JP7345291B2 - Cutting tools, tool holders and tool fixing structures - Google Patents

Description

The present disclosure relates to a tool holder included in a lathe that performs skiving processing, a cutting tool fixed to the tool holder, and a tool fixing structure for fixing the cutting tool to the tool holder.

In so-called "general lathe processing" performed by a general lathe, a workpiece is cut by moving a cutting tool in a direction parallel to the rotation axis of the workpiece. On the other hand, in recent years, technological development of "skiving" in which a workpiece is cut by moving a cutting tool in a direction perpendicular to the rotational axis of the workpiece has been progressing (for example, see Patent Document 1).

JP 2019-14037 (Paragraph [0010], Figure 1)

By the way, skiving machining can increase the surface roughness of the machined surface compared to general lathe machining, so it is possible to switch from a general lathe machined product to a skiving machined product. Progress has been made in recent years. In addition, there is an increasing demand for further improvement in the processing accuracy of skiving processing.

The invention according to claim 1, which has been made to solve the above problem, is a tool fixing structure for fixing a cutting tool to a tool holder of a lathe that performs skiving processing, the tool fixing structure being provided on at least the tool holder and the cutting tool. , a fastening mechanism that applies a first acting force to the cutting tool in a first direction perpendicular to the blade line of the cutting tool; and a fastening mechanism formed on the tool holder that approaches each other toward one of the first directions. and a V-shaped groove having a pair of V-shaped inner surfaces parallel to the blade line, and a pair of V-shaped grooves formed in the cutting tool and pressed against the pair of V-shaped inner surfaces by the first acting force. The fastening mechanism provided on the tool holder is a tool fixing structure formed on a bottom surface of the V-shaped groove sandwiched between the pair of V-shaped inner surfaces.

In the invention of claim 2, the fastening mechanism includes a bolt, a fastening part insertion hole that passes through the cutting tool in the first direction and into which the bolt is inserted, and is formed on the bottom surface of the V-shaped groove. 2. The tool fixing structure according to claim 1, further comprising: a screw hole into which the bolt is screwed.

According to a third aspect of the invention, the V-shaped groove opens toward a second direction perpendicular to both a rotation axis of a work rotationally driven by the lathe and a feeding direction of the tool holder with respect to the work, and The tool holder is formed with a chip guide surface that is inclined so as to gradually move away from the rotational axis of the work piece as it moves away from the V-shaped groove, on the destination side of the cutting tool in the feeding direction of the cutting tool. A tool fixing structure according to claim 1 or 2.

The invention according to claim 4 is the tool fixing device according to claim 3, wherein the chip guide surface is inclined so as to gradually move away from the rotation axis of the workpiece as it moves away from a chuck part of the lathe that chucks the workpiece. It is a structure.

The invention according to claim 5 is the tool fixing structure according to any one of claims 1 to 4, wherein the cutting tool has a symmetrical cross-sectional shape perpendicular to the cutting line.

The invention according to claim 6 is the tool fixing structure according to any one of claims 1 to 5, wherein the cutting tool has four blade portions so as to have a rotationally symmetrical shape of 90 degrees.

According to a seventh aspect of the invention, the cutting tool has a cutting edge side outer surface that is bent from the V-shaped outer surface to a side that is nearly parallel to the first direction and is flat to the cutting edge of the cutting tool. A tool fixing structure according to any one of claims 1 to 6, comprising: a tool fixing structure;

The invention according to claim 8 is a cutting tool that is fixed to a tool holder of a lathe that performs skiving processing, the cutting tool being inserted into the tool holder by penetrating the cutting tool in a first direction orthogonal to the blade line. A fastening part insertion hole into which a bolt or other fastening part for fastening is inserted, and a fastening part insertion hole that is arranged on both sides with the fastening part insertion hole in between, and which approach each other as they move away from the cutting edge of the cutting tool in the first direction. and a pair of V-shaped outer surfaces parallel to the blade line.

The invention according to claim 9 is the cutting tool according to claim 8, wherein a cross-sectional shape perpendicular to the blade line is bilaterally symmetrical.

The invention according to claim 10 is the cutting tool according to claim 8 or 9, which has four blade portions so as to have a rotationally symmetrical shape of 90 degrees.

The invention according to claim 11 is any one of claims 8 to 10, which has a cutting edge side outer surface that is bent from the V-shaped outer surface to a side that is nearly parallel to the first direction and is flat to the cutting edge. A cutting tool according to claim 1.

The twelfth aspect of the invention is a tool holder for holding a cutting tool for a lathe that performs skiving processing, wherein the bolt is threadedly engaged with a bolt that passes through the cutting tool in a first direction orthogonal to the blade line of the cutting tool. and a V-shaped groove having a pair of V-shaped inner surfaces that approach each other in one direction in the first direction and are parallel to the blade line , the pair of V-shaped inner surfaces being , tool holders arranged on both sides of the screw hole therebetween .

According to a thirteenth aspect of the invention, the V-shaped groove opens toward a second direction perpendicular to both a rotation axis of a work rotationally driven by the lathe and a feeding direction of the tool holder with respect to the work, and The tool holder is formed with a chip guide surface that is inclined so as to gradually move away from the rotational axis of the work piece as it moves away from the V-shaped groove, on the destination side of the cutting tool in the feeding direction of the cutting tool. A tool holder according to claim 12.

The invention of claim 14 is the tool according to claim 13, wherein the chip guide surface is inclined so as to gradually move away from the rotation axis of the workpiece as the side of the lathe moves away from a chuck part that chucks the workpiece. It is a holder.

In the tool fixing structure according to the first aspect, the first acting force directed in the first direction orthogonal to the blade line of the cutting tool is applied to the cutting tool by the fastening mechanism. Further, the tool holder is formed with a V-shaped groove having a pair of V-shaped inner surfaces that approach each other toward one side of the first direction and are parallel to the blade line. Then, the pair of V-shaped outer surfaces of the cutting tool are pressed against the pair of V-shaped inner surfaces by the first acting force. As a result, the cutting tool is fixed by being pushed from three different directions in the plane perpendicular to the imaginary cutter line, and the fixation is stable even when receiving loads from the workpiece in various directions. The processing accuracy of bing processing is improved. Note that the tool fixing structure of claim 1 described above can be obtained by providing the cutting tool and the tool holder with the configurations of claims 8 and 12 that have not existed before.

Further, the fastening mechanism may cause the first acting force to act on the cutting tool indirectly, or may act on the cutting tool directly. Specifically, as an example of indirectly applying the first acting force to the cutting tool, a wedge is pushed in a direction perpendicular to the first direction by a fastening mechanism, and the cutting tool is pushed in the first direction by the wedge. An example of the structure in which the first acting force is directly applied to the cutting tool is the structure according to claim 2.

The V-shaped groove may be opened forward in the feeding direction of the tool holder relative to the workpiece, or may be opened backward in the feeding direction. Moreover, as in the configurations of claims 3 and 13, the V-shaped groove may open toward a second direction perpendicular to both the rotation axis of the workpiece and the direction in which the tool holder feeds the workpiece. In this case, according to the configurations of claims 3 and 13, the chips resulting from the skiving process are guided by the chip guide surface, the scattering direction is stabilized, and the chips can be easily collected. Moreover, according to the configurations of claims 4 and 14, the chip guide surface guides the chips away from the chuck part of the lathe, making it easier to clean the chuck part.

In the structures of claims 5 and 9, two blade parts can be used by changing the angle of the cutting tool by 180 degrees and attaching it to the tool holder.

In the configurations of claims 6 and 10, four blade parts can be used by attaching the cutting tool to the tool holder while changing the angle by 90 degrees.

As in the configurations of claims 7 and 11, the cutting tool can be provided with a compact structure by being provided on the outer surface of the cutting tool that is bent from the V-shaped outer surface and formed flat to the cutting edge.

A perspective view of a lathe according to a first embodiment of the present disclosure Perspective view of tool holder Perspective view of cutting tool and tool holder Side sectional view of cutting tool and tool holder Conceptual diagram to explain the load that a cutting tool receives from a workpiece Side sectional view of the cutting tool and tool holder of the second embodiment Exploded perspective view of tool holder (A) Front view of cutting tool and tool holder, (B) Front view of tool holder, (C) Rear view of tool holder (A) A plan view of the cutting tool and tool holder of the third embodiment, (B) A side view of the cutting tool and tool holder, (A) Front view of the cutting tool and tool holder, (B) Front view of the tool holder, (C) Rear view of the cutting tool and tool holder A perspective view of the cutting tool and tool holder of the fourth embodiment Graph showing experimental results (A) Front view and (B) side view of a cutting tool according to a modified example

[First embodiment]
The present embodiment of a lathe 100 including a cutting tool 30A, a tool holder 10A, and a tool fixing structure for fixing them according to the present disclosure will be described below with reference to FIGS. 1 to 5. This lathe 100 performs skiving processing, and has a known structure except for the cutting tool 30A and tool holder 10A. That is, the lathe 100 includes a chuck part 102 on a main shaft 101 having a horizontal rotation axis, and the rod-shaped workpiece W is held in a centered state by the chuck part 102. Further, in front of the main shaft 101, a center tool (not shown) that abuts against the tip of the workpiece W and rotates together with the workpiece W is provided. Then, the work W is rotationally driven, for example, in a clockwise direction when viewed from the center tool side.

The cutting tool 30A, together with the tool holder 10A holding it, advances in a direction perpendicular to the rotational axis J1 of the workpiece W in a direction opposite to the circumferential speed direction of the workpiece W and approaches the workpiece W. It is pressed to a position offset from the axis J1. Here, the feeding direction of the tool holder 10A may be any of the vertical direction, the horizontal direction, and the oblique vertical direction, and if the contact position of the cutting tool 30A on the workpiece W is shifted from the rotation axis J1, the rotation axis The feeding direction may be above, below, on the side, or on the diagonal side of J1, but in the lathe 100 of this embodiment, the feeding direction is, for example, a horizontal direction perpendicular to the rotation axis J1, and the cutting tool 30A contacts the workpiece W. The position is below the rotation axis J1.

Hereinafter, in order to explain the tool holder 10A and the cutting tool 30A in detail, the horizontal direction parallel to the rotation axis J1 is referred to as the "X direction", and the horizontal direction orthogonal to the rotation axis J1 is referred to as the "Y direction". The vertical direction perpendicular to both directions is called the "Z direction." Further, the Z direction is also referred to as the vertical direction as appropriate. Furthermore, regarding the Y direction, when the tool holder 10A is separated from the workpiece W in the Y direction, the side closer to the workpiece W will be referred to as the "front side" and the opposite side will be referred to as the "rear side".

FIG. 2 shows the detailed shape of the tool holder 10A. The tool holder 10A has a structure in which a part of a rectangular parallelepiped whose planar shape is long in the Y direction is cut out. Counterbore holes 12 penetrating in the Z direction are formed at the four corners of the tool holder 10A. As shown in FIG. 4, it is fixed to the control output section 105 of the lathe 100 by a bolt B1 passed through the counterbore hole 12. The control output section 105 is controlled to be positioned at an arbitrary position in each of the XYZ directions.

As shown in FIG. 2, a V-shaped groove 13 is formed on the upper surface of the tool holder 10A, and extends in the horizontal direction and is inclined with respect to the Y direction and the X direction. The V-shaped groove 13 is inclined with respect to the X and Y directions so that one end of the side closer to the main shaft 101 is closer to the workpiece W, and one end of the V-shaped groove 13 is connected to one of the outer edges of the tool holder 10A. It is located in the middle of the long side of. Further, the other end of the V-shaped groove 13 is located at one corner of the tool holder 10A, and a counterbore hole 12 is opened within the other end of the V-shaped groove 13. Note that the counterbore hole 12 is formed to a depth such that the bolt B1 does not protrude into the V-shaped groove 13.

The V-shaped groove 13 is open to the horizontal upper surface 11A of the tool holder 10A. The upper surface 11A is formed in the entire rear side of the V-shaped groove 13 and in a constant width range along the V-shaped groove 13 in front of the V-shaped groove 13. A portion in front of the upper surface 11A is bent downward with respect to the upper surface 11A around a ridgeline 11R parallel to the V-shaped groove 13 to form a chip guide surface 11E. Moreover, a pair of counterbore holes 12 at the front end of the tool holder 10A are open to the chip guide surface 11E.

FIG. 4 shows a cross-sectional shape of the tool holder 10A taken along a cut plane perpendicular to the longitudinal direction of the V-shaped groove 13 and parallel to the Z direction. The V-shaped groove 13 is bent from the upper surface 11A, and has a pair of V-shaped inner surfaces 13A that are inclined toward each other as they go downward, and is vertically suspended from the lower end of the pair of V-shaped inner surfaces 13A. It has a pair of vertical surfaces 13B and a horizontal bottom surface 13C that communicates between the lower ends of the pair of vertical surfaces 13B. Further, screw holes 14 are bored at a plurality of positions in the longitudinal direction in the widthwise center of the bottom surface 13C, and extend vertically downward from the bottom surface 13C.

As shown in FIG. 3, the cutting tool 30A has an elongated shape with substantially the same length as the V-shaped groove 13. As shown in FIG. 4, the cutting tool 30A includes a pair of V-shaped outer surfaces 33 that are in surface contact with a pair of V-shaped inner surfaces 13A of the V-shaped groove 13, and a lower end of the pair of V-shaped outer surfaces 33. It has a lower surface 38 parallel to the bottom surface 13C of the V-shaped groove 13. Further, the rear V-shaped outer surface 33 (the right V-shaped outer surface 33 in FIG. 4) has a smaller vertical width than the front V-shaped outer surface 33 (the left V-shaped outer surface 33 in FIG. 4). There is. The upper end of the V-shaped outer surface 33 on the rear side is located below the upper end of the V-shaped inner surface 13A, and the upper end of the V-shaped outer surface 33 on the front side is located below the upper end of the V-shaped inner surface 13A. Almost overlap. The cutting tool 30A also includes a cutting edge side outer surface 34 vertically rising from the upper end of the V-shaped outer surface 33 on the front side, and an upper first outer surface 34 bent obliquely downward and rearward from the upper end of the cutting edge side outer surface 34. A blade portion 39 is provided in which a sloped surface 35 is formed, and a blade line 31 is a ridgeline where the outer surface 34 on the cutting edge side and the upper first sloped surface 35 intersect. On the upper surface of the cutting tool 30A, there is a stepped surface 36 that hangs vertically downward from the rear part of the upper first inclined surface 35, and a V-shaped surface that is parallel to the upper first inclined surface 35 and between the lower end of the stepped surface 36 and the rear side. An upper second inclined surface 37 communicating with the upper end of the outer surface 33 is provided. In this embodiment, the outer surface 34 on the cutting edge side serves as a rake face of the blade portion 39, and the upper first inclined surface 35 serves as a flank surface of the blade portion 39.

Further, as shown in FIG. 3, a plurality of counterbore holes 32 are formed in the cutting tool 30A at a plurality of positions in the longitudinal direction and penetrate in the vertical direction, and the bolt B2 passed through the counterbore holes 32 is shown in FIG. As shown, the cutting tool 30A is fixed to the tool holder 10A by being tightened into the screw hole 14 of the tool holder 10A.

Note that the stepped surface 36 is located on the front side of the counterbore hole 32. Further, the blade portion 39 of the cutting tool 30A is made of a member (for example, a sintered body of cBN (cubic boron nitride) particles) that is harder than the entire cutting tool 30A.

The explanation regarding the configuration of this embodiment is above. Next, the effects of this embodiment will be explained. In the tool fixing structure of this embodiment, the first acting force directed in the Z direction (corresponding to the "first direction" in the claims) perpendicular to the blade line 31 of the cutting tool 30A is applied to the cutting tool by tightening the bolt B2. Acts on tool 30A. Further, the tool holder 10A is formed with a V-shaped groove 13 having a pair of V-shaped inner surfaces 13A that approach each other in one direction in the Z direction and are parallel to the blade line 31. Then, the pair of V-shaped outer surfaces 33 of the cutting tool 30A are pressed against the pair of V-shaped inner surfaces 13A by the first acting force. As a result, the cutting tool 30A is pushed and fixed from three different directions within the imaginary plane perpendicular to the blade line 31 (see forces F11, F12, F13 in FIG. 4), and various Stable fixation even when subjected to directional loads. In other words, the cutting tool 30A can be stably fixed because the load can be received on three surfaces facing different directions. This improves the processing accuracy of skiving processing.

In detail, as shown in the change from FIG. 5(A) to FIG. 5(B), in skiving processing, the cutting tool 30A is sent toward the rotating workpiece W, In the embodiment, the first load F1 including a force component directed in the opposite direction to the "Y direction") is applied, and when the workpiece W is initially brought into contact with the workpiece W, as shown in FIG. The workpiece W receives a second load F2 including a force component pulled by the workpiece W in a second direction (in the present embodiment, the Z direction) perpendicular to both the rotational axis J1 of the workpiece W (Y direction) and the rotation axis J1 of the workpiece W. Then, when cutting starts, as shown in FIG. 5(C), a third load F3 including a force component pushing against the workpiece W in the second direction (namely, the Z direction) is applied due to the back force of cutting. Note that the second load F2 is a load that the cutting tool 30A does not receive in general lathe processing.

In the tool fixing structure of this embodiment, even if the cutting tool 30A receives loads from various directions including the first to third loads F1, F2, and F3 due to the skiving process, the cutting tool Since the tool holder 10A presses and fixes the tool 30A from three different directions in the plane perpendicular to the blade line, the tool holder 30A is stabilized and the processing accuracy of the skiving process is improved. Further, by making the cutting tool 30A and the tool holder 10A have the above-mentioned structure that has not existed before, it becomes possible to obtain the above-described tool fixing structure.

In addition, in the tool holder 10A of this embodiment, the chip guide surface 11E provided in front of the V-shaped groove 13 guides chips from the skiving process away from the chuck part 102 of the lathe 100. cleaning becomes easier.

Furthermore, since the cutting tool 30A is provided with a blade edge side outer surface 34 that is bent from the V-shaped outer surface 33 and is formed flat up to the blade line 31, the cutting tool 30A is provided with the V-shaped outer surface 34 without the blade edge side outer surface 34. The cutting tool 30A becomes more compact than when the cutting tool 33 is extended to the blade line 31.

Note that the cutting tool 30A of this embodiment has approximately the same length as the V-shaped groove 13, but it may be shorter than the V-shaped groove 13 and have two counterbored holes 32, or may be shorter than the V-shaped groove 13 and have one counterbored hole. A tool provided with a hole 32 may be used by being fixed to the tool holder 10A. Further, in the tool fixing structure of the present embodiment, an example is shown in which a fastening mechanism is provided that directly applies the fastening force of the bolt B2 to the cutting tool 30A. It may also be configured to act on the cutting tool 30A. Specifically, for example, as in the structure disclosed in FIG. 3 of JP-A No. 2016-203286, a wedge is pushed between the cutting tool and the wall surface of the tool holder by tightening the bolt, and the wedge is orthogonal to the tightening force of the bolt. The cutting tool may be pressed in a direction such that a pair of V-shaped outer surfaces of the cutting tool and a pair of V-shaped inner surfaces of the tool holder are pressed in the pressing direction.

[Second embodiment]
Hereinafter, a tool holder 40 and a cutting tool 30B according to a second embodiment of the present disclosure will be described with reference to FIGS. 6 to 8. The tool holder 40 of this embodiment includes a rotating base part 50 and a fixed base part 41. The rotating base portion 50 has a structure in which a shaft 51 having a circular cross section hangs down from a head portion 52 .

The head portion 52 has a substantially rectangular parallelepiped shape, and the lower surface of the head portion 52 is a flat surface perpendicular to the rotation axis, which is also the central axis of the shaft 51.

A V-shaped groove 13 having substantially the same cross-sectional shape as the V-shaped groove 13 of the first embodiment described above horizontally traverses the front surface of the head portion 52 . Further, as shown in FIG. 8(B), the upper V-shaped inner surface 13A of the V-shaped groove 13 has a smaller vertical width than the lower V-shaped inner surface 13A. As shown in FIG. 6, the front edge of the upper V-shaped inner surface 13A is located rearward than the front edge of the lower V-shaped inner surface 13A. Further, as shown in FIG. 8(B), a through hole 52A is formed at the center of the bottom surface 13C in the vertical and horizontal directions, and extends perpendicularly to the bottom surface 13C and horizontally penetrates the head portion 52. Further, as shown in FIG. 6, the rear surface 55 of the head portion 52 is a plane perpendicular to the through hole 52A.

The upper part of the head portion 52 is provided with a horizontal upper surface 54A on the front side, and is also provided with an inclined upper surface 54B that bends downward from the rear of the horizontal upper surface 54A and slopes to a rear surface 55. Furthermore, a pair of triangular chamfered surfaces 53 are provided at both corners of the sloping upper surface 54B and both side surfaces so that the chamfer width gradually decreases from the rear end toward a position closer to the front end. (See FIG. 8(C)).

As shown in FIG. 7, the fixed base portion 41 has a shape in which a truncated pyramid is superimposed on a rectangular parallelepiped having a square planar shape, and the inclined side surface of the truncated pyramid portion serves as a chip guide surface 41B. In addition, counterbore holes 41F vertically pass through the four corners of the fixed base portion 41, and as shown in FIG. The fixed base portion 41 is fixed to the control output portion 105 by being screwed into the control output portion 105 .

Further, a support hole 42 vertically passes through the center of the planar shape of the fixed base portion 41. As shown in FIG. 6, the support hole 42 includes a small diameter part 42B and a large diameter part 42A arranged vertically, and has a horizontal stepped surface 42C between them. Further, a fitting sleeve 49 and a presser cover 48 are fitted inside the support hole 42 . The fitting sleeve 49 has a large-diameter sleeve 49A that fits exactly into the large-diameter portion 42A, and a small-diameter sleeve 49B that fits exactly within the small-diameter portion 42B. The inner surface of the surface is continuous. Further, the holding lid 48 has substantially the same shape as the fitting sleeve 49, and is fitted below the large diameter sleeve 49A within the large diameter portion 42A. By attaching the fixed base portion 41 to the control output portion 105, the upper surface of the large diameter sleeve 49A is pressed against the stepped surface 42C of the support hole 42 via the presser lid 48.

As shown in FIG. 7, the fitting sleeve 49 is provided with a storage chamber (not shown) for storing a fluid inside the small-diameter sleeve 49B side. Further, the large-diameter sleeve 49A is provided with a screw hole (not shown) communicating with the accommodation chamber, and a screw operation part B4 screwed into the screw hole. Further, the fixed base portion 41 is formed with a through hole 41E for operating the screw operation portion B4 from the outside. Then, by the screwing operation of tightening the screwing operation portion B4, the internal pressure of the fluid increases, and the small diameter sleeve 49B bulges in and out.

As shown in FIG. 6, the rotating base part 50 is constructed such that the shaft 51 is fitted inside the fitting sleeve 49, and the lower surface of the head part 52 is overlapped with the upper surface 41A of the fixed base part 41. It is assembled into. When the screw operation part B4 is loosened, the rotary base part 50 can be rotated to any rotational position relative to the fixed base part 41, and the rotary base part 50 can be extracted from the fixed base part 41. . Moreover, when the screw operation part B4 is tightened, the rotating base part 50 is fixed to the fixed base part 41 so as to be non-rotatable and non-movable up and down. Note that, as shown in FIG. 7, a scale 41M indicating the turning angle of the head portion 52 with respect to the fixed base portion 41 is engraved on the upper surface 41A of the fixed base portion 41.

An example of a cutting tool 30B fixed to the tool holder 40 is shown in FIGS. 6 and 8(A). This cutting tool 30B has a substantially truncated pyramid shape that is rotationally symmetrical at 90 degrees. Here, a 90 degree rotationally symmetrical shape refers to a shape that looks the same even if rotated 90 degrees. Specifically, the cutting tool 30B has a square front shape, and as shown in FIG. 6, it has a substantially truncated pyramid shape that narrows toward the rear. Note that the rear surface 38B of the cutting tool 30B is parallel to the front surface 35B.

The cutting tool 30B has a counterbore hole 32 passing through the center of the square that is the front shape. Even if the cutting tool 30B is rotated 90 degrees around the center axis of the counterbore hole 32, the same shape appears. In addition, each of the four-directed slopes of the cutting tool 30B has a V-shaped outer surface 33B that can come into surface contact with the V-shaped inner surface 13A of the V-shaped groove 13, and a front edge of the V-shaped outer surface 33B and a front surface 35B. and a cutting edge side outer surface 34B that communicates between the two. Four blade portions 39 are provided, each having a blade line 31 defined by a ridgeline where the front surface 35B intersects with each outer surface 34B on the edge side.

In this embodiment, the outer surface 34B on the edge side serves as a flank of the blade portion 39, while the front surface 35B serves as a rake surface of the blade portion 39.

The bolt B3 passed through the counterbore hole 32 of the cutting tool 30B is also passed through the through hole 52A in the head portion 52 of the tool holder 40, and is used as a part of the tool holder 40 directed to the rear surface 55 of the head portion 52. It is screwed into a screw hole N1 of a nut N. As a result, a pair of opposing V-shaped outer surfaces 33B of the four V-shaped outer surfaces 33B of the cutting tool 30B are pressed against a pair of V-shaped inner surfaces 13A of the V-shaped groove 13, which is the same as in the first embodiment. Similar to the tool holder 10A, the cutting tool 30B is fixed to the tool holder 40 by being pushed from three different directions in a plane perpendicular to the blade line 31. Then, the blade portion 39 located at the upper part of the cutting tool 30B is in a state of protruding upward from the head portion 52 and is used for skiving processing. That is, the front surface 35B of the cutting tool 30B is directed toward the workpiece W, the blade line 31 of the upper blade portion 39 of the cutting tool 30B is inclined with respect to the Y direction, and the tool holder 40 moves forward in the Y direction. , the blade portion 39 of the cutting tool 30B is pressed against the work W to perform skiving.

Here, as described above, the cutting tool 30B of this embodiment is also fixed to the tool holder 40 by being pushed from three different directions in the plane perpendicular to the blade line, so that it can be separated from the workpiece W rotating by skiving. The fixation is stable even when subjected to loads in various directions, improving the processing accuracy of skiving processing.

In the tool holder 40 of this embodiment, the cutting tool 30B can be rotated around the shaft 51 to adjust the machining conditions, and in this respect as well, the machining accuracy of skiving machining can be improved. Further, by rotating the screw operation portion B4 of the fitting sleeve 49, the rotating base portion 50 can be easily fixed to and released from the fixed base portion 41. Furthermore, since the rotary base portion 50 can be removed from the fixed base portion 41, the cutting tool 30B is fixed to a plurality of rotary base portions 50 in advance, and the rotary base 50 attached to the fixed base portion 41 is replaced. This allows the cutting tool 30B to be replaced quickly. At that time, rotating base parts 50B and 50C of third and fourth embodiments, which will be described later, may be attached to the fixed base part 41 instead of the rotating base part 50 of this embodiment. Moreover, since the cutting tool 30B of this embodiment has a shape that is symmetrical to rotation by 90 degrees, the four blade parts 39 of the tool holder 40 can be used by changing the angle by 90 degrees and attaching it to the tool holder 40. can do.

[Third embodiment]
Hereinafter, a rotating base portion 50B and a cutting tool 30C according to a third embodiment of the present disclosure will be described with reference to FIGS. 9 and 10. The rotating base portion 50B of this embodiment has the same shaft 51 as the rotating base portion 50 of the second embodiment, but has a different head portion 52B. Then, as shown in FIG. 9(B), it is assembled to the fixed base portion 41 described in the second embodiment and used as a tool holder 40B.

Specifically, as shown in FIG. 10(B), the front surface of the head portion 52B of the rotating base portion 50B has a horizontally long rectangular shape when viewed from the front, and is provided with a horizontally long V-shaped groove 13. As shown in FIG. 9(B), the V-shaped groove 13 is formed such that an imaginary center surface 50Z located at the center with respect to the pair of V-shaped inner surfaces 13A is inclined downward toward the front. It is sloping. Further, the rear surface 55 of the head portion 52B is parallel to the bottom surface 13C of the V-shaped groove 13 and is inclined with respect to the pivot axis of the shaft 51. Furthermore, a pair of through holes 52A shown in FIG. 10(B) are formed in the head portion 52B so as to be orthogonal to the bottom surface 13C and the rear surface 55, as shown in FIG. 9(B).

Further, as shown in FIGS. 9(A), 10(A), and 10(C), the cutting tool 30C has an elongated shape slightly longer than the V-shaped groove 13, and the cutting tool 30C has an elongated shape that is slightly longer than the V-shaped groove 13. It has a pair of V-shaped outer surfaces 33 that abut against the V-shaped inner surface 13A of the head part 52B, and a pair of through holes 32B that oppose the pair of through holes 52A of the head portion 52B. The bolt B3 passed through the washer BW is passed through the pair of through holes 32B and the pair of through holes 52A, and is screwed into the nut N on the rear surface 55 side. Further, the cutting tool 30C is provided with a blade portion 39 only at one corner disposed on the upper side, and a portion between the blade line 31 of the blade portion 39 and the upper V-shaped outer surface 33 is the V-shaped outer surface 33. The outer surface 34 on the cutting edge side lies on the side closer to being parallel to the central axis of the bolt B3.

As shown in FIG. 9(B), a rotary contact portion 59 projects from the lower part of the head portion 52B to the rear side of the rear surface 55. As shown in FIG. 9A, the rotary contact portion 59 has an arcuate planar shape, and the lower surface of the rotary contact portion 59 is flush with the lower surface of the head portion 52B, and the upper surface of the fixed base portion 41. It comes into contact with 41A.

According to the rotating base portion 50B of this embodiment, the rotating contact portion 59 protrudes laterally from the shaft 51 and comes into contact with the upper surface 41A of the fixed base portion 41, so that the rotating base portion 50B resists the load from the workpiece W. becomes difficult to bend, and the cutting tool 30C is stably fixed. This stabilizes the shape of the skiving process performed by the cutting tool 30C.

[Fourth embodiment]
Hereinafter, a rotating base portion 50C according to a fourth embodiment of the present disclosure will be described with reference to FIG. 11. The rotating base portion 50C of this embodiment differs from the third embodiment only in the structure of the head portion 52C. Then, it is assembled to the fixed base portion 41 described in the second embodiment and used as a tool holder 40C. Specifically, the rotation base portion 50C includes a rotation abutment portion 70 that projects laterally from the shaft portion 51, and a support block 71 that projects upward from the rotation abutment portion 70. A V-shaped groove 13 is provided on the surface of the support block 71 facing toward the center of rotation of the shaft 51, and the aforementioned cutting tool 30C is fixed therein.

Similarly to the third embodiment, the rotary base portion 50C of this embodiment is less susceptible to bending deformation under load, and the shape of the skiving process by the cutting tool 30C is stabilized.

[Example]
The tool holder 40B and the cutting tool 30C described in the third embodiment are used to skive the workpiece W to have a constant outer diameter, and the method disclosed in FIG. 3 of JP-A No. 2016-203286 is As shown in the figure, a cutting tool with a flat plate-like blade on the upper end is held between a tool holder and prevented from coming off in the Z direction by frictional engagement. Skiving was performed under the same conditions as the actual product. A comparative product was manufactured, and the uniformity of the outer diameter in the longitudinal direction of the workpiece W was measured and graphed as shown in FIG.

According to the same graph, it can be confirmed that the comparative product has poor uniformity of the outer diameter immediately after the start of processing. This is because the cutting tool receives the aforementioned second load F2 (see Fig. 5(B)) from the work W immediately before starting machining, and lifts off the contact surface with the tool holder in the Z direction, and after starting machining, the cutting tool It is presumed that this is because the tool holder returns to the contact position with the tool holder. On the other hand, it can be confirmed that the uniformity of the outer diameter of the implemented product immediately after the start of machining is significantly improved compared to the comparative product.

[Other embodiments]
(1) Although the V-shaped groove 13 in the second to fourth embodiments opens forward in the feeding direction of the tool holder 40 with respect to the workpiece W, it may open backward in the feeding direction.

(2) The cutting tool 30B of the second embodiment had a rotationally symmetric shape of 90 degrees around the bolt B3, but the cutting tool 30B cuts a plurality of through holes 32D like the cutting tool 30D shown in FIG. In preparation for the central axis of the tool 30D, the shape may be rotationally symmetrical at 90 degrees around a portion other than the bolt.

(3) Although the pair of V-shaped inner surfaces 13A and the pair of V-shaped outer surfaces 33 in the embodiment described above were inclined symmetrically with respect to the central axes of the bolts B2 and B3, they were not symmetrical. Alternatively, the V-shaped inner surface 13A and the V-shaped outer surface 33 may be parallel to the central axes of the bolts B2 and B3.

(4) In the tool holder 40 of the second embodiment, the rotary base 50 and the fixed base portion 41 were constructed as separate parts, but the rotary base 50 and the fixed base 41 are constructed integrally. It's okay. The same applies to the tool holders 40B and 40C of the third and fourth embodiments.

10A, 40 Tool holder 11E, 41B Chip guide surface 13 V-shaped groove 13A V-shaped inner surface 14 Screw hole 30A, 30B, 30C, 30D Cutting tool 31 Blade line 33, 33B V-shaped outer surface 34, 34B Cutting edge side outer surface 40, 40B, 40C Tool holder 41 Fixed base part 42 Support hole 49 Fitting sleeve 50, 50B, 50C Rotating base part 51 Shaft 52, 52B, 52C Head part 100 Lathe 101 Main shaft 102 Chuck part B1 to B3, B5 Bolt B4 Thread Coupling operation part N1 screw hole

Claims (14)

A tool fixing structure for fixing a cutting tool to a tool holder of a lathe that performs skiving processing,
a fastening mechanism that is provided on at least the tool holder and the cutting tool and applies a first acting force to the cutting tool in a first direction perpendicular to the blade line of the cutting tool;
a V-shaped groove formed in the tool holder and having a pair of V-shaped inner surfaces that approach each other toward one side of the first direction and are parallel to the blade line;
a pair of V-shaped outer surfaces formed on the cutting tool and pressed against the pair of V-shaped inner surfaces by the first acting force ;
The fastening mechanism provided in the tool holder is a tool fixing structure formed on a bottom surface of the V-shaped groove sandwiched between the pair of V-shaped inner surfaces. The fastening mechanism includes:
bolt and
a fastening component insertion hole that penetrates the cutting tool in the first direction and into which the bolt is inserted;
The tool fixing structure according to claim 1, further comprising a screw hole formed in the bottom surface of the V-shaped groove and screwed into the bolt. The V-shaped groove opens toward a second direction perpendicular to both a rotation axis of a workpiece rotationally driven by the lathe and a feeding direction of the tool holder with respect to the workpiece,
The tool holder is formed with a chip guide surface that is inclined so as to gradually move away from the rotation axis of the workpiece as it moves away from the V-shaped groove, on the destination side of the cutting tool in the feeding direction of the cutting tool. The tool fixing structure according to claim 1 or 2. 4. The tool fixing structure according to claim 3, wherein the chip guide surface is inclined so as to gradually move away from the rotation axis of the workpiece as it moves away from a chuck part of the lathe that chucks the workpiece. 5. The tool fixing structure according to claim 1, wherein the cutting tool has a symmetrical cross-sectional shape perpendicular to the blade line. The tool fixing structure according to any one of claims 1 to 5, wherein the cutting tool has four blade portions so as to have a rotationally symmetrical shape of 90 degrees. 7. The cutting tool has a cutting edge side outer surface that is bent from the V-shaped outer surface to a side that is nearly parallel to the first direction and is flat to the cutting edge of the cutting tool. A tool fixing structure according to any one of claims. A cutting tool fixed to a tool holder of a lathe that performs skiving processing,
a fastening part insertion hole that penetrates the cutting tool in a first direction perpendicular to the blade line and into which a bolt or other fastening part for fastening the cutting tool to the tool holder is inserted;
a pair of V-shaped outer surfaces that are arranged on both sides of the fastening part insertion hole, that approach each other as they move away from the cutting edge of the cutting tool in the first direction, and that are parallel to the blade line; tool. The cutting tool according to claim 8, wherein a cross-sectional shape perpendicular to the blade line is symmetrical. The cutting tool according to claim 8 or 9, having four blade portions so as to have a rotationally symmetrical shape of 90 degrees. According to any one of claims 8 to 10, the cutting edge side outer surface is bent from the V-shaped outer surface to a side that is nearly parallel to the first direction and is flat to the cutting edge. cutting tools. A tool holder for holding a cutting tool of a lathe that performs skiving processing,
a bolt passing through the cutting tool in a first direction perpendicular to the cutting tool;
a screw hole into which the bolt is screwed;
a V-shaped groove having a pair of V-shaped inner surfaces that approach each other toward one of the first directions and are parallel to the blade line ;
The pair of V-shaped inner surfaces are arranged on both sides of the screw hole in between . The V-shaped groove opens toward a second direction perpendicular to both a rotation axis of a workpiece rotationally driven by the lathe and a feeding direction of the tool holder with respect to the workpiece,
The tool holder is formed with a chip guide surface that is inclined so as to gradually move away from the rotation axis of the workpiece as it moves away from the V-shaped groove, on the destination side of the cutting tool in the feeding direction of the cutting tool. The tool holder according to claim 12. 14. The tool holder according to claim 13, wherein the chip guide surface is inclined so as to gradually move away from the rotation axis of the workpiece as the side of the lathe moves away from a chuck portion that chucks the workpiece.

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