JP2012061525A - Spot-facing tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spot-facing tool which enables the cutter thereof to advance/retract radially with a simple structure.SOLUTION: The spot-facing tool 11 includes: a main shaft 12 which is extended along the axis and has such an insertable shape that the axial direction-back end of the main shaft can be inserted into a holder of a machine tool; the cutter 13 which is supported turnably at the axial-direction front end of the main shaft and has such a storage position that the cutter falls down along the main shaft and such a projection position that the cutter erects on the main shaft; and a guide sleeve 16 which is a cylindrical body arranged relatively rotatably to the outer periphery of the main shaft, has a window 28 on the side face thereof, covers the cutter 13 at a first rotational position being one circumferential direction-position to hold the cutter at the storage position and exposes the cutter 13 from the window 28 at a second rotational position being another circumferential direction-position to project the cutter from the window to the radial direction-outside thereby holding the cutter at the projection position.

Description

  The present invention relates to a cutting tool to be mounted on a holder of a machine tool, and more particularly, to a counterbore cutting tool that inserts a workpiece into a prepared hole and causes a cutting tool to protrude and retract to perform back-facing on the back side of the prepared hole.

  In the counterbore machining, a pilot hole that penetrates the front and back surfaces of the workpiece is formed in advance with an NC machine, etc., and a counterbored arbor attached to the holder of the machine tool is inserted into the pilot hole of the workpiece from the front side. The tip of the counterbore arbor is protruded from the back surface of the workpiece, and the cutting tool is radially extended from the tip of the counterbore arbor to project the back surface of the workpiece. After finishing the counterbore, insert the cutting tool into the tip of the counterbore arbor and pull out the counterbore arbor from the pilot hole.

  Conventionally, there are various techniques for automatically carrying out the protrusion and withdrawal of the cutting tool in the back spot machining. For example, in Japanese Patent Laid-Open No. 11-156612 (Patent Document 1), the pressure of the coolant liquid is used as a drive source to cause the cutting tool to protrude radially outward from the arbor tip, or the cutting tool is radially inward of the arbor tip. Immerse you.

Japanese Patent Laid-Open No. 11-156612

  However, the counterbore arbor that uses the pressure of the coolant liquid to enter and exit the blade as in the above-described conventional technique includes a cylinder chamber that guides the fluid pressure into the tool, a piston that converts the fluid pressure into a linear motion, and a piston and a blade. Since a rod or the like for connecting and operating the blade is necessary, the structure becomes complicated and the cost is increased.

  In view of the above circumstances, an object of the present invention is to provide a counterbore cutting tool capable of causing a cutting tool to appear and disappear in a radial direction with a simple structure.

  For this purpose, the counterbore cutting tool according to the present invention extends along the axis, and the axial rear end of the main shaft has an insertion shape that can be attached to the holder of the machine tool, and the main shaft is rotated to the front end in the axial direction. A retractable position that is supported in a movable manner and that falls down along the main shaft; a cutting tool that is set to a protruding position that stands up with respect to the main shaft; and a biasing member that urges the blade to turn up and bias it to the protruding position; A cylindrical body provided on the outer periphery of the main shaft so as to be relatively rotatable, having a window on the side surface, and covering the blade tool at one of the first rotation positions in the circumferential direction to hold the blade tool in the storage position, and in the circumferential direction A guide sleeve that protrudes radially outward from the window by exposing the blade from the window at the other second rotational position.

  According to the present invention, since the guide sleeve provided on the outer periphery of the main shaft so as to be relatively rotatable causes the cutting tool to appear and disappear, a complicated structure can be eliminated, which is advantageous in terms of cost.

  In counterbore machining, select the outer diameter of the counterbore cutting tool to be slightly smaller than the inner diameter of the pilot hole in the workpiece, and between the inner surface of the lower hole and the outer diameter of the counterbore cutting tool. It is customary to avoid the occurrence of rotational resistance and to make the counterbore arbor easily removable from the pilot hole. Conventionally, however, rotational resistance or welding may occur between the inner peripheral surface of the prepared hole and the outer peripheral surface of the counterbore arbor during counterboring.

  In order to solve this problem, as a preferred embodiment, a low-friction portion provided on the outer peripheral surface of the guide sleeve and at least in a region in contact with the lower hole of the workpiece to be processed to reduce friction with the workpiece is further provided. Prepare. According to this embodiment, since the low friction portion is provided on the outer peripheral surface of the guide sleeve which is a cylindrical body, when the countersink is machined by inserting the counterbore cutting tool into the prepared hole of the workpiece, The rotational resistance between the inner peripheral surface of the hole and the outer peripheral surface of the guide sleeve can be suitably reduced.

  Note that the low friction portion is provided at least in a region of the outer peripheral surface of the guide sleeve that is in contact with the prepared hole to be machined. As an example, the low friction part is provided over the entire circumference of the outer peripheral surface of the guide sleeve, and is preferably provided in the axial direction region on the rear end side of the window.

  In one embodiment, the low friction part is a surface treatment layer formed on the outer peripheral surface of the guide sleeve. The surface treatment layer includes, for example, ion nitriding, DLC (Diamond Like Carbon) coating, TiN (titanium nitride) coating, and mirror-like lapping.

  In another embodiment, the low friction portion is a pipe member attached on the outer peripheral surface of the guide sleeve. The pipe member may be fitted and fixed to the outer periphery of the guide sleeve and rotated together with the guide sleeve, or may be fitted to the outer periphery of the guide sleeve so as to be relatively rotatable.

  When the cutting tool is projected and retracted, the guide sleeve may be manually rotated relative to the main shaft by the operator, or may be automatically rotated relative to the main shaft by the operation of the machine tool. As a preferred embodiment, the guide sleeve includes a step that contacts the surface of the workpiece when moving forward, and the step is provided with a cushioning material that mitigates the collision with the workpiece. According to this embodiment, when the counterbore cutting tool is inserted into the prepared hole of the workpiece from the surface and the step is pressed against the surface of the workpiece, the surface of the workpiece is not damaged. Then, the cutting tool can be made to appear and disappear automatically when the machine tool relatively rotates the main shaft or the guide sleeve.

  By the way, after completion of the counterbore processing, the cutting tool is stored in the storage position. However, the cutting tool does not necessarily immerse into the storage position, for example, when chips are bitten. If it does so, when extracting a counterbore cutting tool, there exists a possibility that a cutting tool may collide with a counterbore hole and a counterbore cutting tool may be damaged. Therefore, as a preferred embodiment, the main shaft has a main portion, a blade support portion that supports the blade, and a connecting portion that connects the main portion and the blade support portion, and the connection portion includes the main portion and the blade support portion. When an excessive pulling force is applied between the two, the connection between the two is released. According to such an embodiment, when the cutting tool is automatically retracted, even if the cutting tool does not completely immerse to the storage position and protrudes from the window to the outer diameter side, it is countersunk from the pilot hole. When pulling out the cutting tool, the cutting tool collides with the back surface of the workpiece, and an excessive pulling force that tries to separate the main part of the main shaft from the cutting tool support part is applied to the connecting part. As a result, the main part of the main shaft and the blade support portion are separated, and the blade is detached from the main shaft. Therefore, serious breakage of the spot facing cutting tool or the workpiece can be prevented.

  The connection structure of the main shaft and the guide sleeve is not particularly limited, but as a preferred embodiment, a groove extending in the circumferential direction is formed on one of the inner peripheral surface of the guide sleeve or the outer peripheral surface of the main shaft. A protrusion that engages with the groove is formed on the other of the inner peripheral surface or the outer peripheral surface of the main shaft, and the protrusion is selectively held at one end and the other end of the groove. According to this embodiment, since the protrusion engages with the groove extending in the circumferential direction and is selectively held at one end and the other end of the groove, the cutting tool can be easily rotated to the storage position or the protruding position. Can be held. One end of the groove corresponds to the first rotation position of the guide sleeve, and the other end of the groove corresponds to the second rotation position of the guide sleeve.

  The method of supplying the cutting fluid to the counterbore hole in the counterbore processing is not particularly limited. However, as a preferred embodiment, the main shaft extends from the rear end in the axial direction toward the front end, and ejects the cutting fluid to the cutting tool at the protruding position. A cutting fluid passage. According to this embodiment, it becomes possible to supply cutting fluid efficiently to a counterbore hole, and counterbore processing can be performed suitably.

  The structure of the blade is not particularly limited, but as a preferred embodiment, the blade has blade portions on the axial rear end side and the axial front end side, respectively. According to such an embodiment, both front face facing and back face facing are possible.

  The structure of the cutting tool is not particularly limited, but as a preferred embodiment, the cutting tool has a cutting tool body and an insert tip that is attached to the cutting tool body and cuts a workpiece.

  As described above, according to the present invention, since the cutting tool attached to the main shaft is caused to appear and disappear by the guide sleeve relatively rotatable in the circumferential direction, a complicated cylinder mechanism can be eliminated, which is advantageous in terms of cost. According to the present invention, the guide sleeve may be relatively rotated automatically or manually.

It is a top view which shows the counterbore arbor which becomes one Example of this invention. It is a principal part side view which shows the spot facing arbor which becomes the same Example in a partial cross section. It is sectional drawing in III-III of FIG. It is sectional drawing in IV-IV of FIG. It is a top view which shows the counterbore arbor in which the cutting tool was made into the protrusion position. It is a side view which shows the counterbore arbor in which the blade tool was made into the protrusion position in a partial section. It is a front view which shows the counterbore arbor in which the cutting tool was made into the protrusion position. It is sectional drawing in VIII-VIII of FIG. It is sectional drawing in IX-IX of FIG. It is explanatory drawing which shows a mode that a tool is made to appear and disappear automatically. It is a side view which shows the cutting fluid path | route of the spot facing arbor which becomes the Example. It is a figure which shows the modification of a blade. It is a principal part side view which shows the spot facing arbor which becomes another Example by a partial cross section. It is a disassembled perspective view which shows typically the counterbore arbor which becomes another Example.

  Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.

  A counterbore arbor 11 that becomes a counterbore cutting tool has an elongated cylindrical main shaft main portion 12 extending along a rotation axis (hereinafter referred to as an axis) indicated by a one-dot chain line in FIGS. 1 and 2. A shank portion 14 is formed at the rear end portion in the axial direction while having a cutting tool 13 that can project and exit in the radial direction. The shank portion 14 has a cylindrical surface 14a represented by a predetermined radius and a flat inclined surface 14b formed so as to cut and cut the cylindrical surface, and is inserted into the tip of a holder of a machine tool (not shown). Is attached. The shank portion 14 can be chucked on a wide variety of holders.

  A flange portion 17 is formed adjacent to the front end side of the outer peripheral surface of the main shaft main portion 12 with respect to the shank portion 14. The outer diameter dimension of the flange portion 17 is larger than the outer diameter dimension of the shank portion 14. Further, the outer diameter of the main shaft main portion 12 includes a flange portion 17, a cylindrical axial region 12a adjacent to the distal end side of the flange portion, and a cylindrical axial center region adjacent to the distal end side of the region 12a. 12b and the columnar axial tip region 12c adjacent to the tip side of the axial center region 12b become smaller in order.

  A concave portion 19 that is recessed in the inner diameter direction is formed at the main shaft tip portion included in the axial tip region 12 c of the main shaft main portion 12. A cylindrical shaft tip member 22 is attached to the tip of the main shaft main portion 12 via a screw 21. The outer diameter of the shaft tip member 22 that is the tip of the main shaft is the same as the outer diameter of the axial tip region 12c. The shaft tip member 22 is adjacent to the recess 19. A pivot 23 is installed between the shaft tip member 22 and the main shaft main portion 12 so as to pass through the recess 19. The pivot 23 extends in parallel with the axis and pivotally supports the blade 13. As a result, the cutting tool 13 falls down along the main shaft as shown in FIGS. 2 and 3 and is stored in the recess 19 and with respect to the main shaft main part 12 as shown in FIGS. It rises and pivots to a protruding position protruding from the recess 19.

  The distal end portion of the pivot 23 passes through a through hole 22h formed in the shaft distal end member 22 and extending parallel to the axis. A retaining screw 23t is screwed into the through hole 22h from the front end side. This prevents the pivot 23 from coming out of the through hole 22h.

  The rear end portion of the pivot 23 is inserted into a hole 12 h that is recessed rearward from the front end of the main shaft main portion 12.

  A spring 29 is provided in an annular gap between the through hole 22 h inside the shaft tip member 22 and the pivot 23. The spring 29 is an urging member that engages with the cutting tool 13 and the shaft tip member 22, respectively, and urges the cutting tool 13 to rotate and urge to the protruding position.

  The shaft tip member 22 is fixed to the tip of the main shaft main portion 12 by a screw 21. However, the shaft tip member 22 separates from the main shaft main portion 12 when an excessive pulling force is applied. That is, in this embodiment, the spot facing arbor 11 connects the main shaft main portion 12, the shaft tip member 22 and the pivot 23 included in the blade support portion that supports the blade 13, and the main portion and the blade support portion. And the screw 21 is configured to release the connection between the main part and the blade support part when an excessive pulling force is applied.

  A guide sleeve 16, which is a cylindrical body with openings at both ends, is put on a portion of the main shaft main portion 12 that is more distal than the flange portion 17. The guide sleeve 16 is provided across the axial region 12a, the axial central region 12b, and the axial tip region 12c of the main shaft main portion 12, and is supported on the outer peripheral surface of the main shaft main portion 12 so as to be relatively rotatable. The A flange portion 32 is formed at the rear end in the axial direction of the guide sleeve 16.

  The outer diameter of the outer peripheral surface of the guide sleeve 16 is the largest at the flange portion 32 at the rear end in the axial direction and the smallest at the front end side in the axial direction. Specifically, the outer diameter dimension of the flange portion 32, the outer diameter dimension of the cylindrical region 16a located on the axial direction tip side from the flange portion 32, and the cylindrical shape located on the axial direction tip side from the region 16a. In the order of the outer diameter of the region 16b, the region 16b becomes smaller in steps. An annular step 34 is formed at the boundary between the region 16a and the region 16b on the outer periphery of the guide sleeve. The annular step 34 is provided with a cushioning material 35 that alleviates the collision with the workpiece.

  Whereas the guide sleeve 16 including the flange portion 32 is made of metal, the cushioning material 35 is made of a softer material than metal, such as a soft resin such as urethane or an elastic material such as rubber. As will be described in detail later, the surface of the cushioning material 35 is an annular flat surface perpendicular to the axis, and comes into contact with the surface of the workpiece (the counterbore arbor 11 side) when the counterbore arbor 11 moves forward.

  Of the outer peripheral surface of the guide sleeve 16, at least a surface region 16 s in contact with the prepared hole to be machined is subjected to a surface treatment so as to reduce friction. The surface treatment applied to the surface treatment layer 16s as the low friction portion is, for example, a low friction treatment such as an ion nitriding treatment, a DLC (Diamond Like Carbon) coating treatment, a TiN (titanium nitride) coating treatment, and a mirror-like lapping treatment. is there. This surface treatment is performed over the entire 360 ° circumference of the outer peripheral surface. The surface treatment layer 16s may be formed on the entire region 16b, or may be formed on a part of the region 16b, but is formed at least in the axial region between the cushioning material 35 and the window 28.

  An annular space is defined between the inner peripheral surface of the guide sleeve 16 and the outer peripheral surface of the axial center region 12b of the main shaft main portion 12, and a spring 24 is contracted in the annular space. The rear end in the axial direction of the spring 24 abuts on the annular step at the boundary between the region 12 a and the central region 12 b in the axial direction, while the front end in the axial direction of the spring 24 contacts the annular step provided on the inner periphery of the guide sleeve 16. The guide sleeve 16 is urged toward the distal end side of the main shaft main portion 12.

  A screw hole 25 (see FIGS. 4 and 9) penetrating in the radial direction is formed in the guide sleeve 16 on the tip side of the spring 24, and a screw 26 is screwed into the screw hole 25. The head of the screw 26 is fixed to the guide sleeve 16, and the tip 26 t of the screw 26 engages with a groove 27 formed in the axial center region 12 b of the outer peripheral surface of the main shaft main portion 12. The groove 27 is provided in the axial center region 12b, extends in the circumferential direction, and the one end 27a and the other end 27b slightly extend forward in the axial direction.

  Since the screw tip 26t is guided along the groove 27, the rotation angle of the guide sleeve 16 is restricted between the one end 27a and the other end 27b. Further, the guide sleeve 16 is made non-slidable relative to the axial direction except when the screw tip 26t is positioned at both ends 27a and 27b of the groove 27.

  On the other hand, when the screw tip 26t is located at both end portions 27a and 27b of the groove 27, the guide sleeve 16 is slightly slidable in the axial direction. Then, the screw tip 26 is urged toward the tip end side in the axial direction by the spring 24 and is fitted to the one end portion 27a or the other end portion 27b. As a result, the guide sleeve 16 is prevented from rotating relative to the circumferential direction.

  A window 28 is formed on the side surface of the distal end portion of the guide sleeve 16. The window 28 is in the vicinity of the recess 19 and blocks or opens the recess 19 by the relative rotation of the guide sleeve 16. 1 to 4, when the screw tip 26 t of the screw 26 fixed to the guide sleeve 16 is positioned at the one end portion 27 a, the guide sleeve 16 is brought to the first rotational position in the circumferential direction, and the window 28. The recess 19 is blocked by the circumferential position of the recess 19 and the recess 19 being different. Thus, the guide sleeve 16 covers the cutting tool 13 to hold the cutting tool 13 in the storage position in the recess 19.

  When the cutting tool 13 is protruded, the guide sleeve 16 is rotated relative to the main shaft main portion 12. If it does so, the circumferential direction position of the window 28 and the circumferential direction position of the recessed part 19 will correspond, and the blade tool 13 will be exposed. Then, the blade 13 is turned upright by the urging force of the spring 29.

  5 to 9, when the screw tip 26t of the screw 26 fixed to the guide sleeve 16 is positioned at the other end portion 27b, the guide sleeve 16 is moved to the other circumferential second rotation position, and the window The circumferential positions of 28 and the concave portion 19 coincide with each other to open the concave portion 19. Thus, by exposing the blade 13 from the window 28, the blade 13 is projected radially outward from the window 28 to a projecting position.

  Referring to FIG. 8, the spot facing is performed by rotating main part 12 of the main shaft counterclockwise while bringing cutting tool 13 into contact with the workpiece. The cutting tool 13 receives a clockwise force from the workpiece during cutting, but supports the cutting tool 13 whose wall surface defining the recess 19 is in the protruding position. As a result, the cutting tool 13 can be stably spotted without being pushed down by a clockwise force.

  When the cutting tool 13 is to be immersed, the guide sleeve 16 is rotated relative to the main shaft main portion 12, and the screw tip 26t is moved from the other end 27b to the one end 27a. At this time, the cutting tool 13 is pushed down by the window frame 28p of the window 28 that rotates counterclockwise with respect to the main shaft main portion 12 in FIG. 8, and resists the biasing force of the spring 29 to the main shaft main portion 12. Falls along. Thereby, the blade 13 is returned to the storage position.

  In the counterboring process using the counterbore arbor 11 of the present embodiment, as shown in FIG. 10, the tool tool holder 101 advances the counterbore arbor 11 to move the annular step 34 into the workpiece 201 as shown in FIG. 10. This can be done automatically by pressing against the front surface 203 of the front side (the counterbore arbor side).

  The back spot facing procedure will be described with reference to FIG. 10. First, the machine tool holder 101 inserts the spot facing arbor 11 into the lower hole 202 of the workpiece 201 with the cutting tool in the storage position. The inner diameter of the lower hole 202 is slightly larger than the outer diameter of the surface region 16 s of the guide sleeve 16, the axial direction region 16 b of the guide sleeve 16 penetrates the lower hole 202, and the window 28 and the shaft tip member 22 are the back surface 204. Protrude from.

  Subsequently, the counterbore arbor 11 is advanced, and the annular step 34 is pressed against the front surface 203 on the front side (the counterbore arbor side) of the workpiece 201. Then, the guide sleeve 16 cannot advance beyond the front surface 203, and the main shaft main part 12 advances. As a result, the spring 24 is compressed and the guide sleeve 16 is slightly retracted relative to the main shaft main portion 12. Thereby, the fitting of the screw tip 26t and the one end portion 27a is released.

  Next, the holder 101 of the machine tool rotates the main shaft main portion 12 relative to the guide sleeve 16 in one rotation direction. As a result, the screw tip 26t moves from the one end portion 27a along the groove 27 to be the other end portion 27b. Further, the window 28 moves to the circumferential position of the recess 19 and the cutting tool 13 is set to the protruding position.

  Next, when the holder 101 of the machine tool retracts the counterbore arbor 11, the guide sleeve 16 is urged toward the tip by the spring 24, and the screw tip 26t of the screw 26 is fitted to the other end 27b. Then, the counterbore arbor 11 is moved backward while being rotated at the cutting feed rate, the cutting tool 13 is brought into contact with the back surface 204, and the back surface 204 is subjected to back spot facing processing.

  When the back spot facing process is completed, the holder 101 of the machine tool advances the counterbore arbor 11 and presses the annular step 34 against the front surface 203 of the workpiece 201 (the counterbore arbor side). Then, the guide sleeve 16 cannot advance beyond the front surface 203, and the main shaft main part 12 advances. As a result, the spring 24 is compressed and the guide sleeve 16 is slightly retracted relative to the main shaft main portion 12. Thereby, the fitting of the screw tip 26t and the other end 27b is released.

  Next, the holder 101 of the machine tool rotates the main shaft main portion 12 relative to the guide sleeve 16 in the other rotation direction. As a result, the screw tip 26t moves from the other end portion 27b along the groove 27 to become one end portion 27a. Further, the window 28 is moved away from the circumferential position of the recess 19, and the cutting tool 13 is set to the storage position.

  Next, when the holder 101 of the machine tool retracts the counterbore arbor 11, the guide sleeve 16 is urged toward the tip end side by the spring 24, and the screw tip 26t of the screw 26 is fitted to the one end 27a. Then, the counterbore arbor 11 is retracted at a fast feed speed and is pulled out from the prepared hole 202.

  In the back facing process described above, the holder 101 of the machine tool rotates while pressing the annular step 34 of the guide sleeve 16 against the workpiece 201 so that the cutting tool 13 is automatically projected and retracted. However, the counterbore arbor 11 of this embodiment is not limited to the one that automatically causes the cutting tool 13 to appear and disappear, but the main shaft 12 is fixed and the operator manually rotates the guide sleeve 16 so that the cutting tool 13 appears and disappears. It is not excluded to make it happen.

  In this embodiment, when the cutting tool is immersed, the cutting tool 13 may not be completely immersed into the storage position due to clogging of chips, and may protrude from the window to the outer diameter side. In such an emergency case, the screw 21 can escape from the main shaft main part 12 to minimize the damage to the counterbore arbor 11 and the workpiece 201.

  Specifically, when the counterbore arbor 11 is retracted at a rapid feed speed in a state where the blade 13 protrudes from the window 28 to the outer diameter side, the blade 13 collides with the bottom surface of the counterbore hole on the back surface 204 and is larger than usual. An axial pulling force is applied to the screw 21. Then, the tip of the screw 21 comes out of the main shaft main portion 12, and the screw 21, the shaft tip member 22, the pivot 23, and the cutting tool 13 are separated from the main shaft main portion 12 and left on the back surface 204 side. Then, the main shaft main portion 12 and the guide sleeve 16 are pulled out from the lower hole 202.

  FIG. 11 is a side view showing the cutting fluid passage of the counterbore arbor 11. The main shaft main portion 12 has a cutting fluid passage 36 extending from the rear end of the shank portion 14 toward the front end side in the axial direction. The cutting fluid passage 36 is provided in the main shaft main portion 12 and extends in the axial direction, and a tip end portion 36f of the cutting fluid 36 changes its direction by 90 degrees and extends in a direction perpendicular to the axis. The cutting fluid passage tip 36f is exposed from the window 28 and directed toward the cutting tool 13 at the protruding position. The cutting fluid passage 36 is supplied with the cutting fluid from the holder 101 during the counterboring process, and ejects the cutting fluid to the cutting tool 13 in the direction of the arrow. Thereby, the cutting tool 13 is cooled during the back spot machining.

  As is apparent from the above description, according to the counterbore arbor 11 of the present embodiment, it is a cylindrical body provided on the outer periphery of the main shaft main portion 12 so as to be relatively rotatable, and has a window 28 on a side surface. The blade tool 13 is held in the storage position by covering the blade tool 13 at one circumferential first rotation position (see FIGS. 1 to 4), and the window 28 at the other circumferential second rotation position (see FIGS. 5 to 9). A guide sleeve 16 is provided in which the cutting tool 13 is exposed from the window to project the cutting tool radially outward from the window. As a result, the cutting tool can appear and disappear with a simple structure, which is advantageous in terms of cost.

  Further, according to the present embodiment, as a low friction part that is provided on the outer peripheral surface of the guide sleeve 16 and at least in a region in contact with the lower hole 202 of the workpiece 201 to be machined and reduces the friction with the workpiece 201, A surface treatment layer 16 s formed on the outer peripheral surface of the guide sleeve 16 is further provided. Thereby, when the counterbore arbor 11 is inserted into the lower hole 202 of the workpiece 201 and the counterbore is machined, the rotational resistance between the inner peripheral surface of the lower hole 202 and the outer peripheral surface of the guide sleeve 16 is suitably set. Can be reduced.

  Further, according to the present embodiment, the guide sleeve 16 includes the annular step 34 that abuts on the surface 203 of the workpiece 201 when moving forward, and the buffer step 35 that reduces the collision with the workpiece 201 is provided on the annular step 34. ing. Thereby, when the annular level | step difference 34 is pressed on the surface 203 of a workpiece, the surface of a workpiece is not damaged. Then, when the machine tool moves the counterbore arbor 11 forward or backward, the cutting tool can be made to appear and disappear automatically.

  Further, according to the present embodiment, the main shaft connects the main shaft main portion 12, the shaft tip member 22 and the pivot 23 as the blade support portion that supports the blade 13, and the main shaft main portion and the blade support portion. It has the screw | thread 21 as a connection part, and a connection part is comprised so that both may be disconnected, when an excessive pulling force is added between the main shaft main part and the blade support part. As a result, when the cutting tool 13 is automatically retracted, even if the cutting tool does not completely immerse to the storage position and protrudes from the window 28 to the outer diameter side, the counterbore arbor from the lower hole 202 can be obtained. When pulling out 11, the blade 13 collides with the back surface 204 of the workpiece 201, and an excessive pulling force that tries to separate the main shaft main portion 12 and the shaft tip member 22 is applied to the screw 21. Thereby, the main shaft main part 12 and the shaft tip member 22 are separated, and the cutting tool 13 is detached from the main shaft. Therefore, serious breakage of the spot facing arbor 11 and the workpiece 201 can be prevented.

  Further, according to the present embodiment, the groove 27 extending in the circumferential direction is formed on the outer peripheral surface of the main shaft main portion 12, and the protrusion engaging with the groove 27 is formed on the inner peripheral surface of the guide sleeve 16. The screw tip 26t is fixed, and the screw tip 26t is selectively held by the one end 27a and the other end 27b of the groove 27. Since the one end portion 27a corresponds to the first rotation position of the guide sleeve 16, and the other end portion 27b corresponds to the second rotation position of the guide sleeve 16, the cutting tool 13 can be easily moved in and out. 13 can be held in the storage position or the protruding position.

  Further, according to the present embodiment, the main shaft main portion 12 has the cutting fluid passage 36 that extends from the rear end portion in the axial direction toward the distal end side and ejects the cutting fluid to the cutting tool 13 at the protruding position. Thereby, it becomes possible to supply cutting fluid efficiently to a counterbore hole, and counterbore processing can be performed suitably.

  Next, a counterbore arbor according to a modification of the present invention will be described with reference to FIG. The counterbore arbor 41 shown in FIG. 12 is common to the counterbore arbor 11 described above except for the cutting tool. The cutting tool 43 of the counterbore arbor 41 has a cutting tool body 46 that is attached to a pivot and rotates, and insert chips 44 and 45 that are attached to the cutting tool body 46 and serve as cutting parts for cutting a workpiece. Specifically, the insert tool 44 is provided at the rear end edge of the cutting tool body 46 that faces the axial direction rearward of the counterbore arbor 41, and the blade portion 45 of the insert chip is provided at the front end edge of the cutting tool body 46 that faces the axial direction front. Have

  According to this modification, since the blade portions are respectively provided on the axial rear end side and the axial front end side, the rear end blade portion 44 is provided on the back surface 204 of the workpiece 201 into which the counterbore arbor 41 is inserted. The counterbore can be used to form a counterbore hole 205, and the surface 203 of the workpiece 201 can also be subjected to a face counterbore process using the front edge side blade portion 45. Holes 206 can be formed. Then, a counterbore hole 209 can be formed by subjecting the front surface 208 of the back-side workpiece 207 closer to the front side than the workpiece 201 to a front counterbore process. Furthermore, the counterbore arbor 41 can be inserted into the pilot hole 210 of the back-side workpiece 207, and the back-side counterbore processing can be performed on the back surface 211 of the back-side workpiece 207. become. In addition, by selecting a longer overall length of the counterbore arbor 41, it is possible to perform counterbore processing on a backside workpiece (not shown) located further on the front side than the backside workpiece 207.

  Next, a counterbore arbor according to another embodiment of the present invention will be described with reference to FIG. FIG. 13 is a side view of an essential part showing another embodiment of the present invention in partial cross section. In this embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and different configurations will be described below. In the spot facing arbor 51 of the embodiment shown in FIG. 13, instead of the surface treatment layer 16s, a pipe member 52 whose outer peripheral surface is subjected to a low friction treatment is provided.

  The pipe member 52 is disposed on the distal end side in the axial direction with respect to the annular step 34, and movement in the rear in the axial direction is restricted by the annular step 34. A snap ring 53 that extends in the circumferential direction along the outer peripheral surface of the guide sleeve 16 is provided in the vicinity of the window 28. The snap ring 53 is disposed behind the window 28 in the axial direction, and prevents the pipe member 52 from slipping forward in the axial direction. Preferably, the axial dimension of the pipe member 52 is longer than the length dimension of the lower hole 202. On the outer peripheral surface of the pipe member 52, a surface treatment layer 52s subjected to low friction treatment is formed. The surface treatment layer 52s includes, for example, ion nitriding, DLC (Diamond Like Carbon) coating, TiN (titanium nitride) coating, and mirror surface lapping.

  According to the counterbore arbor 51 of the embodiment shown in FIG. 13, the pipe member 52 is attached to the outer peripheral surface of the guide sleeve 16 and at least in a region in contact with the prepared hole to be processed. During boring, the rotational resistance can be reduced between the outer periphery of the spot facing arbor 51 and the inner peripheral surface of the prepared hole. The pipe member 52 may rotate together with the guide sleeve 16.

  As a modification, the pipe member 52 may be supported on the outer periphery of the guide sleeve 16 so as to be relatively rotatable on the rear end side in the axial direction with respect to the window 28.

  Next, a counterbore arbor according to still another embodiment of the present invention will be described with reference to FIG. FIG. 14 is an exploded perspective view schematically showing still another embodiment of the present invention. In this embodiment, the same components as those in the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and different configurations will be described below. In the counterbore arbor 61 shown in FIG. 14, a cylindrical main shaft 62 extending along the axis and having an axial rear end that can be attached to a holder of a machine tool, and a front end of the main shaft 62 are covered. Provided with a guide sleeve 16 and a cutting tool 13 attached to the end of the main shaft 62.

  A recess 19 for accommodating the blade 13 is formed behind the front end 62 s of the main shaft 62. A groove 63 extending in parallel with the axis of the counterbore arbor 61 is formed on the outer periphery of the main shaft 62. The groove 63 extends across the main shaft front end 62 s, the recess 19, and a region 62 k behind the recess 19.

  The cutting tool 13 is provided in the middle of the pivot 64 that extends linearly. Both ends of the pivot 64 protrude from the blade 13 respectively. A pivot 64 that pivotally supports the blade 13 is accommodated in the groove 63. As a result, the tip 64s of the pivot 64 is disposed at the main shaft tip 62s, and the rear end region of the pivot 64 is disposed at the main shaft rear end region 62k.

  The guide sleeve 16 rotates relative to the main shaft 62. Then, the cutting tool 13 is held at the storage position in the recess 19 by covering the cutting tool 13 at the first rotational position in the circumferential direction. Further, by exposing the blade 13 from the window 28 at the other second rotational position in the circumferential direction, the blade 13 is protruded radially outward from the window 28 to a protruding position.

  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 counterbore cutting tool according to the present invention is advantageously used in a machine tool.

  DESCRIPTION OF SYMBOLS 11 Counterbore arbor, 12 Main shaft main part, 13 Cutting tool, 14 Shank part, 16 Guide sleeve, 16s Surface treatment layer, 17 Flange part, 19 Recessed part, 21 Screw, 22 Shaft tip member, 23 Axis, 24 Spring, 26 Screw 26t Screw tip, 27 groove, 28 window, 29 spring, 32 flange, 34 annular step, 35 cushioning material, 36 cutting fluid passage, 41 counterbore arbor, 43 cutting tool, 44, 45 insert tip (blade), 46 Blade body, 51 Counterbore arbor, 52 Pipe member, 53 Snap ring, 61 Counterbore arbor, 62 Main shaft, 63 groove, 64 Axis, 101 Holder, 201 Workpiece, 202 Pilot hole

Claims (10)

A main shaft extending along the axis and having an axial rear end that can be attached to a holder of a machine tool;
A cutting tool that is pivotally supported at the tip end in the axial direction of the main shaft and falls into a storage position that falls along the main shaft, and a protruding position that stands up with respect to the main shaft,
An urging member for urging the cutting tool to urge the blade to the protruding position;
A cylindrical body provided on the outer periphery of the main shaft so as to be relatively rotatable, having a window on a side surface, and holding the blade tool in the storage position by covering the blade tool at a first rotation position in one circumferential direction, A counterbore cutting tool, comprising: a guide sleeve that projects the blade tool radially outward from the window to the projecting position by exposing the blade tool from the window at the other circumferential second rotation position.   2. The counterbore cutting according to claim 1, further comprising a low-friction portion provided on an outer peripheral surface of the guide sleeve and provided in at least a region in contact with a lower hole of the workpiece to be machined to reduce friction with the workpiece. tool.   The counterbore cutting tool according to claim 2, wherein the low friction portion is a surface treatment layer formed on an outer peripheral surface of the guide sleeve.   The counterbore cutting tool according to claim 2, wherein the low friction portion is a pipe member attached on an outer peripheral surface of the guide sleeve.   The seat according to any one of claims 1 to 4, wherein the guide sleeve includes a step contacting the surface of the workpiece during advancement, and the step is provided with a cushioning material that reduces a collision with the workpiece. Boring tool.   The main shaft has a main part, a blade support part that supports the blade, and a connecting part that connects the main part and the blade support part, and the connection part supports the main part and the blade tool. The counterbore cutting tool according to any one of claims 1 to 5, wherein an excessive pulling force is applied between the two parts and the connection between the two is released. A groove extending in the circumferential direction is formed on one of the inner peripheral surface of the guide sleeve or the outer peripheral surface of the main shaft,
On the other of the inner peripheral surface of the guide sleeve or the outer peripheral surface of the main shaft, a protrusion that engages with the groove is formed,
The counterbore cutting tool according to any one of claims 1 to 6, wherein the protrusion is selectively held at one end and the other end of the groove.   The counterbore cutting tool according to any one of claims 1 to 7, wherein the main shaft includes a cutting fluid passage that extends from an axial rear end portion toward a distal end side and ejects cutting fluid to the cutting tool at the protruding position. .   The counterbore cutting tool according to any one of claims 1 to 8, wherein the blade has a blade portion on an axial rear end side and an axial front end side. The counterbore cutting tool according to any one of claims 1 to 9, wherein the blade has a blade body and an insert tip that is attached to the blade body and cuts a workpiece.

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