JP5755363B1 - Small diameter tool holding chuck - Google Patents

Abstract

There is provided a chuck for holding a small-diameter tool which is improved as compared with the prior art. A chuck (10) for holding a small-diameter tool includes a chuck body (11), a cylindrical adapter (21) attached to and fixed to the tip of the chuck body, and a taper collet ( 31), a bevel gear (44) accommodated in the chuck body, a male pulling screw (41) inserted into the collet insertion hole from the end side of the adapter and screwed into the taper collet, and a lateral hole (18) of the chuck body A pinion (61) that is rotatably accommodated and meshes with the bevel gear and rotates the pull screw to reduce the diameter while pulling the taper collet into the collet insertion hole, and an end portion (74) screwed into the adjustment screw hole (19). And a meshing adjustment screw (71) for adjusting the axial position of the pinion in contact with the center of the pinion. [Selection] Figure 1

Description

  The present invention relates to a tool holder in which a distal end portion is attached to a spindle of a machine tool and a tip end portion grasps a shank portion of a small diameter tool.

  Since the small-diameter tool has a small-diameter cutter, it is useful for cutting a relatively small workpiece. As a chuck for holding a small-diameter tool for grasping a small-diameter tool, for example, a chuck described in Japanese Utility Model Publication No. 2-30166 (Patent Document 1) is conventionally known. The small-diameter tool holding chuck described in Patent Literature 1 includes a large-diameter head and a small-diameter bolt portion under the neck, and includes a pull screw extending along the axis of the small-diameter tool holding chuck and a head of the pull screw. A bevel gear and a pinion that meshes with the bevel gear in a posture orthogonal to the axis of the bevel gear. The pinion is secured to the main body of the small diameter tool holding chuck by a retaining ring or a thrust bearing.

No. 2-30166

  However, the conventional small-diameter tool holding chuck has a means for preventing the pinion from coming off, but does not have a means for adjusting the axial position of the pinion. For this reason, it has been difficult to accurately adjust the meshing between the bevel gear and the pinion.

  Further, since the thrust bearing for centering by pressing the bevel gear from the end side is provided, the head portion of the bevel gear can be centered, but the entire pull screw including the bolt portion under the neck has not been centered. In addition, the pinion was not properly centered.

  Further, in order to satisfy the speed-up and high-precision machining of machine tools that have recently been requested, it is conceivable to provide a cutting fluid passage in a small diameter tool holding chuck. However, in the chuck for holding a small-diameter tool of Patent Document 1, if a cutting fluid passage extending linearly from a pull stud bolt hole extending along the axis and passing through the chuck body and the bevel gear is provided, It is difficult to ensure the sealing performance of the joint of the cutting fluid passage of the bevel gear, and the cutting fluid is likely to leak from the joint.

  In view of the above circumstances, an object of the present invention is to provide a chuck for holding a small-diameter tool that has been improved over the prior art.

  For this purpose, a chuck for holding a small-diameter tool according to the present invention has a chuck body having a shank portion provided in a terminal region and a collet insertion hole having an enlarged tip shape extending from the tip toward the tip. A cylindrical adapter to be mounted and fixed, a tool holding hole extending from the distal end toward the distal end, a tapered collet having a female screw hole extending from the distal end toward the distal end and inserted into the collet insertion hole, and accommodated in the internal space of the chuck body Bevel gear and a pull screw having a male thread portion extending from the bevel gear to the tip end side and inserted into the collet insertion hole from the distal end side of the adapter and screwed into the female screw hole of the taper collet, from the outer peripheral surface of the chuck body to the internal space Tapered collet that is rotatably accommodated in the extending lateral hole and meshes with the bevel gear to rotate the pull screw A pinion that is reduced in diameter while being drawn into the collet insertion hole, and is screwed into an adjustment screw hole that extends from the outer peripheral surface of the chuck body to the internal space and is arranged coaxially with the lateral hole across the internal space, and the end is the center of the pinion And a meshing adjustment screw for adjusting the axial position of the pinion.

  According to the present invention, the adjustment screw hole extending from the outer peripheral surface of the chuck body to the internal space is arranged coaxially with the lateral hole that accommodates the pinion, and the meshing adjustment screw that is screwed into the adjustment screw hole is the center of the pinion. Since it abuts on the portion, the axial position of the pinion can be adjusted. Therefore, the meshing between the pinion and the bevel gear can be adjusted appropriately.

  The shape of the end of the engagement adjusting screw that contacts the center of the pinion is not particularly limited. As an embodiment of the present invention, the end of the engagement adjusting screw has a conical shape, and a conical recess for receiving the end of the engagement adjusting screw is formed at the center of the pinion. According to this embodiment, since the tip of the conical adjustment screw is sharp, even if the pinion shaft center is slightly misaligned from a predetermined position, the tip of the engagement adjustment screw is not in the conical recess of the pinion. It can always contact the bottom. Further, the engagement adjustment screw and the pinion can be spotted to reduce the friction. As another embodiment, a conical protrusion may be provided at the center of the pinion, and a conical recess for receiving the conical protrusion of the pinion may be formed at the end of the engagement adjusting screw. Alternatively, as another embodiment, the end portion of the meshing adjustment screw and the center portion of the pinion may be flat surfaces.

  The tip of the adjustment screw sharpened in a conical shape contacts the deep bottom of the conical recess of the pinion, thereby centering the pinion. As a preferred embodiment, the pinion may have an outer peripheral surface in contact with the inner peripheral surface of the horizontal hole and may be centered by the inner peripheral surface of the horizontal hole. According to this embodiment, since the center of the pinion is centered so as to match the predetermined position, the meshing of the bevel gear and the pinion is improved.

  As a preferred embodiment of the present invention, the adapter is preferably arranged coaxially with the chuck body by fitting the distal end of the adapter to the inner peripheral surface of a circular recess formed at the tip of the chuck body, and the pull screw is a cylinder. It further has an outer peripheral surface in contact with the inner peripheral surface of the end portion of the adapter that is shaped, and is centered by the inner peripheral surface of the end portion of the adapter. According to such an embodiment, the adapter is centered so that the axis of the adapter matches a predetermined position. Further, since the center of the bevel gear provided on the pull screw is centered so as to coincide with a predetermined position, the meshing between the bevel gear and the pinion is improved. In addition, since the axial position of the circular recess at the tip of the chuck body that centers the adapter and the axial position of the adapter end that centers the pull screw approach or overlap, it is more centering than when the axial position is far away. Accuracy is improved.

  As a preferred embodiment of the present invention, the small diameter tool holding chuck is provided with a cutting fluid passage. More preferably, it is a passage through which the cutting fluid flows, and is formed in the chuck body passage formed in the chuck body and the cylindrical thick part of the adapter, and one end is connected to the chuck body passage and the other end is connected to the collet insertion hole. And an adapter passage. According to this embodiment, the passage through which the cutting fluid flows can be provided in the small diameter tool holding chuck, bypassing the bevel gear. Therefore, the chuck body passage and the adapter passage can be easily connected without a gap, and the sealing performance of the cutting fluid passage can be ensured. Therefore, a sufficient cutting fluid can be supplied to the tip side of the chuck for holding the small diameter tool, and the high speed and high precision machining of the machine tool which has been requested recently can be satisfied.

  One end of the adapter passage may be disposed on the distal end side of the adapter, and the other end of the adapter passage may be connected to a tip enlarged portion of the collet insertion hole. As a result, the cutting fluid supplied from the main shaft to the chuck main body passage flows through the adapter passage and the slit of the taper collet and is jetted toward the tip of the small-diameter tool. This embodiment is useful for a chuck for holding a small-diameter tool in which the axial length of the adapter is not more than normal.

  An embodiment of the present invention further includes a passage through which a cutting fluid flows, and a tension screw passage formed on the tension screw and having one end extending to the outer peripheral surface of the tension screw and the other end extending to the tip of the tension screw. According to such an embodiment, even for a specification in which the pull screw is formed long and the distance from the chuck body to the taper collet is long, that is, the chuck for holding a small diameter tool whose adapter axial length is longer than usual, it is suitable for a small diameter tool. Cutting fluid can be supplied.

  As a preferred embodiment of the present invention, the pull screw further has an annular flat surface directed to the tip side between the bevel gear and the male screw portion, and the annular flat surface is restricted from axial movement toward the tip side by the end portion of the adapter, A surface-treated portion subjected to a low friction treatment is interposed between the annular flat surface and the end face of the adapter. According to this embodiment, when the pull screw rotates, the friction between the pull screw and the adapter end portion can be reduced. Therefore, the rotational efficiency when the drawing screw rotates while drawing the taper collet is improved, and the operability of the operation of drawing the taper collet and chucking the shank portion of the small diameter tool is improved. The surface treatment portion can be obtained, for example, by subjecting the annular flat surface or the end portion end surface to a low friction treatment. Alternatively, the surface treatment unit may be a washer having both surfaces or one surface subjected to low friction treatment.

  As a preferred embodiment of the present invention, a female screw portion is formed on the outer peripheral surface side of the chuck body among the inner peripheral surface of the lateral hole, and an annular retaining member for retaining the pinion is screwed into the female screw portion, and the chuck The end surface of the pinion directed to the outer peripheral surface side of the main body includes an annular flat surface, and a surface treatment portion subjected to low friction treatment is interposed between the annular flat surface of the pinion and the end surface of the retaining member. According to this embodiment, when the pinion rotates, the friction between the pinion and the retaining member can be reduced. Therefore, the rotation efficiency when tightening and rotating the pinion is improved, and the operability when the pinion is rotated to chuck the shank portion of the small-diameter tool is improved. The surface treatment unit can be obtained, for example, by subjecting the annular flat surface or the end surface to a low friction treatment. Alternatively, the surface treatment unit may be a washer having both surfaces or one surface subjected to low friction treatment.

  As described above, according to the present invention, the meshing of the bevel gear and the pinion can be improved in the assembly manufacturing process of the small diameter tool holding chuck. Further, the user of the small diameter tool holding chuck can appropriately adjust the meshing of the bevel gear and the pinion. By improving the meshing between the bevel gear and the pinion, the operability when chucking a small-diameter tool can be improved.

It is a longitudinal cross-sectional view which shows the small diameter tool holding chuck | zipper which becomes one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the small diameter tool holding chuck | zipper used as the modification of this invention. It is a longitudinal cross-sectional view which shows the small diameter tool holding chuck | zipper used as the further modification of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a small diameter tool holding chuck according to an embodiment of the present invention. The small-diameter tool holding chuck 10 of the present embodiment includes a chuck body 11, an adapter 21, a taper collet 31, a pull screw 41, a pinion 61, and a meshing adjustment screw 71.

  The chuck body 11 is disposed in the end region of the small-diameter tool holding chuck 10, and a tapered shank portion 12 that is tapered toward the end is formed on the outer periphery thereof. The axis of the taper shank portion 12 coincides with the axis O of the small diameter tool holding chuck 10. The taper shank portion 12 is grasped by a spindle of a machine tool (not shown). A flange 13 and a V-shaped groove 14 having a V-shaped cross section extending in the circumferential direction are formed on the outer periphery of the tip of the chuck body 11. A circular recess 16 centered on the axis O is formed on the tip surface of the chuck body 11.

  The adapter 21 is a cylindrical member having a collet insertion hole 22 in the center. The collet insertion hole 22 extends along the axis O, and is formed into a tapered hole 22t whose tip region expands toward the tip side. On the other hand, the end region 22c of the collet insertion hole 22 has a substantially constant diameter dimension in the axial direction. A flange 23 is formed on the end side of the adapter 21. The end portion 24 of the adapter 21 protruding from the annular end surface 23t of the flange 23 toward the end side has a cylindrical shape. However, the outer diameter of the end portion of the end portion 24 is slightly tapered toward the end.

  The adapter 21 is securely connected and fixed to the chuck body 11. Specifically, the end portion 24 of the adapter 21 is fitted into the circular recess 16 of the chuck body 11. Further, the flat annular end surface 23 t of the adapter 21 is in surface contact with the flat annular tip surface 15 of the chuck body 11. The annular end face 23t and the tip face 15 are perpendicular to the axis O. The inner peripheral surface 16 i of the circular recess 16 has a constant diameter dimension in the axial direction and is formed coaxially with the axis O. The inner peripheral surface 16 i is centered so that the axis of the adapter 21 coincides with the axis of the chuck body 11.

  The taper collet 31 is inserted into the collet insertion hole 22 from the distal end side of the small diameter tool holding chuck 10 and extends along the collet insertion hole 22. In the center of the taper collet 31, a tool holding hole 32 extending from the tip to the end of the taper collet 31 is formed. In the tip region of the taper collet 31, a slit 33 extending in parallel with the axis O is formed. A plurality of slits 33 are provided at intervals in the circumferential direction. The outer diameter of the tip region of the taper collet 31 increases toward the tip. A female screw hole 34 is formed at the end of the taper collet 31. The female screw hole 34 extends continuously from the depth of the tool holding hole 32 and is screwed into the male screw part 43 of the pull screw 41.

  The pull screw 41 has a large-diameter head portion 42 and a small-diameter male screw portion 43 positioned below the neck. The head portion 42 is on the distal side of the small-diameter tool holding chuck 10, and the male screw portion 43 holds the small-diameter tool. It arrange | positions so that it may become the front end side of the chuck | zipper 10 for work. The large-diameter head 42 is formed with an end face 46 directed toward the tip side. The end surface 46 is an annular flat surface. The male screw portion 43 is inserted into the collet insertion hole 22 of the adapter 21. On the other hand, the head 42 is located on the distal side of the adapter 21 and is accommodated in the internal space 17. The internal space 17 is a circular recess formed so as to be further recessed toward the distal side at the bottom center of the circular recess 16.

  The large-diameter head portion 42 is engaged with the end portion 24 of the adapter 21 and is restricted from moving toward the front end side in the axis O direction. Thereby, the pulling screw 41 does not come out to the tip side. A flange 45 is formed near the neck of the head 42. The end surface of the flange 45 is provided flush with the end surface 46 of the head 42. A low friction member 51 is interposed between the flange 45 and the end portion 24. The low friction member 51 is for reducing the frictional resistance between the end surface 46 of the pull screw 41 and the end surface 25 of the end portion 24 when the pull screw 41 rotates, and corresponds to the outer diameter of the flange 45. A ring disk shape having an outer diameter and an inner diameter corresponding to the outer diameter of the neck lower portion 47 of the pull screw 41 is exhibited. The low friction member 51 is, for example, a metal bearing washer having a thickness of 0.1 to 0.5 mm. Low friction processing such as ion nitriding treatment, DLC (Diamond Like Carbon) coating treatment, TiN coating treatment, and mirror-like lapping treatment for reducing frictional resistance between the end face 46 and the end face 25 on both surfaces of the low friction member 51 Is given.

  The neck lower portion 47 of the pull screw 41 is located between the distal-side head portion 42 and the distal-side male screw portion 43, and has an outer diameter smaller than the head portion 42 and larger than the male screw portion 43. The outer peripheral surface of the neck lower portion 47 is in contact with the inner peripheral surface of the end region 22 c of the collet insertion hole 22. As a result, the axis of the neck portion 47 is centered so as to coincide with the axis O, and the axis of the pull screw 41 coincides with the axis O.

  The chuck body 11 is formed with a lateral hole 18 and an adjusting screw hole 19 extending from the outer peripheral surface to the internal space 17. The lateral hole 18 and the adjustment screw hole 19 extend along a reference line X that is orthogonal to the axis O and extends straight in the radial direction. That is, the lateral hole 18 and the adjustment screw hole 19 are arranged coaxially and face each other with the internal space 17 interposed therebetween.

  A pinion 61 serving as a bevel gear is disposed in the back of the horizontal hole 18. Umbrella-shaped teeth 63 formed at one outer edge of the pinion 61 mesh with a bevel gear 44 formed at the end of the head 42 of the pull screw 41. A polygonal hole 65 for rotating the pinion 61 is formed on the other end surface of the pinion 61.

  A female screw 18t is formed on the outer diameter side of the lateral hole 18, and a retaining ring 62 is screwed into the female screw 18t. The retaining ring 62 engages with the pinion 61 to prevent the pinion 61 from coming out of the lateral hole 18 to the outer diameter side. The axial position of the retaining ring 62 can be adjusted by rotating the retaining ring 62 in the tightening direction or the loosening direction.

  A low friction member 52 is interposed between the pinion 61 and the retaining ring 62. The low friction member 52 is for reducing the frictional resistance between the end surface 67 of the pinion 61 and the end surface 64 of the retaining ring 62 when the pinion 61 rotates, and has an outer diameter corresponding to the outer diameter of the pinion 61. And a ring disc shape having an inner diameter corresponding to the polygonal hole 65 of the pinion 61. Low friction processing such as ion nitriding treatment, DLC (Diamond Like Carbon) coating treatment, TiN coating treatment, and mirror-like lapping treatment for reducing frictional resistance between the end face 67 and the end face 64 is performed on both surfaces of the low friction member 52. Is given.

  The inner peripheral surface on the inner diameter side of the horizontal hole 18 in which the female screw is not formed has a constant inner diameter from one side of the reference line X to the other, contacts the outer peripheral surface of the pinion 61, and the axis of the pinion 61 is aligned with the reference line X Align to match.

  A conical recess 69 is formed in the central portion of one end surface of the pinion 61 where the umbrella-like teeth 63 are not formed. The conical recess 69 receives the tip of the meshing adjustment screw 71 that is screwed into the female screw of the adjustment screw hole 19.

  The engagement adjusting screw 71 has a large-diameter head 72, a small-diameter male screw portion 73, and a tapered conical tip portion 74. Then, the head 72 is disposed on the outer diameter side of the chuck body 11, the male screw portion 73 is screwed into the adjustment screw hole 19, and the conical tapered tip 74 comes into contact with the pinion 61.

  When a screwdriver (not shown) is inserted into the polygonal hole 75 formed in the head 72 and the engagement adjusting screw 71 is rotated in the tightening direction, the tip 74 presses the pinion 61 toward the outer diameter side, and the shaft of the pinion 61 Move the direction position. As a result, the pinion 61 moves away from the bevel gear 44, and the meshing between the bevel gear 44 and the pinion 61 becomes shallow. On the contrary, when the engagement adjusting screw 71 is rotated in the loosening direction, the pinion 61 can approach the bevel gear 44, and the engagement between the bevel gear 44 and the pinion 61 becomes deeper.

  A procedure for chucking the shank portion 101 of the small diameter tool using the small diameter tool holding chuck 10 will be described.

  First, the taper collet 31 is inserted into the collet insertion hole 22, and the female screw hole 34 at the end of the taper collet 31 is loosely screwed into the male screw portion 43 at the tip of the pulling screw 41.

  With the pull screw 41 loosened in advance by the pinion 61, the shank portion 101 of the small diameter tool is inserted into the tool holding hole 32. Next, a screwdriver is inserted into the central hole of the retaining ring 62, the tip of the adjustment tool is engaged with the polygonal hole 65 of the pinion 61, and the pinion 61 is rotated in the tightening direction. As a result, the bevel gear 44 rotates in the tightening direction, and the pull screw 41 pulls the tapered collet 31 into the depth of the collet insertion hole 22. At this time, the slit 33 of the taper collet 31 is pressed and shrunk to the taper hole 22t that becomes narrower toward the depth of the end hole, and the tool holding hole 32 is reduced in diameter. Therefore, the shank part 101 is grasped with a uniform force over the entire circumference.

  On the contrary, in order to unchuck the shank portion 101, the pinion 61 may be loosened and rotated in the direction of the adjustment tool.

  According to the small-diameter tool holding chuck 10 of the embodiment shown in FIG. 1, the adjustment screw hole 19 that extends from the outer peripheral surface of the chuck body 11 to the internal space 17 and is arranged coaxially with the lateral hole 18 across the internal space 17 is screwed. And a meshing adjustment screw 71 for mating. And the front-end | tip part 74 of the meshing adjustment screw 71 contact | abuts to the center part of the pinion 61, and the axial direction position of the pinion 61 regarding the reference line X is adjusted. Therefore, by rotating the engagement adjusting screw 71, the engagement between the bevel gear 44 and the pinion 61 can be adjusted to an appropriate state without being too shallow and not too deep.

  Further, according to the small-diameter tool holding chuck 10 of the present embodiment, the tip end portion 74 has a conical shape, and a conical recess 69 that receives the end of the engagement adjusting screw 71 is formed at the center of the pinion 61. As a result, even if the axis of the pinion 61 is slightly misaligned from the reference line X, the tip of the engagement adjusting screw 71 can always come into contact with the bottom of the conical recess 69 of the pinion 61. Further, friction can be reduced by making the contact point between the engagement adjusting screw 71 and the pinion 61 a point, and the user of the small diameter tool holding chuck 10 can efficiently rotate the pinion 61 with a small force.

  Further, the pinion 61 of the present embodiment has an outer peripheral surface that comes into contact with the inner peripheral surface of the horizontal hole 18, and is centered by the inner peripheral surface of the horizontal hole 18. As a result, the axis of the pinion 61 coincides with the reference line X, and the bevel gear 44 and the pinion 61 can be engaged in an appropriate state. The diameter of the inner peripheral surface of the horizontal hole 18 is constant from one side to the other in the axial direction, and the diameter of the outer peripheral surface of the pinion 61 is also constant from one side to the other in the axial direction. Does not hinder the axial movement of the pinion 61.

  Further, according to the chuck 10 for holding a small-diameter tool of the present embodiment, the adapter 21 is chucked by fitting the end portion 24 of the adapter 21 to the inner peripheral surface 16i of the circular recess 16 formed at the tip of the chuck body 11. It is arranged coaxially with the main body 11. The pull screw 41 has a neck lower portion 47, and the pull screw 41 is centered when the outer peripheral surface of the neck lower portion 47 comes into contact with the inner peripheral surface of the end portion 24. As a result, the adapter 21 is centered so that the axis of the adapter 21 matches the axis O. Further, the shaft center of the bevel gear 44 provided on the pull screw 41 is centered so as to coincide with the axis O. Therefore, the bevel gear 44 and the pinion 61 can be meshed in an appropriate state.

  Further, the pull screw 41 of the present embodiment further has an end face 46 directed to the tip side between the bevel gear 44 and the male screw portion 43. The end surface 46 of the pull screw 41 is an annular flat surface, and the axial movement toward the distal end side is restricted by the end portion 24 of the adapter 21. Between the end surface 46 and the end surface 25 of the adapter 21, a low friction member 51 including a surface treatment portion subjected to low friction treatment is interposed. Thereby, when the pull screw 41 rotates, the friction between the pull screw 41 and the end face 25 of the adapter 21 can be reduced. Accordingly, the rotation efficiency when the pull screw 41 rotates while pulling the taper collet 31 is improved, and the user of the small diameter tool holding chuck 10 can chuck the shank portion 101 of the small diameter tool with a small force.

  Further, according to the small-diameter tool holding chuck 10 of the present embodiment, the female screw 18t is formed on the outer peripheral surface side of the chuck body 11 in the inner peripheral surface of the horizontal hole 18, and the pinion 61 is prevented from coming off in the female screw 18t. An annular retaining ring 62 is screwed. Further, the end surface 67 of the pinion 61 directed to the outer peripheral surface side of the chuck body 11 includes an annular flat surface. And between the annular flat surface (end surface 67) of the pinion 61 and the end surface of the retaining ring 62, a low friction member 52 including a surface treatment portion subjected to low friction treatment is interposed. Thereby, when the pinion 61 rotates, the friction between the pinion 61 and the retaining ring 62 can be reduced. Therefore, the rotation efficiency when tightening and rotating the pinion 61 is improved, and the user of the small diameter tool holding chuck 10 can efficiently rotate the pinion 61 with a small force.

  Next, a modification of the present invention will be described. FIG. 2 is a longitudinal sectional view showing a modification of the present invention. In the modification shown in FIG. 2, a cutting fluid passage is added to the embodiment shown in FIG. The chuck body passage 81a, which is a cutting fluid passage, changes its direction from the depth of the pull stud hole 11h extending from the end of the taper shank portion 12 along the axis O, and inclines toward the distal end side of the small diameter tool holding chuck 10. Extending to connect with the chuck body passage 81b.

  The chuck body passage 81b changes its direction from the chuck body passage 81a, extends parallel to the axis O to the tip surface 15, and is connected to an adapter passage 82 formed in the annular end surface 23t. The adapter passage 82 changes its direction from the chuck main body passage 81 b and extends while inclining toward the tip end side of the small diameter tool holding chuck 10, and is connected to the collet insertion hole 22. Thus, one cutting fluid passage that extends from the chuck body 11 to the adapter 21 and avoids the bevel gear 44 is formed.

  The chuck body passages 81 a and 81 b are disposed at positions away from the axis O, bypass the internal space 17, and do not intersect the bevel gear 44. The chuck body passages 81 a and 81 b are formed at different circumferential positions from the lateral hole 18 and the adjustment screw hole 19, and do not intersect with the pinion 61 and the engagement adjustment screw 71. The adapter passage 82 is formed in the cylindrical thick portion of the adapter 21 and bypasses the end portion 24.

  According to the modification shown in FIG. 2, the cutting fluid is supplied to the small-diameter tool holding chuck 10 from the main shaft (not shown), and the cutting fluid is a pull stud hole 11h, a chuck body passage 81a, a chuck body passage 81b, and an adapter. It flows into the collet insertion hole 22 through the passage 82. The tip surface 15 and the annular end surface 23t are in surface contact. Accordingly, it is possible to easily ensure the sealing performance at the connection portion between the chuck body passage 81b and the adapter passage 82. Further, since the chuck body passages 81a and 81b extend around the engagement adjusting screw 71 and the bevel gear 44, the cutting fluid does not leak in the middle of the chuck body passages 81a and 81b.

  Next, further modifications of the present invention will be described. FIG. 3 is a longitudinal sectional view showing a further modification of the present invention. The small-diameter tool holding chuck 20 shown in FIG. 3 has a longer axial length than the small-diameter tool holding chuck 10 shown in FIG. 2 and further includes drawing screw passages 83a and 83b through which cutting fluid flows. Specifically, the axial length of the adapter 21 of the small-diameter tool holding chuck 10 is La, whereas the axial length of the adapter 26 of the small-diameter tool holding chuck 20 is Lb (La <Lb). For this reason, the end region 22 c of the collet insertion hole of the small diameter tool holding chuck 20 is longer than that of the small diameter tool holding chuck 10. The pull screw 48 of the small-diameter tool holding chuck 20 has an intermediate portion 49 between the neck lower portion 47 and the male screw portion 43, and the size of the neck below the neck of the pull screw 41 of the small-diameter tool holding chuck 10 described above. Longer than the dimension.

  The adapter passage 82a extends in parallel with the axis O from the annular end surface 23t toward the tip end side, and is connected to the adapter passage 82b. The adapter passage 82b changes its direction from the adapter passage 82a and extends in the inner diameter direction of the adapter 26, and is connected to the end region 22c of the collet insertion hole.

  Of the pull screw 48, pull screw passages 83a and 83b are formed in a region accommodated in the end region 22c of the collet insertion hole. The pull screw passage 83 a is formed in the intermediate portion 49, extends in the radial direction of the pull screw 48, and penetrates the intermediate portion 49. In the embodiment shown in FIG. 3, two pull screw passages 83 a are formed at an interval in the axial direction of the pull screw 48. The pull screw passage 83 b extends from these pull screw passages 83 a and 83 a to the tip of the pull screw 48. The pull screw passage 83 b extends along the axis of the pull screw 48.

  According to the further modification shown in FIG. 3, the cutting fluid is supplied to the small-diameter tool holding chuck 20 from the main shaft side (not shown). Then, the cutting fluid flows out to the end region 22c of the collet insertion hole through the pull stud hole 11h, the chuck body passage 81a, the chuck body passage 81b, the adapter passage 82a, and the adapter passage 82b. Next, the cutting fluid flows into the pull screw passage 83 a, flows through the pull screw passage 83 b, and flows out to the tool holding hole 32. Since the front end surface 15 and the annular end surface 23t are in surface contact with each other, it is possible to easily ensure the sealing performance at the connection portion between the chuck body passage 81b and the adapter passage 82a. Further, since the chuck body passages 81a and 81b extend around the engagement adjusting screw 71 and the bevel gear 44, the cutting fluid does not leak in the middle of the chuck body passages 81a and 81b. Further, even when the axial length of the adapter 26 is longer than that of the normal adapter 21 (Lb> La), the cutting fluid can be supplied to the shank portion 101 of the small diameter tool.

  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 chuck for holding a small diameter tool according to the present invention is advantageously used in a machine tool.

10 Small diameter tool holding chuck, 11 Chuck body,
11h Pull stud hole, 15 Tip surface, 14 V-groove,
16 circular recess, 16i inner peripheral surface, 17 internal space,
18 side hole, 18t female thread, 19 adjustment screw hole,
20 Small diameter tool holding chuck, 21 Adapter,
22 collet insertion hole, 22c end region, 22t taper hole,
23 flange, 23t annular end face, 24 end,
25 end face, 26 adapter, 31 taper collet,
32 Tool holding hole, 33 Slot, 34 Female screw hole,
41 Pull screw, 42 Head, 43 Male thread,
44 bevel gear, 45 flange, 46 end face,
47 lower neck, 48 pull screw, 49 middle part,
51, 52 low friction member, 61 pinion,
62 retaining ring, 63 teeth, 64 end face,
65 polygonal holes, 67 end faces, 69 conical recesses,
71 meshing adjustment screw, 72 head, 73 male thread,
74 tip, 81a, 81b chuck body passage,
82, 82a, 82b adapter passage,
83a, 83b Pull screw passage, 101 Shank,
O axis, X reference line.

Claims (8)

A chuck body having a shank portion provided in an end region;
A cylindrical adapter that has a collet insertion hole with an enlarged tip extending from the tip toward the end and is fixedly attached to the tip of the chuck body;
A taper collet having a tool holding hole extending from the distal end toward the distal end, and a female screw hole extending from the distal end toward the distal end, and inserted into the collet insertion hole;
A bevel gear housed in the internal space of the chuck body, and a pull having a male screw portion extending from the bevel gear to the distal end side and inserted into the collet insertion hole from the distal end side of the adapter and screwed into the female screw hole of the tapered collet. Screws,
A pinion rotatably accommodated in a lateral hole extending from the outer peripheral surface of the chuck body to the internal space, meshing with the bevel gear, and rotating the pull screw to reduce the diameter while drawing the tapered collet into the collet insertion hole; ,
The chuck body extends from the outer peripheral surface of the chuck body to the internal space and is screwed into an adjustment screw hole disposed coaxially with the lateral hole with the internal space interposed therebetween, and an end portion of the pinion comes into contact with the center portion of the pinion. A small-diameter tool holding chuck comprising a meshing adjustment screw for adjusting an axial position. The end of the engagement adjusting screw has a conical shape,
2. The small diameter tool holding chuck according to claim 1, wherein a conical concave portion that receives an end portion of the engagement adjusting screw is formed at a center portion of the pinion.   The small-diameter tool holding chuck according to claim 1, wherein the pinion has an outer peripheral surface that contacts an inner peripheral surface of the horizontal hole, and is centered by the inner peripheral surface of the horizontal hole. The adapter is disposed coaxially with the chuck body by fitting the end portion of the adapter to the inner peripheral surface of a circular recess formed at the tip of the chuck body.
The said pull screw further has an outer peripheral surface which contacts the internal peripheral surface of the terminal part of the said adapter made into the cylindrical shape, and is centered by the internal peripheral surface of the terminal part of the said adapter. The small diameter tool holding chuck according to any one of the above.   A passage through which a cutting fluid flows, the chuck body passage formed in the chuck body, and a cylindrical thick portion of the adapter, one end connected to the chuck body passage and the other end connected to the collet insertion hole The chuck for holding a small-diameter tool according to claim 4, further comprising: an adapter passage that performs the operation.   6. The passage according to claim 5, further comprising a passage through which a cutting fluid flows, wherein the lead screw passage is formed in the pull screw and has one end extending to an outer peripheral surface of the pull screw and the other end extending to a tip portion of the pull screw. Chuck for holding small diameter tools. The pull screw further has an annular flat surface directed to the tip side between the bevel gear and the male screw portion,
The annular flat surface is restricted from moving in the axial direction toward the tip by the end of the adapter,
The small diameter tool holding chuck according to any one of claims 4 to 6, wherein a surface treatment portion subjected to a low friction treatment is interposed between the annular flat surface and the end face of the end portion of the adapter. A female screw portion is formed on the outer peripheral surface side of the chuck body in the inner peripheral surface of the lateral hole, and an annular retaining member for retaining the pinion is screwed into the female screw portion,
The end surface of the pinion directed toward the outer peripheral surface side of the chuck body includes an annular flat surface,
The chuck for holding a small-diameter tool according to any one of claims 1 to 7, wherein a surface treatment portion subjected to a low friction treatment is interposed between the annular flat surface of the pinion and an end surface of the retaining member.

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