembled, the through hole 17, the central round hole 16, and the tapered hole 32 are connected in series in this order.

  Referring to FIG. 3 showing details of the tool gripping means, the taper collet 41 has a tool insertion hole 49 at the center. The tool insertion hole 49 extends to penetrate from the front end to the rear end of the tapered collet 41. On the outer periphery of the tapered collet 41, a tapered surface 42 whose diameter increases from the rear end toward the front end is formed. A flat annular receiving surface 43 directed toward the distal end is provided on the distal end side of the tapered surface 42.

  The tapered collet 41 further has an annular nose portion 44 and a flange portion 45 at the distal end. The annular nose portion 44 protrudes from the annular portion on the inner diameter side of the receiving surface 43 toward the distal end. The flange 45 protrudes outward from the tip of the nose 44.

  The taper collet 41 further has slits 46 and 47. A plurality of slits 46 and 47 are arranged at intervals in the circumferential direction. Further, the slits 46 and 47 are alternately arranged in the front end region and the rear end region of the tapered collet 41, respectively. The slot 46 extends from the front end of the tapered collet 41 toward the rear end. For this reason, the tip side portion of the tapered surface 42, the nose portion 44, and the flange portion 45 are discontinuous in the circumferential direction. The slot 47 extends from the rear end of the tapered collet 41 toward the front end. For this reason, the rear end side portion of the tapered surface 42 is discontinuous in the circumferential direction. With respect to the axis of the tapered collet 41, the axial positions of the slits 46 and 47 overlap at the center of the tapered collet 41.

  The lock member 51 is an annular member, and a male screw portion 52 is formed on the outer periphery. The flat annular end surface 53 of the lock member 51 is provided with an engaged portion 54 for engaging with a spanner (not shown). FIG. 5 is a front view showing the lock member 51 of the present embodiment. The engaged portion 54 is a bottomed round hole that is arranged at intervals in the circumferential direction. The engaged portions 54 of the present embodiment are provided at four locations at 90 ° intervals, but the number and layout of the engaged portions 54 are not particularly limited. A wrench (not shown) has a plurality of pin-shaped protrusions corresponding to the respective engaged portions 54, and engages with the respective engaged portions 54 to apply torque in the tightening direction and the loosening direction to the lock member 51. This will be described in detail later.

  As shown in FIG. 4, the lock member center hole formed in the center of the lock member 51 has a front end portion 55, a center portion 56, and a rear end portion 57 which are continuous in this order. The inner diameter of the distal portion 55 is larger than the inner diameter of the central portion 56. Therefore, an annular step 58 is formed at the connection point between the tip portion 55 and the central portion 56. The annular step 58 is an annular surface directed toward the distal end. The distal end portion 55 of the lock member center hole is connected to the distal end surface 53 of the lock member 51.

  The length of each engaged portion 54, which is a small hole having a bottom, in the direction of the axis O is smaller than or equal to the length of the tip portion 55 in the direction of the axis O, or extends rearward from the tip portion 55 although not shown. . In the latter case, the position of the hole bottom of the engaged portion 54 in the direction of the axis O overlaps with the central portion 56. In any case, each engaged portion 54 is disposed on the distal end side with respect to the rear end portion 57.

  The inside diameter of the rear end portion 57 of the lock member center hole is larger than the inside diameter of the front end portion 55. For this reason, an annular step is also formed at the connection point between the rear end portion 57 and the central portion 56. The annular step forms an annular flat pressing surface 59 directed to the rear end side. As will be described in detail later, the pressing surface 59 applies a pressing force to the taper collet 41.

  A plain bearing 61 is interposed between the pressing surface 59 of the lock member 51 and the receiving surface 43 of the tapered collet 41. FIG. 6 is a front view showing the plain bearing 61 of the present embodiment. The plain bearing 61 is a circular disk having a constant thickness, and is formed into a circular plate shape by using a quenched and polished steel plate or the like. Both end surfaces of the plain bearing 61, that is, a rear end side end surface and a front end side end surface are subjected to a surface treatment for reducing frictional resistance between the receiving surface 43 and the pressing surface 59. Such surface treatments include, for example, ion nitriding treatment, DLC (Diamond Like Carbon) coating treatment, TiN coating treatment, mirror-like lapping treatment, and polishing treatment. Both end surfaces of the plain bearing 61 may be oil-film lubricated in combination with the above-described processing or separately.

  The pressing surface 59 of the lock member 51 that is in surface contact with the front end surface of the plain bearing 61 may be a low friction flat surface that has been subjected to a surface treatment so as to reduce the friction coefficient, similarly to the both end surfaces of the plain bearing 61. The same applies to the receiving surface 43 which makes surface contact with the rear end surface of the plain bearing 61.

  As shown in FIG. 4, the plate thickness of the plain bearing 61 is smaller than the length of the rear end portion 57 in the axis O direction, and the plain bearing 61 is housed in the rear end portion 57 of the lock member center hole. A slightly projecting protrusion 57p is provided on the inner peripheral surface of the rear end portion 57. The plain bearing 61 is elastically deformable because it can be stored in the rear end portion 57. The plurality of protrusions 57p are arranged, for example, at intervals in the circumferential direction, and engage with the outer edge of the plain bearing 61. The plain bearing 61 is prevented from falling out of the rear end portion 57 of the lock member center hole by the projection 57p, and is held adjacent to the pressing surface 59. Further, as shown in FIG. 7, the plain bearing 61 is separable from the lock member 51 and can be replaced as appropriate. FIG. 7 is an exploded sectional view showing the lock member and the plain bearing.

  Next, the centering means for adjusting the position of the tip member 31 in the direction perpendicular to the axis O will be described.

  As shown in FIG. 3, a female screw hole 18 is formed in the large-diameter portion 15 at the distal end of the shank member 12. The female screw hole 18 extends in the radial direction from the outer peripheral surface of the large-diameter portion 15 to the inner peripheral surface of the round hole 16 and penetrates the large-diameter portion 15. 2, a plurality of female screw holes 18 are formed at intervals in the circumferential direction. In the present embodiment, female screw holes 18 are provided at four locations so as to be equidistant in the circumferential direction 90 °.

  An adjusting bolt 64 is screwed into each female screw hole 18 from the outer diameter side. As shown in FIG. 3, the distal end surface 65 of the adjustment bolt 64 is directed toward the inner diameter side, and comes into contact with the outer peripheral surface of the fitting portion 33 of the distal end member 31. In the present embodiment, the tip member 31 can be moved relative to the shank member 12 in the direction perpendicular to the axis O by appropriately rotating the adjustment bolts 64.

  The outer peripheral surface of the fitting portion 33 is harder than other portions of the tip member 31. Specifically, it is HRC (Rockwell hardness) 55 or more, more preferably HRC60 or more. For example, by quenching the tip member 31 made of steel, the surface portion of the tip member 31 is made harder than the inside. Increasing the indentation hardness of the outer peripheral surface of the fitting portion 33 facilitates alignment with the adjustment bolt 64.

  Here, as shown in FIG. 2, each recess 37 is disposed between two female screw holes 18 adjacent to each other in the circumferential direction. That is, the concave portions 37 and the female screw holes 18 are alternately arranged at intervals in the circumferential direction of the flange portion 34. In the present embodiment, the female screw holes 18 and the concave portions 37 are arranged at equal intervals in the circumferential direction of 45 °.

  The female screw hole 18 as the centering means is disposed on the rear end side of the gauge line of the tool grasping means (the bottom of the center hole 36 at the front end).

  A procedure for adjusting the position of the tip member 31 in the direction perpendicular to the axis O using the centering means will be described.

  In the following description, the center of the tip member 31 is understood to mean the center point of the tip member at an arbitrary position in the axial direction. If the center of the tip member 31 is continuously shown in the axial direction, it is represented by a dashed line in FIG. The center X can be slightly displaced relative to the axis O of the shank member 12 by the screwing positions of the plurality of adjustment bolts 64. For example, the adjustment bolt 64 disposed on the left side of FIG. 3 is rotated in the tightening direction to be displaced so as to approach the axis O, and the adjustment bolt 64 disposed on the right side of FIG. When it is displaced away from O, the flat end surface 65 of the adjustment bolt 64 presses the fitting portion 33 to the right side of the paper surface, and as shown in an exaggerated manner in FIG. The member 12 is displaced to the right side of the paper with respect to the axis O of the member 12. Since the plurality of adjustment bolts 64 are arranged at different circumferential positions as shown in FIG. 2, the operator appropriately loosens or tightens the one or more adjustment bolts 64 so that the distal end member 31 is aligned with the axis O. It is adjusted in the desired direction at right angles. The displacement by the centering means is several [μm] to several tens [μm].

  Next, a tilt adjusting means for adjusting the tilt of the tip member 31 with respect to the axis O will be described.

  As shown in FIG. 3, a ring-shaped stopper member 21 is attached to the outer periphery of the cylindrical portion 14. Specifically, a male screw 14m is formed on the outer periphery of the rear end of the cylindrical portion 14, and a female screw 21n is formed on the inner circumference of the stopper member 21, and the male screw 14m and the female screw 21n are screwed together. The outer diameter of the stopper member 21 is equal to the outer diameter of the large-diameter end portion 15. The stopper member 21 is arranged at an interval on the rear end side of the large-diameter portion 15 at the front end.

  The stopper member 21 is provided with a side lock bolt hole 21s. The side lock bolt hole 21s is a female screw hole extending from the outer peripheral surface to the inner peripheral surface of the stopper member 21. A side lock bolt is screwed into the side lock bolt hole 21s from the outer diameter side of the stopper member 21. The side lock bolt comes into contact with the outer peripheral surface of the cylindrical portion 14, and the stopper member 21 is attached and fixed to the shank member 12.

  A ring member 22 is interposed between the stopper member 21 and the large-diameter portion 15 at the distal end. The ring member 22 surrounds the outer periphery of the cylindrical portion 14. By rotating the stopper member 21 in the tightening direction (the distal end side), the ring member 22 is interposed between the stopper member 21 and the large-diameter portion 15 at the distal end, and cannot be moved in the direction of the axis O. Further, the ring member 22 is rotatable without being pressed by the stopper member 21 and the large-diameter portion 15 at the distal end.

  A cam mechanism 23 is provided on the ring member 22. The cam mechanism 23 is arranged along the outer peripheral surface of the cylindrical portion 14. This embodiment has only one cam mechanism 23.

  By rotating the ring member 22, the circumferential position of the cam mechanism 23 can be changed to an arbitrary position.

  The cam mechanism 23 of the present embodiment has a cylindrical operating member 24 and a spherical ball 25, and is interposed between the stopper member 21 on the rear end side and the large-diameter portion 15 on the distal end side. The cam mechanism 23 is supported by the distal end surface of the stopper member 21 together with the ring member 22 to suppress displacement to the rear end side and apply a pressing force to the distal end side. The cam mechanism 23 pushes the ball 25 against the rear end face of the specific portion in the circumferential direction of the large-diameter portion 15 at the tip as shown in an exaggerated manner on the left side of the paper surface of FIG. Extrude in the O-direction tip The circumferential specific position is a circumferential position on the opposite side of the axis O when viewed from the direction in which the operator wants to incline the tool 100. The ball 25 is a steel ball or the like.

  FIG. 8 is an exploded perspective view showing the cam mechanism 23. FIG. 9 is a sectional view showing the cam mechanism 23. An eccentric cam groove 24c is formed on the outer peripheral surface of the operation member 24. The eccentric cam groove 24c extends in the circumferential direction of the operation member 24. The groove cross section of the eccentric cam groove 24c has an arc shape corresponding to the outer diameter of the ball 25. However, the groove cross section of the eccentric cam groove 24c is not a constant shape over the entire circumference of the operation member 24, but has a different groove depth depending on the circumferential position of the operation member 24. The same applies to the groove width of the eccentric cam groove 24c. Specifically, as shown in FIG. 9, the circle forming the groove bottom of the eccentric cam groove 24 c is eccentric with respect to the outer peripheral circle of the operation member 24.

  The ring member 22 has a round hole 22h penetrating in the radial direction, and small holes 22j and holes 22k extending parallel to the axis. The small hole 22j extends in the radial direction of the round hole 22h, and connects the inner peripheral surface of the round hole 22h and the distal end surface of the ring member 22. The inner diameter of the small hole 22j corresponds to the outer diameter of the ball 25. The hole 22k is a bottomed hole that extends straight from the end surface of the ring member 22 and extends along a tangent to the inner peripheral surface of the round hole 22h.

  With the operation member 24 inserted through the round hole 22h, one end of the small hole 22j faces the eccentric cam groove 24c. The ball 25 is inserted into the small hole 22j. The ball 25 fits into the eccentric cam groove 24c.

  The hole 22k is adjacent to the outer peripheral surface of the operation member 24 at a position away from the eccentric cam groove 24c. A cylindrical rotation suppressing member 26 made of a synthetic resin, hard rubber, or the like is inserted into the hole 22k. Further, a retaining screw 27 is detachably screwed to the open end of the hole 22k. The holding screw 27 is a stopper that closes the hole 22k and prevents the rotation suppressing member 26 from coming off.

  A procedure for adjusting the attitude of the tip member 31 using the tilt adjusting means will be described.

  When the operator inserts a wrench into a wrench engaging hole 24b formed at one end of the operation member 24 and rotates the operation member 24 as shown by an arrow in FIG. Move along the small hole 22j. Then, when the ball 25 is supported at a shallow portion of the eccentric cam groove 24c as shown in FIG. 9, the ball 25 is pushed out by the operation member 24 and protrudes from the small hole 22j. On the contrary, when the ball 25 is supported at a deep portion of the eccentric cam groove 24c, the ball 25 enters the eccentric cam groove 24c and is stored in the small hole 22j.

  One cam mechanism 23 is arranged at any circumferential position and is supported by the ring-shaped stopper member 21. When the operator appropriately loosens or tightens the cam mechanism 23, a predetermined circumferential portion of the large-diameter portion 15 at the distal end is pushed toward the distal end side from the remaining portion in the circumferential direction. Then, the attitude of the large-diameter end portion 15 with respect to the axis O of the shank member slightly changes. Then, the posture of the distal end member 31 attached and fixed to the distal end large diameter portion 15 by the coupling bolt 66 also changes.

  According to the inclination adjusting means of the present embodiment, the posture of the distal end member 31 is adjusted so as to be inclined at a desired angle with respect to the axis O in a desired circumferential direction. For example, a predetermined portion in the circumferential direction of the large-diameter portion 15 on the left side in FIG. 3 is extruded to the front side more than a position different by 180 ° in the circumferential direction on the right side in FIG. Thus, as shown exaggeratedly in FIG. 3, the tip member 31 is inclined rightward on the paper with respect to the axis O of the shank member 12.

  Here, the rotation suppressing member 26 shown in FIG. 9 is in contact with the outer peripheral surface of the operation member 24, and prevents the operation member 24 from rotating when there is no operation by the operator.

  Next, a procedure for chucking a tool such as a blade tool to the tool holder 10 will be described.

  First, the operator rotates the lock member 51 in the loosening direction in advance. When the lock member 51 is loosened so as to protrude from the distal end face 35f of the distal end member 31 toward the distal end side, the diameter of the tool insertion hole 49 of the tapered collet 41 is sufficiently enlarged. Next, the operator inserts the shank portion 101 of the tool 100 into the tool insertion hole 49 from the distal end side of the lock member 51 through the center hole of the lock member and the center hole of the plain bearing 61.

  Next, the operator engages the wrench with the lock member 51 and rotates the lock member 51 in the tightening direction. Then, the lock member 51 gradually retreats in the axial direction, and the pressing surface 59 of the lock member 51 presses the receiving surface 43 of the tapered collet 41 via the plain bearing 61. Then, the taper collet 41 is pushed into the tapered hole 32 of the tip member 31, and the slits 46 and 47 are narrowed, so that the diameter of the tool insertion hole 49 is gradually reduced. Thereby, the shank portion 101 is fastened to the taper collet 41 over the entire circumference, and the tool 100 is chucked to the tool holder 10.

  When the lock member 51 pushes the tapered collet 41, the plain bearing 61 having a small coefficient of friction is interposed therebetween, so that friction between the two is reduced. For this reason, even if the taper collet 41 does not rotate, the lock member 51 easily rotates. Further, relative movement between the taper collet 41 and the lock member 51 in the direction perpendicular to the axis becomes possible. Therefore, even if the lock member 51 is slightly misaligned from the center of the tip member 31 for some reason, the tapered collet 41 is pushed along the tapered hole 32, and the axis of the tapered collet 41 is shifted to the center X of the tip member 31. Matches. Therefore, according to the present embodiment, the tool 100 is chucked so as to coincide with the center X of the tip member 31, and the misalignment of the tool 100 is prevented.

  When the tool 100 is separated (unchucking) from the tool holder 10, a procedure reverse to the procedure described above may be performed.

  By the way, the tool holder 10 of the present embodiment includes a holder shank portion 13 provided at a rear end portion, a cylindrical portion 14 provided at a distal end portion, and a large-diameter distal end portion 15 formed at the distal end portion of the cylindrical portion 14 and extending in an outer radial direction. A shank member 12 having a central round hole 16 extending from the large-diameter portion 15 to the rear end side; a fitting portion 33 provided at the rear end portion to fit into the central round hole 16; Member 31 having tool grasping means for chucking the shank portion 101 of the tool 100 by means of a tool, and outer diameter ends provided at different circumferential positions of the large-diameter portion 15 and connected to the outer peripheral surface of the large-diameter portion 15. And a plurality of female screw holes 18 whose inner ends are connected to the central round hole 16, and an adjusting bolt 64 screwed into each of the female screw holes 18 to come into contact with the fitting portion 33 of the tip member 31. Multiple adjustments The centering means for adjusting the position of the tip member 31 in the direction perpendicular to the axis O by the screwing position of the bolt 64, the stopper member 21 attached and fixed to the outer periphery of the rear end of the cylindrical portion 14, and the outer peripheral surface of the cylindrical portion 14 Tilt adjusting means having a cam mechanism 23 disposed therein, and adjusting a posture of the distal end member 31 by pushing a predetermined position in a circumferential direction of the distal end large diameter portion 15 toward the distal end side by the cam mechanism 23 supported by the stopper member 21; Is provided.

  According to the present embodiment, in the tool holder 10 including the tool gripping means for chucking the tool 100, the inclination adjusting means for adjusting the attitude of the tool gripping means, and the core for adjusting the position of the tool gripping means in the direction perpendicular to the axis O. It further comprises a matching means. The posture and the position in the direction perpendicular to the axis of the tip member having the tool grasping means are adjusted by these two kinds of adjusting means. ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to adjust the inclination of a cutting tool and the position in the direction perpendicular to the axis of a cutting tool to a desired state, and the processing accuracy at the time of cutting with a cutting tool is improved remarkably. By using these two kinds of adjusting means for the purpose of centering, the center X of the tip member 31 can be made to coincide with the axis O of the shank member 12.

  Further, the fitting portion 33 of the present embodiment is made of steel, and the outer peripheral surface is hardened by the quenching process. Since the outer peripheral surface of the fitting portion 33 is made harder than other portions of the distal end member 31, the friction coefficient of the outer peripheral surface can be reduced, and the adjusting bolt 64 is repeatedly tightened or loosened to form the fitting portion. Even if the outer peripheral surface of the fitting portion 33 is repeatedly contacted, the friction coefficient of the outer peripheral surface of the fitting portion 33 can be kept low. Therefore, the operator can easily center the center X on the axis O. The tip member 31 is easily attached to and detached from the center round hole 16 at the tip of the shank member 12. The tip member 31 can be smoothly rotated while being fitted in the center round hole 16 of the shank member 12.

  Further, the inclination adjusting means of the present embodiment further has a ring member 22 surrounding the outer periphery of the cylindrical portion 14, the ring member 22 is interposed between the stopper member 21 and the large-diameter portion 15 at the tip, and the cam mechanism 23 is a ring member. 22. Accordingly, the ring member 22 can be rotated to set the cam mechanism 23 at a desired circumferential position, and the inclination direction of the tip member 31 can be adjusted.

  In addition, the female screw hole 18 which is a component of the centering means of the present embodiment is disposed on the rear end side with respect to the gauge line substantially coincident with the bottom of the front end center hole 36.

  The female screw holes 18 are arranged at equal intervals in the circumferential direction of the large-diameter portion 15 at the distal end. This facilitates adjustment in the direction perpendicular to the axis.

  Further, the cam mechanism 23 which is a component of the inclination adjusting means of the present embodiment is disposed at any circumferential position of the cylindrical portion 14. Thereby, the posture of the tip member 31 can be adjusted in a direction desired by the operator, and the adjustment work becomes easy.

  Note that the cam mechanism 23 is not limited to this embodiment, and may have a structure shown in FIG. 5 of Japanese Patent No. 4092221 as a modified example (not shown). Further, as a modified example (not shown), the inclination adjusting means may have a plurality of cam mechanisms. The plurality of cam mechanisms are arranged at intervals in the circumferential direction, specifically, for example, at equal intervals in the circumferential direction. As an example, cam mechanisms 23 are provided at four locations in the circumferential direction at 90 ° intervals in an annular region between the stopper member 21 and the large-diameter portion 15 at the distal end. According to such a modification, the ring member 22 can be eliminated, and by operating one or two of the plurality of cam mechanisms 23, the posture of the distal end member 31 can be adjusted.

  The tool grasping means of the present embodiment includes a tip center hole 36 extending from the tip end of the tip member 31 to the rear end, a female screw portion 36n formed on the inner periphery of the tip center hole 36, and a hole in the tip center hole 36. A taper hole 32 extending from the bottom toward the rear end, a taper collet 41 having a tool insertion hole 49 formed on the inner periphery and a tapered surface 42 formed on the outer periphery and inserted into the tapered hole 32; The external thread 52 has an engaged portion 54 and an external thread 52 formed on the outer periphery. The external thread 52 is screwed into the female thread 36n in the center hole 36 at the distal end to push the taper collet 41 into the tapered hole 32. An annular lock member 51 for reducing the diameter of the tool insertion hole 49.

  According to this embodiment, since the lock member 51 is disposed in the center hole 36 at the distal end of the distal end member 31, it is compared with a conventional tool holder having a bag-shaped lock nut described in, for example, Japanese Patent No. 3899324. As a result, the projecting distance from the tool holder 10 to the tip of the tool 100 can be reduced, and the inclination correction of the blade can be reduced. The axial dimension of the lock member 51 is sufficiently smaller than the axial dimension of the conventional bag-shaped lock nut. Since the conventional bag-shaped lock nut is an inner diameter screw, whereas the lock member 51 is an outer diameter screw, the axial dimension of the lock member 51 is set to less than half the axial dimension of the conventional bag-shaped lock nut. can do.

  The tool grasping means of the present embodiment includes an annular flat pressing surface 59 provided on the lock member 51 and directed to the rear end side, and an annular flat pressing surface 59 provided on the distal end portion of the tapered collet 41 and directed to the distal end side. The bearing further includes an annular plain bearing 61 interposed between the bearing surface 43 and the lower end surface and subjected to a surface treatment so that both end surfaces have low friction. By including the plain bearing 61 surface-treated so that at least one end face has low friction, the axis of the tool 100 can be made coincident with the center X of the tip member 31, so that the tool 100 can cut the workpiece. Processing accuracy is improved.

  Further, in the present embodiment, since the outer diameter of the lock member 51 is equal to the inner diameter of the center hole of the distal end, the distal end member 31 can accommodate the lock member 51 as shown in FIG. Therefore, the axial length of the lock member 51 completely overlaps the axial length of the distal end member 31, and the projecting distance from the distal end face 35f to the distal end of the tool 100 can be made shorter than before.

  Further, in the present embodiment, in the lock member center hole of the lock member 51, the inner diameter of the central portion 56 in the axial direction is formed to be smaller than the inner diameter of the rear end portion 57. It is provided on an annular step constituted by a difference in inner diameter of the end portion 57. The plain bearing 61 is housed in the rear end portion 57. On the inner periphery of the rear end portion 57 of the lock member center hole, a projection 57p is further provided as retaining means for retaining the plain bearing 61.

  Further, the tapered collet 41 of the present embodiment includes an annular nose portion 44 protruding distally from an annular portion on the inner diameter side of the receiving surface 43 and a flange portion 45 protruding outward from the distal end portion of the nose portion 44. Have more. That is, the tapered collet 41 is narrowed at the base of the nose 44 located between the receiving surface 43 and the flange 45. The lock member 51 is engaged with the constricted portion. Specifically, the lock member 51 is locked between the receiving surface 43 of the tapered collet 41 and the flange 45 by surrounding the root of the nose portion 44 with the lock member center hole. Accordingly, when the tool 100 is separated from the tool holder 10, when the lock member 51 is rotated in the loosening direction, the taper collet 41 advances with the lock member 51, and the diameter of the tool insertion hole 49 can be enlarged.

  Further, in the present embodiment, the inner diameter of the central portion 56 in the axial direction of the lock member center hole is formed to be smaller than the inner diameter of the distal end portion 55, and the flange portion 45 of the taper collet 41 is connected to the distal end portion 55 of the lock member central hole. Therefore, the projecting distance from the tool holder 10 to the tip of the tool 100 can be further reduced.

  In the present embodiment, the inner diameter of the front end portion 55 of the lock member center hole is formed to be smaller than the inner diameter of the rear end portion, and a plurality of engaged portions 54 are provided at intervals in the circumferential direction of the lock member 51. These round holes are bottomed and directed toward the distal end. These circular holes are arranged on the outer diameter side with respect to the distal end portion 55 of the lock member center hole and on the inner diameter side with respect to the male screw portion 52 of the lock member 51. This contributes to downsizing of the lock member 51.

  The surface treatment applied to the plain bearing 61 of the present embodiment is a coating treatment or a polishing treatment.

  Further, the holder shank portion 13 of the shank member 12 of the present embodiment is a straight shank extending in the axial direction with a predetermined outer diameter, and the shank member 12 is provided on a turret head of an NC turret lathe and revolves, Alternatively, it can be mounted on the tool rest of another lathe. Thereby, the tool holder 10 can be used as a stationary tool for a lathe.

  The embodiments of the present invention have been described with reference to the drawings. However, 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 as the present invention or within an equivalent range.

  The tool holder according to the present invention is advantageously used in a machine tool.

10 tool holder, 12 shank member,
13 Holder shank, 13p flat surface, 14 cylindrical part,
14m male screw, 15 tip large diameter part, 16 center round hole,
18 female screw holes, 19 female screw holes, 21 stopper members,
21n female screw, 21s side lock bolt hole,
22 ring member, 22h round hole, 22j small hole,
22k hole, 23 cam mechanism, 24 operating member,
24b wrench engagement hole, 24c eccentric cam groove, 25 ball,
26 rotation suppressing member, 27 retaining screw, 28 circumferential groove,
31 tip member, 32 taper hole, 33 fitting part,
34 flange part, 35 tip annular part, 53 tip face,
36 center hole at the tip, 36n female thread, 37 recess,
41 taper collet, 42 taper surface, 43 receiving surface,
44 Nose part, 45 flange part, 49 tool insertion hole,
51 lock member, 52 male screw part, 54 engaged part,
55 front end part, 56 center part, 57 rear end part,
57p projection, 58 annular step, 59 pressing surface,
61 plain bearing, 64 adjustment bolt,
66 connecting bolt, 100 tool, 101 shank part,
O Axis of shank member, X Center of tip member.

Claims (9)

A tool holder attached to a turret of a lathe,
A holder shank portion provided at the rear end portion, a cylindrical portion provided at the distal end portion, a large-diameter portion formed at the distal end portion of the cylindrical portion and extending in an outer radial direction, and extending from the large-diameter tip portion to the rear end side. A shank member having a central round hole,
A fitting portion provided at a rear end portion and fitted to the center round hole, and a tip member having tool grasping means provided at the tip portion and chucking a shank portion of a tool;
A plurality of female screw holes provided at different circumferential positions of the distal end large diameter portion, the outer diameter end being connected to the outer peripheral surface of the distal end large diameter portion, and the inner diameter end being connected to the center round hole; and Alignment means having adjustment bolts which are screwed into each of them and come into contact with the fitting portion of the tip member, and wherein the center of the tip member coincides with the center line of the main shaft of the lathe according to screwing positions of the plurality of adjustment bolts. When,
And a tilt adjusting means for adjusting the attitude of the distal end member provided on the shank member,
The inclination adjusting means,
A ring member rotatably attached to the outer periphery of the cylindrical portion,
A stopper member attached to the outer periphery of the rear end of the cylindrical portion to fix the ring member,
One or more cam mechanisms arranged at any circumferential position of the ring member,
By pushing a predetermined location in the circumferential direction of the large-diameter portion of the distal end toward the distal end side by the cam mechanism, the posture of the distal end member is adjusted,
The tool grasping means,
A tip center hole extending from the tip end of the tip member to the rear end side,
A female screw portion formed on the inner periphery of the tip center hole,
A tapered hole extending from the bottom of the tip center hole toward the rear end,
A tool insertion hole formed on the inner periphery, and a taper collet having a tapered surface formed on the outer periphery and inserted into the tapered hole,
An engaged portion for engaging with a spanner, and a male screw portion formed on the outer periphery, wherein the male screw portion is screwed into the female screw portion within the center hole at the distal end, and the tapered collet is inserted into the tapered hole. An annular lock member for reducing the diameter of the tool insertion hole by pushing in,
An annular flat pressing surface provided on the lock member and directed to the rear end side,
An annular plain bearing that is interposed between an annular flat receiving surface provided at the distal end portion of the tapered collet and directed toward the distal end side, and both surfaces of which are subjected to surface treatment so as to have low friction , Tool holder.   The tool holder according to claim 1, wherein the fitting portion is made of steel, and an outer peripheral surface is hardened by a quenching process.   The tool holder according to claim 1, wherein the centering unit is disposed at a rear end side of the gauge line of the tool grasping unit.   4. The tool holder according to claim 1, wherein the plurality of female screw holes of the centering unit are arranged at equal intervals in a circumferential direction of the large-diameter portion at the tip. 5. The lock member center hole of the lock member is formed such that the inner diameter of the central portion in the axial direction is smaller than the inner diameter of the rear end portion, and the pressing surface is provided on an annular step formed by the difference between these inner diameters,
The plain bearing is housed in the rear end portion,
The tool holder according to any one of claims 1 to 4 , further comprising a retaining means provided on an inner periphery of the rear end portion of the lock member center hole to retain the plain bearing. The tapered collet further includes an annular nose portion protruding from the annular portion on the inner diameter side to the distal end side than the receiving surface, and a flange portion projecting outward from the distal end portion of the nose portion,
The tool holder according to claim 5 , wherein the lock member surrounds a root portion of the nose portion with the lock member center hole, and is locked between the receiving surface of the tapered collet and the flange portion. . The lock member center hole is formed such that the inner diameter of the central portion in the axial direction is smaller than the inner diameter of the distal end portion,
The tool holder according to claim 6 , wherein the flange portion of the taper collet is housed in the distal end portion of the lock member center hole. The lock member center hole is formed such that the inner diameter of the front end portion is smaller than the inner diameter of the rear end portion,
The engaged portion is a bottomed round hole that is provided in plurality at intervals in the circumferential direction of the lock member and is directed to the distal end side,
8. The tool holder according to claim 7 , wherein the round hole is arranged on an outer diameter side of the lock member center hole with respect to the distal end portion and on an inner diameter side with respect to the male screw portion of the lock member. 9. The surface treatment is a coating process or polishing process, the tool holder according to claim 1.

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